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`US008339798B2
`
`US 8,339,798 B2
`
`c12) United States Patent
`(IO) Patent No.:
`(45) Date of Patent:
`Dec. 25, 2012
`
`
`Minoo et al.
`
`(54)P RINTED CIRCUIT BOARDS WITH
`
`EMBEDDED COMPONENTS
`
`(75)Inventors: J ahan Minoo, San Jose, CA (US);
`
`
`
`
`
`Anthony P. N. Bidmead, Los Gatos, CA
`
`(US); Michael Nikkhoo, San Jose, CA
`(US)
`
`
`
`
`
`(73)Assignee: Apple Inc., Cupertino, CA (US)
`
`
`
`Kaminski 200/5 A
`3,973,091 A * 8/1976
`
`Keough et al. 200/5 A
`4,074,088 A * 2/1978
`Lowthorp 200/5 A
`
`4,127,752 A * 11/1978
`Burr et al.
`
`4,175,816 A 11/1979
`Furusawa et al. ............. 200/516
`
`
`
`4,207,448 A * 6/1980
`Corwin .
`200/5 A
`
`4,263,485 A * 4/1981
`Finlay
`
`5,826,708 A 10/1998
`
`
`Okamoto et al. ............. 200/516
`
`5,986,228 A * 11/1999
`
`Ando eta!. ................... 200/512
`6,388,218 Bl* 5/2002
`
`Watanabe et al.
`
`6,518,527 B2 2/2003
`
`
`
`6,730,869 B2 * 5/2004
`Zollo et al.
`
`6,928,726 B2 8/2005
`( *) Notice: Subject to any disclaimer, the term ofthis
`
`
`
`Ide et al. ....................... 200/516
`
`6,982,394 B2 * 1/2006
`
`
`
`patent is extended or adjusted under 35
`
`Kobayashi et al.
`7,094,985 B2 8/2006
`
`
`U.S.C. 154(b) by 194 days.
`
`Teruyama et al. ............ 200/516
`
`(Continued)
`
`FOREIGN PATENT DOCUMENTS
`
`DE
`
`3002772 C2 3/1984
`
`(Continued)
`
`Primary Examiner - Michail V Datskovskiy
`
`
`
`
`(74)Attorney,Agent, or Firm -TreyzLawGroup;G.Victor
`
`Treyz; Nancy Y. Ru
`
`(57)
`
`ABSTRACT
`
`(21)Appl. No.: 12/832,885
`
`(22)Filed:
`
`
`Jul. 8, 2010
`
`(65)
`
`
`
`P rior Publication Data
`
`
`
`US 2012/0008294 Al Jan. 12,2012
`
`(56)
`
`
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`(51)
`Int. Cl.
`H0SK 1118 (2006.01)
`H0SK 1103 (2006.01)
`Printed circuit boards are provided with embedded compo­
`
`
`
`H0SK 1/00 (2006.01)
`
`
`
`nents. The embedded components may be mounted within
`H0SK 1116 (2006.01)
`
`
`
`
`recesses in the surface of a printed circuit board substrate. The
`
`
`
`U.S. Cl. ........ 361/764; 361/761; 361/777; 361/781;
`(52)
`
`
`
`printed circuit board substrate may have grooves and buried
`200/5 A; 200/5 B; 200/516
`
`
`
`
`channels in which wires may be mounted. Recesses may be
`
`Field of Classification Search ............. 361/679.02,
`(58)
`
`
`
`provided with solder pads to which the wires may be soldered
`
`
`361/679.3, 679.15, 760-767, 784-788, 794-797;
`
`
`
`or attached with conductive adhesive. An integrated switch
`
`
`174/254-267; 20015A, 6 A, 512-517, 306,
`
`
`
`may be provided in an opening within a printed circuit board
`
`
`200/302.2, 292,406, 341-345, 521; 345/156-184;
`
`
`
`substrate. The integrated switch may have a dome switch
`
`
`455/550.1, 575.1, 556, 556.2; 29/622
`
`
`
`member that is mounted within the opening. A cover member
`
`
`
`See application file for complete search history.
