(12) United States Patent
`Jochym et al.
`
`USOO6747217B1
`(10) Patent No.:
`US 6,747,217 B1
`(45) Date of Patent:
`Jun. 8, 2004
`
`(54) ALTERNATIVE TO THROUGH-HOLE-
`8/1970 Lohff ......................... 174/262
`3,524,960 A
`PLATING IN A PRINTED CIRCUIT BOARD
`3,660,726 A * 5/1972 Ammon et
`174/262
`5,290,970 A * 3/1994 Currie ......
`174/250
`(75) Inventors: Daniel A. Jochym, Downingtown, PA EA : E. S. it al... 75.
`S. Robert H. Fix, Schwenksville,
`5,761,050 A
`6/1998 Archer ....................... 361/791
`(US)
`6,011,222 A * 1/2000 Sekiya et al. ............... 174/266
`6.255,601 B1
`7/2001 Burkhart ..................... 174/255
`(73) ASSignee: try Corporation, Blue Bell, PA
`6,333,471 B1 * 12/2001 Nojioka ...................... 174/261
`
`loC C all. . . . . . . . . . . . . . . . . .
`
`Y/ - / 2
`
`:
`
`(*) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`(21) Appl. No.: 09/989,820
`(22) Filed:
`Nov. 20, 2001
`(51) Int. Cl." ........................... H01R 12/04; H05K 1/11
`(52) U.S. Cl. ........................................ 174/265; 174/266
`(58) Field of Search ................................. 174/265, 267,
`174/262-264, 266; 29/842, 843, 844, 845;
`361/792, 793, 794, 803
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`sk -
`
`cited by examiner
`
`Primary Examiner David A. Zarneke
`Assistant Examiner Jeremy Norris
`(74) Attorney, Agent, or Firm Michael B. Atlass; Mark T.
`Starr
`(57)
`ABSTRACT
`A printed circuit board (PCB) comprises a number of
`electrically conductive layers. Instead of coating, or plating,
`a PCB through-hole with an electrically conductive material
`to form a via (for the purpose of connecting together signal
`paths across the electrically conductive layers)-the via is
`formed by placing a conductive Stake, or conductive pin, in
`the through-hole.
`
`2,752,580 A * 8/1956 Shewmaker ................ 174/262
`
`6 Claims, 10 Drawing Sheets
`
`conductive
`layer \-
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`insulating r S:
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`signal path
`30
`
`conductive stakes
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`
`
`
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`
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`
`bottorn side
`
`conductive stake
`diameter 504
`
`- polygonal shape
`
`conductive stake 505
`
`
`
`insertion
`direction 501
`
`N- taper 508
`
`Y
`through-hole diameter 524
`
`Cree Exhibit 1010
`Page 1
`
`

`

`U.S. Patent
`U.S. Patent
`
`US 6,747,217 B1
`US 6,747,217 B1
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`Cree Exhibit 1010
`Page 2
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`Cree Exhibit 1010
`Page 2
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`

`

`U.S. Patent
`
`Jun. 8, 2004
`
`Sheet 2 of 10
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`Cree Exhibit 1010
`Page 3
`
`

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`U.S. Patent
`
`Jun. 8, 2004
`
`Sheet 3 of 10
`
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`
`Cree Exhibit 1010
`Page 4
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`

`

`U.S. Patent
`
`Jun. 8, 2004
`
`Sheet 4 of 10
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`Cree Exhibit 1010
`Page 5
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`

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`U.S. Patent
`
`Jun. 8, 2004
`
`Sheet 5 of 10
`
`US 6,747,217 B1
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`
`
`Cree Exhibit 1010
`Page 6
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`

`

`U.S. Patent
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`Jun. 8, 2004
`
`Sheet 6 of 10
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`
`Cree Exhibit 1010
`Page 7
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`

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`U.S. Patent
`
`Jun. 8, 2004
`
`Sheet 7 of 10
`
`US 6,747,217 B1
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`Cree Exhibit 1010
`Page 8
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`Cree Exhibit 1010
`Page 8
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`

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`U.S. Patent
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`Jun. 8, 2004
`
`Sheet 8 of 10
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`US 6,747,217 B1
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`
`Cree Exhibit 1010
`Page 9
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`

`

`U.S. Patent
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`Jun.8, 2004
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`Sheet 9 of 10
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`US 6,747,217 B1
`US 6,747,217 B1
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`Cree Exhibit 1010
`Page 10
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`Cree Exhibit 1010
`Page 10
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`

