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`
`US 2()[)4(X)16939A1
`
`(19) United States
`(12) Patent Application Publication (10) Pub. N0.: US 2004/0016939 A1
`
`Akiba et al.
`(43) Pub. Date:
`Jan. 29, 2004
`
`(54)
`
`I‘ZNCAPSUIATION 01“ A STACK 0F
`SEMICONDUCTOR DICE
`
`Publication Classificaltiun
`
`(70)
`
`lnuunlors: Masayuki Akiha, [buraki—kun (JP);
`Kinya lchiknwa, lharaki-kcn (JP); .Iirn
`Kubota. [hurnki-kcn (J 1’}: Ta kasili
`Kllnnlmuln. lbaraki-kcn {JP}
`
`('forrcgpmldcncc Address:
`BIAKI'ZLY summon: TAYLOR & ZAFMAN
`[2400 WILSHIRE BOULEVARD, SEVIEN'I‘H
`FLOOR
`LOS ANGELES, CA 90025 (US)
`
`(21) Appl. Nu:
`
`1(|.r’206,007
`
`(22)
`
`Filed:
`
`Jul. 26, 2002
`
`Int. Cl.7 ..................................................... Hill], 29!?4
`(5|)
`
`(52) US. Cl.
`............ 257;“126
`
`(57)
`
`v ‘
`.
`..
`A85 l ML!
`
`Syslcrns and methods liar encapsulating a slack (If StilTliL‘Ol'l-
`duclnr dice are described. A stack of semiconductor slice
`may be formed for example by attaching die to flexible
`printed circu it supports attached 10 frames and stacking, the
`supporls, and than encapsulated by flowing a liquid uncap-
`sulanl around [he slack 01‘ LiiL‘U and solidifying lhu liquid
`cncapsulnnl. The die supports. may contain cncapsulanl lluw
`openings, such as rcclangular slits,
`thal allow the liquid
`cncapsulanl lo flow around [he slack (if dice.
`
`INTCQRATED cam 11‘ DENCE
`(mum-4C. ruminants» and;
`or: SEmtconmmR but:
`goo
`
`Eu (”331.0HT
`
`SAMSUNG EXHIBIT 1014
`SAMSUNG EXHIBIT 1014
`Samsung v. Trenchant
`Samsung v. Trenchant
`Case IPR2021-00258
`Case |PR2021-00258
`
`