`
`
`
`
`for the switch may be formed from a flexible layer that covers
`
`
`
`the dome switch member. Terminals for the integrated switch
`
`
`may be formed from conductive structures in an interior
`
`
`
`
`printed circuit board layer. Interconnects may be used to
`
`
`
`
`electrically connect embedded components such as switches,
`200/5 A
`3,600,528 A * 8/1971 Leposavic .
`
`
`
`
`
`
`
`integrated circuits, solder pads for wires, and other devices.
`200/5 R
`
`
`
`3,684,842 A * 8/1972 Boulanger
`
`
`
`
`
`3,725,907 A * 4/1973 Boulanger ...................... 341/22
`
`
`
`
`
`3,806,673 A * 4/1974 Boulanger
`200/5 A
`
`19 Claims, 21 Drawing Sheets
`
`14
`
`12
`
`34
`
`
`46
`34 34
`
`34
`
`34
`
`Ex.1012
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`

`US 8,339,798 B2
`
`Page 2
`
`
`
`U.S. PATENT DOCUMENTS
`
`FOREIGN PATENT DOCUMENTS
`
`7,676,242 B2 3/2010 Siddiqui et al.
`
`
`JP
`
`
`
`
`2003/0229795 Al* 12/2003 Kunigkeit et al. ............ 713/189 JP
`
`2007/0111380 Al 5/2007 Cho et al.
`
`
`2010/0265184 Al 10/2010 Jung
`
`*cited by examiner
`
`2006040808 A * 2/2006
`
`
`2009193467 A 8/2009
`
`
`Ex.1012
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`U.S. Patent Dec. 25, 2012
`Sheet 1 of 21
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`US 8,339,798 B2
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`
`Ex.1012
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`U.S. Patent Dec. 25, 2012 Sheet 2 of 21 US 8,339,798 B2
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`Ex.1012
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`
`U.S. Patent Dec. 25, 2012 Sheet 3 of 21 US 8,339,798 B2
`
`12A
`
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`
`12C
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`
`FIG. 3
`
`Ex.1012
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`
`U.S. Patent Dec. 25, 2012 Sheet 4 of 21 US 8,339,798 B2
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`Ex.1012
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`
`
`U.S. Patent Dec. 25, 2012 Sheet 5 of 21 US 8,339,798 B2
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`PORT
`
`12
`
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`
`FIG. 5
`
`FIG. 6
`
`Ex.1012
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`U.S. Patent Dec. 25, 2012 Sheet 6 of 21 US 8,339,798
`B2
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`Ex.1012
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`U.S. Patent
`Dec. 25, 2012
`
`Sheet 7 of 21 US 8,339,798 B2
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`Dec. 25, 2012
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`Ex.1012
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`U.S. Patent Dec. 25, 2012
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`Sheet 10 of 21 US 8,339,798 B2
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`U.S. Patent Dec. 25, 2012
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`US 8,339,798 B2
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`Ex.1012
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`U.S. Patent Dec. 25, 2012
`
`
`US 8,339,798 B2
`Sheet 12 of 21
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`40G
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`Ex.1012
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`U.S. Patent
`Dec. 25, 2012 Sheet 13 of 21
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`U.S. Patent Dec. 25, 2012 Sheet 14 of 21 US 8,339,798 B2
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`Ex.1012
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`U.S. Patent
`Dec. 25, 2012
`Sheet 15 of 21
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`US 8,339,798 B2
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`Ex.1012
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`U.S. Patent Dec. 25, 2012
`Sheet 16 of 21
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`Ex.1012
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`U.S. Patent Dec. 25, 2012
`Sheet 17 of 21
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`US 8,339,798 B2