`

`U.S. Patent
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`Jun. 8, 2004
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`Sheet 10 Of 10
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`US 6,747,217 B1
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`Cree Exhibit 1010
`Page 11
`
`

`

`1
`ALTERNATIVE TO THROUGH-HOLE
`PLATING IN A PRINTED CIRCUIT BOARD
`
`US 6,747,217 B1
`
`FIELD OF THE INVENTION
`This invention relates generally to manufacturing and,
`more particularly, to printed circuit boards (PCBs).
`BACKGROUND OF THE INVENTION
`Aprinted circuitboard (PCB) (also referred to as a printed
`wiring board (PWB), or a PC Larninate (PC Lam)) provides
`a mechanism for implementing a circuit design (i.e., the
`interconnection of electrical devices and components). A
`PCB may be “single layer,” “double layer,” or “multi
`15
`layer'-each of which refers to the number of electrically
`conductive layers. A multi-layer board comprises alternating
`layers of conductive material and electrically insulating
`material bonded together. (AS used herein, terms of the form
`“conductive” and “insulating” refer to the properties of
`electrical conduction and electrical insulation, respectively.)
`In order to connect Signal paths from one conductive layer
`to another conductive layer, holes (or through-holes) are
`drilled through a PCB and are subsequently coated, or
`plated, with a conductive Substance (there are a variety of
`known techniques for through-hole-plating). These plated
`through-holes are also referred to as “vias.” In high-density
`circuit designs, the number of components-and the result
`ing Signal paths interconnecting the components-typically
`require use of multi-layer boards with thousands of Vias. (It
`should be noted that there are also other types of holes
`drilled into a PCB, e.g., “component holes” for receiving the
`pins of a Surface mount component.)
`Each through-hole comprises a length (which corresponds
`to the thickness of the PCB across all of the layers) and a
`diameter. In general, in order to plate the through-hole, the
`through-hole must have a minimum diameter that is a direct
`function of the thickness of the PCB, which itself is deter
`mined as a function of the design of each layer. (Layers do
`not have to be the Same thickness, and can vary in thickness
`as a function of the electrical characteristics desired. In
`addition, this minimum through-hole diameter may also be
`a function of the particular plating technique, which is not
`described herein.)
`SUMMARY OF THE INVENTION
`Obviously, the design of a PCB-and the number of
`conductive layers to use-is directly influenced by the
`particular circuit design. However, we have also observed
`that as the decision is made to increase the thickness of the
`PCB-there may be a concomitant increase in the amount of
`Space, i.e., the minimum diameter, required by through
`holes-space that cannot be used to route Signals.
`Therefore, and in accordance with the invention, instead
`of coating, or plating a through-hole with a conductive
`material to form a via-the via is formed by placing a
`conductive Stake in the through-hole for electrically cou
`pling foils disposed on at least two electrically conductive
`layers together. Thus, as the thickness of a PCB increases,
`the diameter of the individual through-holes Stay the same
`and the amount of Space taken up by through-holes does not
`change.
`In an embodiment of the invention, a conductive Stake is
`inserted into a through-hole of a PCB for the purpose of
`forming a Via. The conductive Stake comprises, e.g., a
`phosphor bronze material, and is gold-over-nickel plated.
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`The length of the conductive Stake is at least as long as the
`distance between two conductive layers of the PCB. A
`diameter of the conductive Stake is approximately greater
`than, or equal to, the diameter of the through-hole.
`
`BRIEF DESCRIPTION OF THE DRAWING
`FIGS. 1 and 2 show a portion of a cross-section of a
`printed circuit board Such that the conductive layers are
`coupled together in accordance with the principles of the
`invention;
`FIGS. 3, 4, 5 and 6 show other illustrative embodiments
`of the invention;
`FIG. 7 shows another illustrative embodiment of a con
`ductive Stake in accordance with the principles of the
`invention;
`FIG. 8 shows another illustrative embodiment of a con
`ductive Stake in accordance with the principles of the
`invention;
`FIG. 9 shows another illustrative use of the inventive
`concept, and
`FIG. 10 shows an illustrative method for inserting con
`ductive Stakes.
`
`DETAILED DESCRIPTION
`FIGS. 1 and 2 show a portion of a cross-section of a
`printed circuit board (PCB) such that signal paths on dif
`ferent conductive layers are electrically coupled together in
`accordance with the principles of the invention. Other than
`the inventive concept, the elements shown in FIGS. 1 and 2
`are well known and will not be described in detail. For
`example, techniques for forming a through-hole are well
`known and not described herein (e.g., drilling of a through
`hole is performed by computer numerical control (CNC)
`drilling equipment and tungsten-carbide drills, laser abla
`tion; etc., as known in the art). As such, familiarity with PCB
`construction techniques is assumed. For the purposes of this
`description, the term multi-layer also refers to double layer
`boards. As used herein, the term “conductive layer” refers to
`any trace (or foil) of conductive material placed upon an
`insulating layer for providing a pathway for an electrical
`Signal.
`Turning to FIG. 1, a top view of a PCB 50 is shown. PCB
`50 comprises a length 180 and a width 185 and also
`comprises a number of through-holes as represented by
`circles. (It should be noted that a PCB can comprise thou
`sands of through-holes.) One of these through-holes, 125, is
`illustratively shown in a cross-section view of portion 100 of
`PCB 50. Also shown is an illustrative signal path 101 (as
`represented by the thicker black line). PCB portion 100
`comprises four conductive layers (1, 3, 5 and 7) as repre
`Sented by the stippling, and three insulating layers (2, 4 and
`6) as represented by the diagonal cross-hatching. FIG. 1 is
`not to Scale. In this example, it is assumed that illustrative
`Signal path 101 should appear on conductive layerS 1, 3, 5,
`and 7 as represented by the thicker black line (which could
`be viewed as the foil placed on each conductive layer for
`signal path 101). An illustrative through-hole 125 has been
`formed in PCB portion 100 for the purpose of coupling the
`foil on each of the conductive layers together. Through-hole
`125 has a length 126 (which also corresponds to the thick
`ness of PCB portion 100) and a diameter 124. (A common
`Size for a diameter of a through-hole is in the range of 10 to
`25 mils (thousandths of an inch).) As can be observed from
`FIG. 1, a conductive stake (other equivalent terms are, e.g.,
`conductive insert, conductive pin, conductive sleeve, etc.)
`
`Cree Exhibit 1010
`Page 12
`
`