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`U.S. Patent
`Dec. 25, 2012
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`Sheet 18 of 21 US 8,339,798 B2
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`U.S. Patent Dec. 25, 2012
`Sheet 19 of 21
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`US 8,339,798 B2
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`122
`
`ADDITIONAL
`COMPONENTS
`
`
`
`UNLAMINATED LAYERS
`
`MACHINING TOOLS
`
`
`
`UNLAMINATED LAYERS
`
`
`
`LAMINATING TOOLS
`
`
`
`LAMINATED LAYERS
`
`POSTPROCESSING TOOLS
`
`...---------'-----------, 130
`
`FINISHED PRINTED
`
`CIRCUIT BOARD
`
`ASSEMBLY TOOLS
`
`COMPLETED DEVICE
`
`FIG. 20
`
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`U.S. Patent Dec. 25, 2012 Sheet 20 of 21
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`US 8,339,798 B2
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`U.S. Patent Dec. 25, 2012 Sheet 21 of 21
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`US 8,339,798 B2
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`BRIEF DESCRIPTION OF THE DRAWINGS
`
`BACKGROUND
`
`SUMMARY
`
`1
`
`US 8,339,798 B2
`
`
`2
`
`PRINTED CIRCUIT BOARDS WITH
`
`EMBEDDED COMPONENTS
`
`for the integrated switch may be formed from conductive
`
`
`
`
`
`
`structures in an interior printed circuit board layer. Intercon­
`
`
`
`
`
`nects that include patterned printed circuit board conductor
`
`
`
`layers and vias formed by machining and laser drilling may be
`
`
`
`
`5 used to electrically connect embedded components such as
`This relates to assemblies of electrical and mechanical
`
`
`
`
`
`
`
`tact switches, integrated domes switches, microphones, inte­
`
`
`components for electronic devices, and, more particularly, to
`
`
`
`
`grated circuits, solder pads for wires, and other devices.
`
`
`
`ways in which to incorporate components into printed circuit
`
`
`
`
`Further features of the invention, its nature and various
`board structures.
`
`
`
`advantages will be more apparent from the accompanying
`Electronic devices use integrated circuits and electrical
`
`
`
`
`10 drawings
`
`
`
`and the following detailed description of the pre­
`
`
`
`components such as switches. These components are typi­
`ferred embodiments.
`
`
`
`cally mounted to the surface of a printed circuit board using
`solder.
`
`Printed circuit boards may be formed from substrates such
`
`
`
`
`
`
`
`
`
`as fiberglass-filled epoxy. In complex designs, multiple board 15
`FIG. 1 is a cross-sectional side view of an illustrative
`
`
`
`
`
`layers may be laminated to form a multilayer printed circuit
`
`
`
`
`printed circuit board containing an embedded switch in
`board.
`
`
`
`accordance with the embodiment of the present invention.
`
`
`
`In a typical printed circuit board arrangement, parts are
`
`FIG. 2 is a cross-sectional side view of an illustrative
`
`
`
`
`attached to the surface of the outermost board layer. Vias may
`
`
`
`
`
`printed circuit board showing how the printed circuit board
`
`
`be formed to interconnect board layers. Some boards have 20
`
`
`may be provided with vias of different types to interconnect
`
`included embedded microphones.
`
`
`
`components and printed circuit board layers in accordance
`
`
`Switches and other components such as the wires are gen­
`
`
`with an embodiment of the present invention.
`
`
`
`
`
`
`erally attached only to the surface of printed circuit boards.
`
`
`
`FIG. 3 is an exploded perspective view of an illustrative
`
`
`
`
`While this approach is sometimes acceptable, problems can
`
`
`
`
`
`printed circuit board showing how layers of the printed circuit
`
`
`
`
`arise when it is desired to form robust and compact structures.
`25
`
`
`
`board may be provided with holes, slots, and other openings
`
`
`
`
`
`Traditional component mounting approaches may result in
`
`
`
`
`to accommodate embedded components in accordance with
`
`
`
`
`
`boards that are not sufficiently strong or that have awkwardly
`
`
`an embodiment of the present invention.
`
`
`
`
`protruding components. Traditional approaches may also
`
`FIG. 4 is a cross-sectional side view of an illustrative
`
`
`
`
`raise concerns with environmental sealing, the strength with
`
`
`
`printed circuit board in which a packaged switch and an
`
`
`
`which structures are attached to a board, and manufacturabil-
`30
`
`
`
`
`integrated circuit have been embedded in accordance with an
`ity.
`
`
`embodiment of the present invention.
`
`
`It would therefore be desirable to be able to provide
`
`
`
`FIG. 5 is a cross-sectional side view of a printed circuit
`
`
`
`
`improved printed circuit board structures such as printed cir­
`
`
`board with embedded components such as a top-vented
`
`
`
`cuit board structures with embedded switches and other elec-
`
`
`
`
`
`microphone, a switch, and an integrated circuit in accordance
`
`
`
`
`trical components and improved methods for manufacturing
`35
`
`
`with an embodiment of the present invention.
`such boards.
`
`
`
`
`FIG. 6 is a cross-sectional side view of a printed circuit
`
`
`board with embedded components such as a bottom-vented
`
`
`
`
`
`microphone, a switch, and an integrated circuit in accordance
`
`
`40 with an embodiment of the present invention.
`Compact and robust electrical device accessories and other
`
`
`
`
`
`
`
`
`
`
`
`
`
`equipment may be formed using printed circuit boards with FIG. 7 is a cross-sectional side view of a printed circuit
`
`
`
`
`
`
`
`embedded components. Printed circuit board substrates may board showing how wires may be connected to the printed
`
`
`
`
`be formed from one or more layers of dielectric material. In
`
`
`
`
`circuit board using different arrangements in accordance with
`
`
`
`
`multilayer substrates multiple printed circuit board layers
`
`
`
`an embodiment of the present invention.
`
`
`
`
`may be laminated together. Conductive layers may be pat-45
`
`FIG. 8 is a cross-sectional side view of an illustrative
`
`
`terned to form interconnects. Interconnects may also be
`
`
`
`printed circuit board showing how a wire that runs along the
`
`
`
`
`formed by drilling vias. Vias may be drilled mechanically or
`
`
`
`
`
`surface of the printed circuit board may be attached to the
`using laser drilling.
`
`
`
`
`printed circuit board using a recessed solder pad in accor­
`
`
`
`
`
`Embedded components may be mounted within recesses in
`
`
`dance with an embodiment of the present invention.
`
`
`
`the surface of a printed circuit board substrate and other 50
`
`FIG. 9 is a cross-sectional side view of an illustrative
`
`
`
`
`openings. The openings may be well-shaped recesses such as
`
`
`
`
`printed circuit board showing how a wire that is partly
`
`
`
`
`
`square recesses that penetrate partway into the printed circuit
`
`
`
`
`
`recessed in the board using a groove in the upper surface of
`
`
`
`board substrate or may have the shapes of grooves or buried
`
`
`
`the board may be attached to the printed circuit board using a
`
`
`
`channels. Switches such as tact switches may be mounted
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`recessed solder pad in accordance with an embodiment of the
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`within printed circuit board substrate openings. Vias may be 55
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`present invention.
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`used to form connections to the terminals of embedded
`FIG. 10 is top view of an illustrative printed circuit board
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`switches.
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`showing how a wire that runs along the surface of the printed
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`Grooves and buried channels in a printed
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`circuit circuit board board or that is partly recessed in a groove in the
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`substrate may be used to mount wires. Surface
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`surface of the printed recesses and circuit board may be attached to the
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`other openings may be provided with solder pads to which the 60 printed circuit board using a recessed solder pad in accor­
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`wires may be soldered or attached with conductive adhesive. dance with an embodiment of the present invention.
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`Adhesive may be used to seal solder pad structures. FIG. 11 is a cross-sectional side view of an illustrative
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`An integrated switch may be formed in a recess within a printed circuit board showing how a wire that is routed
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`printed circuit board substrate. The integrated switch may through an interior cavity in the printed circuit board may be
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`have a dome switch member that is mounted within the 65 attached to the printed circuit board using a recessed solder
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`recess. A cover member for the switch may be formed from a pad in accordance with an embodiment of the present inven-
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`flexible layer that covers the dome switch member. Terminals tion.