`

`US 6,747,217 B1
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`105 is arranged for insertion into through-hole 125. Con
`ductive Stake 105 has a conductive plating (e.g., gold-over
`nickel plating) as represented by the thicker black lines, a
`length approximating length 126, and a diameter greater
`than or equal to diameter 124 (described further below).
`Turning now to FIG. 2, this figure shows the arrangement
`of conductive stake 105 in PCB portion 100 after insertion
`in through-hole 125. As can be observed from FIG. 2, and
`in accordance with the inventive concept, a via has been
`formed for electrically connecting conductive layerS 1, 3, 5
`and 7 together So that electrical signals transmitted on Signal
`path 101 appears on all 4 conductive layers.
`FIG. 3 illustrates another embodiment of the inventive
`concept. A cross-section view of a portion 200 of a PCB is
`shown for an illustrative through-hole 225. PCB portion 200
`comprises five conductive layers (1, 3, 5, 7 and 9) as
`represented by the stippling; and four insulating layers (2, 4,
`6 and 8) as represented by the diagonal cross-hatching. FIG.
`3 is not to scale. An illustrative through-hole 225 has been
`formed in PCB portion 200 for the purpose of coupling at
`least Some of the conductive layers together. Through-hole
`225 has a length 226 (which also corresponds to the thick
`ness of PCB portion 200) and a diameter 224. In this
`example, it is assumed that traces for a signal path 201 (as
`represented by the thicker black line) on conductive layers
`1 and 5 must be coupled together. As can be observed from
`FIG. 3, a conductive stake 205 is inserted into through-hole
`225 for forming a via for electrically connecting the foils on
`conductive layerS 1 and 5 together. In this example, the
`length 204 of conductive stake 205 is less than length 226
`and the diameter is greater than or equal to diameter 224
`(described further below). It should also be noted that the
`inventive concept is applicable to a “blind-via” This is
`shown in FIG. 4. Like numbers indicate similar elements
`and are not described further. In FIG. 4, conductive stake
`205 is inserted into hole 245 of PCB portion 250. As can be
`observed from FIG. 4, hole 245 does not completely go
`through PCB portion 250. Upon the insertion of conductive
`Stake 205 a “blind via is formed.
`FIG. 5 illustrates another embodiment of the inventive
`concept. A cross-section view of a portion 300 of a PCB is
`shown for an illustrative through-hole 325. PCB portion 300
`comprises five conductive layers (1, 3, 5, 7 and 9) as
`represented by the stippling; and four insulating layers (2, 4,
`6 and 8) as represented by the diagonal crosshatching. FIG.
`5 is not to scale. An illustrative through-hole 325 has been
`formed in PCB portion 300 for the purpose of coupling at
`least Some of the conductive layers together. Through-hole
`325 has a length 326 (which also corresponds to the thick
`ness of PCB portion 300) and a diameter 324. In this
`example, it is assumed that traces for a signal path 301 (as
`represented by the thicker black line) on conductive layers
`1 and 3 must be coupled together. In addition, it is assumed
`that traces for a signal path 302 (as represented by the
`thicker black line) on conductive layers 7 and 9 must be
`coupled together. As can be observed from FIG. 5, a
`conductive stake 305 is inserted into through-hole 325 from
`the topside of PCB portion 300 for forming a via for
`electrically connecting the foils on conductive layerS 1 and
`3 together. Similarly, a conductive stake 310 is inserted into
`through-hole 325 from the bottom side of PCB portion 300
`for forming a via for electrically connecting the foils on
`conductive layers 7 and 9 together. Thus, one through-hole
`is used to form multiple Vias. In this example, the length of
`conductive stake 305 is less than length 306 and the length
`of conductive stake 310 is less than length 311. Illustratively
`there is a space 320 between these conductive stakes. The