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`Ex.1012
`APPLE INC. / Page 24 of 30
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`US 8,339,798 B2
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`FIG.12 is a top view ofa printed circuit board that has fully
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`Printed circuit boards in which components have been
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`embedded may be used in electronic devices such as desktop
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`embedded wires of the type shown in FIG. 11 in accordance
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`computers, portable computers, cellular telephones, media
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`with an embodiment of the present invention.
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`players, televisions, displays, headsets, adapters, cables,
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`FIG. 13 is a cross-sectional side view of an illustrative
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`5 speakers, radios, and other suitable equipment and accesso­
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`printed circuit board showing how a wire may be connected to
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`ries. When used in devices of these types, the use of an
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`a contact pad located in the interior of the printed circuit board
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`embedded component arrangement may help save space, may
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`in accordance with an embodiment of the present invention.
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`help allow board dimensions to be adjusted to satisfy design
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`FIG. 14 is an exploded perspective view showing how a
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`constraints ( e.g., to increase board thickness without unnec-
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`wire may be embedded within a printed circuit board in
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`10 essarily increasing the overall height of a printed circuit board
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`accordance with an embodiment of the present invention.
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`assembly, to decrease board thickness, etc.), may improve
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`FIG.15 is a top view ofa printed circuit board showing how
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`environmental sealing, may improve structural strength, etc.
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`a wire channel may be provided with strain relief features in
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`Manufacturability may also be enhanced ( e.g., by allowing
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`accordance with an embodiment of the present invention.
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`more components to be assembled in an integrated fashion,
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`FIG. 16 is a cross-sectional side view of a conventional
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`15 thereby reducing part counts).
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`dome switch without a protective housing.
`A cross-sectional side view of an illustrative printed circuit
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`FIG. 17 is a cross-sectional side view of a conventional
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`board with embedded components is shown in FIG. 1. In the
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`dome switch encased within a protective housing.
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`example of FIG. 1, switch 14 and integrated circuit 24 have
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`FIG. 18 is a cross-sectional side view of an illustrative
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`been embedded within printed circuit board 12. Printed cir-
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`printed circuit board with an integrated dome switch and
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`20 cuit board 12 may contain one or more layers. Components
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`embedded integrated circuit in accordance with an embodi­
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`that are embedded within printed circuit board 12 may be
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`ment of the present invention.
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`embedded within an interior cavity of board 12 or may be
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`FIG.19 is a top view of an illustrative electronic device that
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`embedded in a board recess (i.e., an opening that penetrates
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`includes a printed circuit board with embedded components
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`only partway into board 12). Integrated circuit 12 represents
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`in accordance with an embodiment of the present invention.
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`25 an example of a component that is embedded within an inter­
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`FIG. 20 is a flow chart of illustrative steps involved in
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`nal cavity in board 12. Switch 14 represents an example of a
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`forming printed circuit boards with embedded components in
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`component embedded in a recess in board 12.
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`accordance with an embodiment of the present invention.
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`As shown in FIG. 1, switch 14 may be a packaged dome
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`FIG. 21 is a cross-sectional side view of an illustrative
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`switch having a housing that encloses dome switch member
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`printed circuit board with an integrated dome switch and
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`30 22. This type of packaged dome switch is sometimes referred
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`embedded integrated circuit that may include a stiffener in
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`to as a "tact" (tactile) switch. Other types of switches may be
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`accordance with an embodiment of the present invention.
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`embedded within printed circuit boards if desired. Switch 14
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`FIGS. 22A and 22B are perspective views of illustrative
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`may have a structure such as structure 18 that a user may
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`stiffeners that may provide mechanical support for a dome
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`actuate with the tip of finger 16 or other external object. When
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`switch that is integrated into a printed circuit board of the type
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`35 finger 16 is pressed downwards in direction 20, member 18
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`shown in FIG. 21 in accordance with embodiments of the
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`may move downwards to compress domes switch member 22
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`present invention.