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`diameter of conductive stakes 305 and 310 are greater than
`or equal to diameter 324 (described further below). This
`ability to form multiple vias from one through-hole is useful
`in high-density component configurations since different
`Signal paths can now share the same through-hole. It should
`also be noted that the inventive concept is applicable to a
`“double-blind-vias.” This is shown in FIG. 6. Like numbers
`indicate Similar elements and are not described further. In
`FIG. 6, conductive stakes 305 and 310 are inserted into holes
`345 and 340 of PCB portion 350, respectively. As can be
`observed from FIG. 6, either of these holes do not com
`pletely go through PCB portion 350 and have diameter 324.
`Upon the insertion of conductive stakes 305 and 310 a
`“double-blind-via” is formed.
`Illustratively, it is assumed that a conductive Stake is Solid
`and comprises a phosphor bronze material, the Sides of
`which are gold-over-nickel plated. Such materials are well
`known. Similarly, a conductive Stake can be manufactured
`using known techniques, e.g., related to connector pins for
`connectors, etc., and as Such will not be described herein.
`Illustratively, the shape of the conductive Stakes illus
`trated in FIGS. 1 through 6 are cylindrical (as will be
`described below other shapes are possible, e.g., a polygon,
`Such as a Square, or rectangle). With respect to FIGS. 1
`through 6, the diameter of the conductive Stake should
`approximate, or be slightly larger than, the diameter of the
`through-hole (or hole in the case of a blind via or double
`blind via) to ensure mechanical Stability and provide an
`electrical interconnect. However, other shapes of conductive
`stakes are possible, such as shown in FIG. 7. The length of
`a conductive Stake is Selected as a function of the number of
`conductive layers that need to be coupled together (thus,
`length is not specified in FIG. 7). In this example, the length
`of conductive Stake 405 is, approximately, less than or equal
`to the thickness of the respective PCB (not shown). To
`simplify insertion into a through-hole, conductive stake 405
`is shown as having a certain amount of tapering 408 in the
`direction of insertion direction 401. Tapering is not required
`for the inventive concept, as Such the amount of tapering is
`not specified. Conductive stake 405 is illustratively a circle
`(absent the tapered portion) and has a diameter 407. (Other
`shapes can be used, e.g., an ellipse.) Conductive Stake
`diameter 407 is less than or equal to the diameter of the
`through-hole. As can be observed from FIG. 7, fins 406 are
`attached to conductive stake 405. The purpose of these fins
`is to cut into the material of the PCB that forms the
`walls/sides of the through-hole. Thus, providing a mechani
`cal interconnect and, at the conductive layers, cutting into
`the foil, or copper etching, to provide an electrical intercon
`nect. Illustratively, if the diameter of the through-hole is 12
`mils, the conductive stake diameter 407 is approximately 12
`mils and each fin extends out 2 mils, Such that the overall
`diameter 409 is approximately 16 mils. (In this example, it
`should be noted that the fins are not diametrically opposite
`each other. AS Such, overall diameter 409 is less than 16
`mils.)
`Another illustrative shape for a conductive Stake is shown
`in FIG.8. As noted above, the length of a conductive stake
`is Selected as a function of the number of conductive layers
`that need to be coupled together (thus, length is not specified
`in FIG. 8). In this example, the length of conductive stake
`505 is, approximately, less than or equal to the thickness of
`the respective PCB (not shown). To simplify insertion into
`a through-hole, conductive stake 505 is shown as having a
`certain amount of tapering 508 in the direction of insertion
`direction 501. Tapering is not required for the inventive
`concept, as Such the amount of tapering is not specified.
`
`Cree Exhibit 1010
`Page 13
`
`