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`and thereby close switch 14.
`The recesses in which components such as switch 14 are
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`mounted may have the shapes of circles, squares, elongated
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`This relates to substrates for mounting components. The
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`40 groove-like shapes, etc. Interior openings (buried cavities) in
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`substrates may be, for example, printed circuit board sub­
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`board 12 may be cube-shaped or may have other suitable
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`strates. The components that are mounted may include elec­
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`shapes. In some arrangements, more complex openings in
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`trical components such as switches and wires and may
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`printed circuit board 12 may be formed. For example,
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`include mechanical components such as supports or housing
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`grooves, via-shaped recesses, interior cavities, and other
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`structures. Illustrative arrangements in which electrical com­
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`45 openings may be combined to help attach and mount more
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`ponents are mounted using printed circuit board substrates
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`complex structures such as wires or components that require
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`are sometimes described herein as an example.
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`venting ( e.g., microphones and speakers).
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`Components may be embedded in printed circuit board
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`Printed circuit board 12 may include one or more layers of
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`substrates by forming grooves or other recesses in the surface
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`dielectric and one or more layers of conductor. Typical
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`of a board. Components may also be embedded within the
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`50 printed circuit boards may have core layers that are formed
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`interior of a printed circuit board. Combinations of these
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`from dielectrics. Examples of suitable materials that may be
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`approaches may be used if desired.
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`used in forming a printed circuit board include dielectrics
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`Grooves and other openings in a printed circuit board may
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`such as fiberglass-filled epoxy (e.g., in a rigid printed circuit
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`be formed by milling or machining using drills routers or
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`board) and polyimide ( e.g., in a flexible printed circuit board
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`other mechanical tools or using laser machining equipment.
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`55 of the type sometimes referred to as a flex circuit). For
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`For example, lasers may be used to drill vias in printed circuit
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`example, printed circuit boards may be formed from FR-2
`boards.
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`(phenolic cotton paper), FR-3 ( cotton paper and epoxy), FR-4
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`The components that are embedded in a printed circuit
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`(woven glass and epoxy), FR-5 (woven glass and epoxy),
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`board may include switches, wires, integrated circuits, con­
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`FR-6 (matte glass and polyester), G-10 (woven glass and
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`nectors, microphones, speakers, light-emitting diodes and
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`60 epoxy), CEM-1 (cotton paper and epoxy), CEM-2 (cotton
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`other components that can serve as displays and status indi­
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`paper and epoxy), CEM-3 (woven glass and epoxy), CEM-4
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`cators, or other suitable structures and electrical components.
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`(woven glass and epoxy), CEM-5 (woven glass and polyes­
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`Configurations in which components such as switches, wires,
`ter), paper impregn ated with phonolic resin, polystyrene,
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`integrated circuits, and microphones are embedded in printed
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`polyimide, polytetrafluoroethylene (PTFE), plastic, other
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`circuit boards are sometimes described herein as an example.
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`65 polymers, ceramics, or other suitable dielectrics.
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`This is merely illustrative. Any suitable components may be
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`In multilayer printed circuit boards, core layers may be
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`embedded in a printed circuit board if desired.
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`attached to each other using attachment layers such as layers
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`DETAILED DESCRIPTION
`
`Ex.1012
`APPLE INC. / Page 25 of 30
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`US 8,339,798 B2
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`6
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`fiber and resin). of prepreg (i.e., pre-impregn ated layers of
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`To accommodate components of different shapes and
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`Layers of copper or other conductive materials may be
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`sizes, it may be desirable to form a variety of different open­
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`formed on the surfaces of the printed circuit board core layers
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`ings in the materials that make up printed circuit board
`12.
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`and prepreg layers. For example, a core layer may have upper
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`These openings may take the form of squares, rectangles,
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`and lower surfaces that are covered with a layer of metal such 5
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`circles, shapes with curved and straight sides, elongated
`as copper.
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`groove-like and slot-like shapes, etc. A perspective view of a
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`A cross-sectional side view of printed circuit board 12
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`printed circuit board showing some of the types of openings
`printed showing how board 12 may be formed from multiple
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`that may be formed in the layers of the printed circuit board is
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`circuit board core layers C alternated with interposed layers
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`shown in FIG. 3.As shown in FIG. 3, printed circuit board 12
`10 of prepreg P is shown in FIG. 2. The core layers may be
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`may include multiple layers such as layers 12A, 12B, and
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`attached to the prepreg layer and to each other by curing the
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`12C. Only three layers are shown in FIG. 3, but, in general,
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`prepreg ( e.g., by application of heat and pressure while the
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`one board 12 may have any suitable number of layers ( e.g.,
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`layers are in proper lateral alignm ent).
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`layer, two layers, three layers, four layers, more than four
`As shown in the example of FIG. 2, printed circuit board 2
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`twenty layers,fewer than 15 layers, more than twenty layers,
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`may include multiple printed circuit core layers C each of
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`be alter­etc.). Layers 12A, 12B, and 12C may, for example,
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`which includes a printed circuit board core dielectric layer 30
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`nating layers of prepreg and core material ( e.g., FR4) or other
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`(e.g., FR4) interposed between respective upper and lower
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`suitable dielectric layers and may have associated patterned
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`of core surfaces metal layers of copper on the 32 ( e.g., layers
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`metal layers for forming interconnects. The metal layers are
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`prepreg dielectric 30). Each prepreg layer P may include 26.
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`20 not shown in FIG. 3 to avoid over-complicating the drawing.
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`the The exposed upper and lower surfaces of board 12 (i.e.,
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`Openings 40 may be formed in layers 12A, 12B, and 12C.
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`upper surface of the upper most prepreg layer P and the lower
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`through the layer in which Openings 40 may pass completely
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`surface of the bottommost prepreg layer Pin the orientation of
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`they are formed (see, for example, square opening 40D,
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`FIG. 2) may be coated with patterned conductor (e.g., pat­
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`which passes completely through layer 12A) or may be pro-
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`The may be used if desired. terned metal 28). Other layups
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`25 vided in the form of recesses that pass only partway through
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`number of layers and the makeup of the layers in printed
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`a layer ( see, for example, groove 40C, which passes through
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`circuit board 12 of FIG. 2 is merely illustrative.
`the upper half of layer 12C, but which does not pass through
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`The metal layers of printed circuit board such as layers
`28
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`components the lower half of layer 12C). To accommodate
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`hography, laser etch­and 32 may be patterned using photolit
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`that require openings through more than one layer, openings
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`ing, foil stamping, screen printing, pad printing, shadow
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`30 in respective layers can be aligned and stacked one on top of
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`masking, or other suitable conductor patterning techniques.
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`the next ( see, for example, laterally aligned openings 40A and
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`by In a typical scenario, copper layers 32 may be patterned
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`40B, which are formed in adjacent layers 12A and 12B).
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`screen printing a masking layer onto the surface of each layer,
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`When printed circuit board 12 is formed by laminating layers
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`etching to remove unprotected metal, and removing the
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`12A, 12B, and 12C together, openings 40A and 40B will
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`masking layer. The patterned conductive material oflayers
`28
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`35 combine to form a larger opening (i.e., an opening with a
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`and 32 may be used to form sign al lines, contact pads, and
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`larger vertical dimension) than would be possible by forming
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`other conductive structures. These structures, which are
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`a hole in a single one of these layers.
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`sometimes collectively referred to as interconnects, may be
`The components that are embedded in printed circuit board
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`formed on the upper surface and lower surface of board 12
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`compo-12 may be stand-alone components. For example,
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`and in interior layers of board 12.