`

`US 6,747,217 B1
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`Conductive stake 505 is illustratively a polygonal shape
`(absent the tapered portion) and has a diameter 504. In this
`example, conductive Stake 505 is a pentagon (other geomet
`ric shapes can be used). Conductive stake diameter 504 is
`larger than through-hole diameter 524 (the through-hole is
`not actually shown in FIG. 8). This ensures a tight fit into the
`through-hole and that there will be a certain amount of “bite”
`into the material of the PCB from at least a number of the
`points of conductive stake 505. This “bite” ensures both
`mechanical Stability and, by biting into any foil on a
`conductive layer, an electrical interconnect. Here, a five
`sided polygon was selected for conductive stake 505 so that
`5 points are available for making contact with the Sides of
`the through-hole (though not all of the 5 points are required
`for contact). Illustratively, if the diameter of the through
`hole diameter 524 is 12 mils, the conductive stake diameter
`504 is 16 mills.
`AS described above, a conductive Stake is inserted into a
`hole of the PCB and substantially disposed within the PCB
`Such that little, if any portion, of the conductive Stake
`extends beyond a surface of the PCB. However, another
`illustrative use for a conductive stake is shown in FIG. 9,
`which illustrates a cross-section of a portion 700 of a PCB.
`A number of conductive stakes 705 have been placed in
`through-holes 725. In this 520 example, the conductive
`stakes 705 extend beyond a surface (e.g., the top) of the
`PCB. (It should be noted that the conductive stakes could
`extend out from one or more Surfaces (e.g., the top and
`bottom) of the PCB.) This allows another board, e.g.,
`interposer board 740 to be electrically and mechanically
`coupled to the PCB. In particular, interposer board 740
`comprises a number of conductive sleeves 745, each of
`which fit over a corresponding conductive Stake. Each
`conductive sleeve has a diameter Slightly larger than the
`diameter of a conductive Stake for allowing a press fit (in
`direction 721) of interposer board 740 to the PCB. In this
`example, interposer board 745 carries an application
`specific-integrated-circuit (ASIC) 750 that is solder
`mounted to the top of interposer board 740. This type of
`mounting allows ASIC 750 to be electrically coupled to
`signal paths (not shown) on the PCB. In the case where the
`PCB of FIG. 9 is, e.g., a mid-plane, this enables devices,
`such as represented by ASIC 750, to be directly coupled to
`the mid-plane.
`In terms of inserting a conductive stake(s) into a PCB
`anyone of a number of methods may be used. For example,
`each one can be done by hand. However, as known in the art
`a "pin insertion machine' was historically used to insert
`wire-wrap posts into a board (hence making a wire-wrap
`board). (In a wire-wrap board, actual wires are wrapped
`from one wire-wrap post to another wire-wrap post (using a
`Stitching machine) to form the signal paths.) This form of
`machine can be modified by those skilled in the art to insert
`conductive stakes into a PCB. Another method is shown in
`FIG. 10. This method is illustratively performed manually. A
`55
`number of conductive stakes 605 are initially inserted into
`corresponding through-holes 625 (the use of tapered con
`ductive Stakes would simplify the initial insertion process)
`of PCB 600. An insertion board 620 (e.g., a piece of metal
`having Suitable dimensions as illustrated in FIG. 10, e.g.,
`similar to PCB 600) is placed over conductive stakes 605
`and a force in direction 621 is applied to complete the
`insertion of the conductive Stakes.
`AS described above, the inventive concept provides an
`alternative to through-hole-plating Such that the amount of
`real estate taken up by a via is independent of the thickneSS
`of a particular PCB. Indeed, the inventive concept allows the
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`diameter of the Vias to be kept to a minimum. Thus, the idea
`allows one to maintain, if not increase, the routing density of
`Signal paths when the thickness of a PCB is increased,
`compared to that of a plated-through hole approach.
`The foregoing merely illustrates the principles of the
`invention and it will thus be appreciated that those skilled in
`the art will be able to devise numerous alternative arrange
`ments which, although not explicitly described herein,
`embody the principles of the invention and are within its
`Spirit and Scope. For example, consider the following.
`Although the inventive concept was described in the context
`of a particular type of conductive Stake, other types of
`conductive Stakes can be used, e.g., hollow ones. Also,
`although a rigid multi-layer board was illustrated above, the
`inventive concept is applicable to other types of PCBs, e.g.,
`flexible PCBs. In this case, the conductive stake may have
`to be mechanically fastened differently than described
`above, e.g., like a rivet, to ensure mechanical fastening.
`Similarly, although the inventive concept was described in
`the context of inserting the conductive Stake into the Via
`using a “preSS fit” for connecting the conductive Stake to the
`conductive layers, other types of connection methods may
`be used. For example, the conductive Stake could initially
`have a Smaller diameter than the through-hole Such that, e.g.,
`upon heating, the conductive Stake expands to fill the
`through-hole. In addition, it is not necessary that an entire
`PCB use the inventive concept. For example, a portion of a
`PCB, or different portions of a PCB, may use the inventive
`concept while other portions of the PCB use plated-through
`holes.
`What is claimed is:
`1. A multilayer printed circuit board with at least one
`through hole perpendicular to the plane of the layers of the
`multiplayer printed circuit board, Said multiplayer printed
`circuit board having at least four trace layers with foil
`conductors therein and non-conductive materials between
`each of Said four trace layers, Said multilayer printed circuit
`board having lodged within Said through hole two conduc
`tive Stakes, each of Said two conductive Stakes having an
`inner Side, the inner Side of each Stake directed toward a
`center of Said through hole, there being a space within Said
`through hole Separating Said inner sided of Said two Stakes,
`Said two conductive Stakes providing electrical contact to at
`least two conductive foils in two of Said trace layerS Sepa
`rated by a layer of non-conductive material, thus establish
`ing by each Said conductive Stake an electrical pathway
`between said foils.
`2. The circuit board of claim 1, wherein the conductive
`Stake has a longitudinal polygonal shape Such that at least
`one corner of Said polygonal shape when inserted into Said
`through hole extend beyond an internal diameter So as to
`establish electrical contact with the foils.
`3. A multilayer printed circuit board with at least two
`partial through holes, aligned in a perpendicular axis to the
`plane of the layers of the multiplayer printed circuit board,
`Said multilayer printed circuit board having at least four
`trace layers with foil conductors therein and non-conductive
`materials between each of Said four trace layers, Said mul
`tilayer printed circuit board having lodged within each Said
`partial through hole a conductive Stake, each of Said two
`conductive Stakes having an inner Side, the inner Side of each
`stake directed toward the partial through hole in which the
`other conductive Stake is lodged, there being at least a
`portion of a layer of Said multilayer circuit board Separating
`Said inner Sides of Said two conductive Stakes, Said two
`conductive Stakes providing electrical contact to at least two
`conductive foils in two of Said trace layerS Separated by a
`
`Cree Exhibit 1010
`Page 14
`
`

`

`US 6,747,217 B1
`
`7
`layer of non-conductive material, thus establishing by each
`Said conductive Stake an electrical pathway between said
`foils on opposing sides of said multilayer circuit board,
`separated by said at least a portion of a layer.
`4. The circuit board of claim 3 wherein at least one of the 5
`- 0
`conductive Stakes has a longitudinal polygonal shape Such
`that at least one corner of Said polygonal shape when
`inserted into Said partial through hole extend beyond an
`internal diameter of Said partial through hole So as to
`establish electrical contact with the foils.
`5. A printed circuit board comprising:
`at least three layers of material, Such that two of the layers
`of material are electrically conductive and the third
`layer is an electrical insulator and wherein the insulat
`ing layer is disposed between the conductive layers; 15
`and
`
`1O
`
`8
`at least one conductive Stake inserted into a Substantially
`round through hole of a certain diameter established in
`the printed circuit board for forming a via or electri
`cally connecting foils from the two conductive layers
`t
`ogether;
`
`wherein the conductive Stake has a filled polygonal shape
`when Viewed in cross-section Such that at least one
`corner of Said polygonal shape when inserted into Said
`through hole extend beyond Said certain diameter So as
`to establish contact with the foils for forming the via.
`6. The circuit board of claim 5 wherein said polygonal
`shape is a pentagon.
`
`Cree Exhibit 1010
`Page 15
`
`