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`40 nents such as packaged integrated circuit die and packaged
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`Vertical conductive structures called vias may be used to
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`that switches may be embedded in board 12. The components
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`electrically connect layers of interconnects in board 12. As
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`are embedded in printed circuit board fabri­12 may also be
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`shown in FIG. 2, different types ofvias 34 may be formed in
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`cated using an integrated approach (i.e., by forming parts of
`board 12.
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`board from the printed circuit for the components the housing the within Vias such as via Vl that are contained entirely
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`material itself). do not make direct electrical 45 interior of board 12 and that
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`connection to the outside layers of board 12 are sometimes
`An example of an arrangement that involves the mounting
`
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`
`
`referred to as buried vias. In the example of via FIG. 2, buried
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`of stand-alone components is shown in FIG. 4. As shown in
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`lower copper layers on the Vl is used to connect the upper and
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`in printed FIG. 4, tact switch 14 may be embedded in a recess
`
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`lowermost core layer C of board 12.
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`in circuit circuit board 12 and integrated 24 may be mounted
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`conductive Vias such as via V2 that are used to connect
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`50 an internal cavity in printed circuit board 12. Tact switch 14
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`structures on an exterior surface of board 12 to an interior
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`may have conductive terminals (leads) 42. Vias 34 such as
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`referred to as conductive layer in board 12 are sometimes
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`laser-drilled vias or other vias may be used to form electrical
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`blind vias. In the example of FIG. 2, blind via V2 is used to
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`connections to terminals 42 and contact pads 44 on integrated
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`connect the lowermost surface of board 12 to one of the
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`such as interconnects circuit 24. Interconnects 46 may be
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`copper layers on the lowermost core layer in board 12. Vias
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`55 used to form electrical routing pathways for printed circuit
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`such as via V3 that pass through the entire thickness of board
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`such as con­board 12 (e.g., to interconnect metal structures
`
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`vias. As shown in 12 are sometimes referred to as through
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`tacts 44, vias 34, and terminals 42).
`FIG. 2, via V3 (and the other vias 34 in board 12) may be
`a microcon­Integrated circuit 24 may be a microprocessor,
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`coated with an interior conductive layer such as plated copper
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`troller, an audio chip, an application-specific integrated cir-
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`layer 36. As illustrated by laser beam 38 and laser-drilled via
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`60 cuit, or other integrated circuit. If desired, discrete electrical
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`V 4, vias 34 can be formed by laser drilling. Vias can also be
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`components (e.g., resistors, inductors, capacitors, and tran­
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`formed using mechanical drilling (i.e., with a drill bit) or
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`sistors) may be mounted in internal cavities in printed circuit
`
`
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`other mechanical machining techniques. Via holes may be
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`
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`may be mounted in board 12 or multiple integrated circuits
`
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`filled using metal ( e.g., copper) plating techniques, by filling
`
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`internal cavities in printed circuit board types of 12. Different
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`
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`a via hole with conductive paste, by filling a via hole with
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`65 stand-alone components may also be embedded in printed
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`conductive adhesive, or by filling a via hole with other con­
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`
`
`circuit board The example 12 if desired. of FIG. 4 is merely
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`ductive material.
`illustrative.
`
`Ex.1012
`APPLE INC. / Page 26 of 30
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`US 8,339,798 B2
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`8
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`7
`As shown in FIG. 5, components such as microphones
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`pads such as solder pad 56, which may sometimes be referred
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`(e.g., microphone 50) may be embedded in printed circuit
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`to as contacts, contact pads, or interconnect structures, may
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`board 12 with other components such as switch 14 and inte­
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`be formed from patterned conductor layers in printed circuit
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`grated circuit 24. Interconnects such as horizontal intercon­
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`board 12 ( e.g., layers such as layers 32 of FIG. 2) or other
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`nect structures 46 and vias 34 may be used to interconnect
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`5 suitable conductive structures. Solder pads 56 may, for
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`terminals 44 on microphone 50 with terminals 44 on inte­
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`
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`example, be formed form copperor copper pla