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`DICE BASED ON DEFECT
`INFORMATION
`
`ATTACH LOGIC DIE TO
`SUPPORT
`
`TEST LOGIC DIE FOR
`DEFECTS
`
` FORM STACK OF MEMORY
`
`STACK LOGIC DIE RELATIVE
`TO STACK OF MEMORY DICE
`BASED ON DEFECT
`INFORMATION
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`LOGIC AND MEMORY DICE
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`Jan. 29, 2004 Sheet 17 0f 17
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`US 2004/0016939 A1
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`M FIGUKE
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`ENCAPSuLATEbStacK
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`US 2004/0016939 A1
`
`Jan. 29, 2004
`
`ENCAPSUIATION OF A STACK 0F
`SEMICONDUCTOR DICE
`
`BACKGROUND
`
`[0001]
`
`1. Field
`
`[0002] An embodiment of the invention relates to a device
`having more than one semiconductor die. More particularly,
`the embodiment relates to a device having an encapsulated
`stack of semiconductor dice, and to a method for forming the
`device.
`
`[0003]
`
`2. Background
`
`[0004] Semiconductor based electronic components of
`many modern electrical systems are often provided as mul-
`tiple die packages wherein two or more electrically con-
`nected semiconductor die are packaged together. FIC. 1
`shows a prior art package 100 containing a stack of sepa-
`rately molded silicon die. The package contains a
`first
`substrate 110, a first silicon die 120, a first epoxy molding
`compound 130 globbed over the first die, a second substrate
`150, a second silicon die 160, a second epoxy molding
`compound 170 globbed over the second die, and solder balls
`1401:) provide electrical connection between the first and the
`second silicon die. The second die is stacked over the first
`die after the molding compounds have been separately
`globbed over the dice.
`
`[0005] Stacked die packages, such as the one shown, offer
`a number of advantages. One advantage is an ability to
`separate the functions on each semiconductor (lie. For
`example, the first die 120 may contain primarily logic and
`the second die 160 may contain primarily memory. This
`separation of functions may simplify fabrication and may
`improve fabrication yields, inasmuch as the yields of logic
`die are often less than those of memory die. A further
`advantage of such packages is that they are compact, have
`high circuit density, and have low footprint area. This makes
`these packages particularly useful for providing electronic
`components and functions for compact electrical systems,
`such as cellular phones and the like. For these and other
`reasons, stacked semiconductor dice packages are favored
`[or many modern and commercially significant electronic
`devices.
`
`[0006] Unfortunately, the prior art package 100 and the
`existing methods for fabricating such a package have a
`number of disadvantages. One significant disadvantage is
`that
`the fabrication method is generally inefficient and
`contains a number ot'unnecessary operations. In fabricating
`the prior art package, each of the die are molded separately
`to their respective substrates. That is, molding compound
`130 is globbed over the first die 12/0 attached to the first
`substrate 110, and then, separately, molding compound 170
`is globbed over the second die 160 attached to the second
`substrate 150. Performing these moldings separately often
`involves either
`the use of additionalt‘replicnte molding
`equipment. which may increase the manufacturing costs, or
`else a decrease in manufacturing throughput if the same
`equipment is used. Additionally, numerous handling opera-
`tions may need to be performed by operators or machines in
`order to move the multiple attached die into and out of the
`molding equipment. Also as a consequence of the separate
`molding operations,
`the thickness and regularity of the
`thickness of the molding compounds 130 and 170 are
`
`generally insuflicient to allow electrical connection through
`the solder halls. Accordingly,
`in the prior art fabrication
`methods, planarization operations are often used to planarize
`the top surface ofthe molding compounds at heights that are
`similar to the height of the solder balls. Another operation
`that is often performed in the prior art fabrication method is
`application of an adhesive to adhere the first molding
`compound 130 to the second support 150, since the molding
`compounds are hardened before contact and provide no
`mechanical connection. Each of these operations may add to
`the overall cost of packaging the device.
`
`[0007] Additionally, even after planarization, the molding
`compounds often significantly increase the overall thickness
`of the package. Often, this will not be desired, particularly
`if the package is to be used in a cellular phone or other small
`device.
`
`BRIEF DESCRIPTION OF THE SEVERAI..
`VIEWS OF THE DRAWINGS
`
`[0008] The invention may best be understood by referring
`to the following description and accompanying drawings
`that are used to illustrate embodiments of the invention. In
`the drawings:
`
`[0009] FIG. 1 shows a cross-sectional view of a package
`that contains a stack of separately molded silicon die.
`
`[0010] FIG. 2 shows a cross—sectional view of an inte—
`grated circuit dcvice containing an encapsulated stack of
`dice, according to one embodiment of the present invention.
`
`[0011] FIG. 3 shows a top view of a die support that
`includes a rigid frame and a flexible sheet, according to one
`embodiment of the present invention.
`
`[0012] FIG. 4 shouts a top view of a die attached to the
`assembled support of FIG. 3, according to one embodiment
`of the present invention.
`
`in un-
`top view of a support
`[0013] FIG. 5 shows a
`assembled and assembled formaLs, according to one embodi-
`ment of the present invention.
`
`[0014] FIG. 6 shows a side—perspective view of a die on
`a rigid or inflexible support, according to one embodiment
`of the present invention.
`
`[0015] FIG. 7 shows a top view of a support containing
`encapsulant
`llow slits formed at opposite sides of the
`intended positions of a set of dice. according to one embodi-
`ment of the present invention.
`
`[0016] FIG. 8 shows a method for encapsulating a stack of
`dice, according to one embodiment of the present invention.
`
`[0017] FIG. 9 shows a cross-sectional view of a die
`attached to a support comprising a flexible sheet held in a
`rigid frame, according to one embodiment of the present
`invention.
`
`[0018] FIG. 10 shows a cross-sectional view of a stack of
`three dice attached to their respective supports and stacked
`with the use of an alignment system, according to one
`embodiment of the present invention.
`
`[0019] FIG. 11 shows an encapsulation system to encap-
`sulate a stack of dice, according to one embodiment of the
`present invention.
`
`

`

`US 2004/0016939 A1
`
`Jan. 29, 2004
`
`[0020] FIG. 12 shows a cross-sectional view of the stack
`of dice of FIG. 10 placed in an encapsulation chamber,
`according to one embodiment of the present invention.
`
`[0021] FIG. 13 shows a cross~sectional view of the stack
`of dice of FIG. 12 after encapsulation, according to one
`embodiment of the present invention.
`
`[0022] FIG. 14 shows a cross-sectional view of the encap-
`sulated stack of dice of FIG. 13 after removal from the
`encapsulation chamber, according to one embodiment of the
`present invention.
`
`[0023] FIG. 15 shows a cross-sectional view of an encap-
`sulated stack ofdice device formed by removing the release
`tape and excess encapsulant and support materials from the
`periphery of the stack of dice of FIG. 14, according to one
`embodiment of the present invention.
`
`[0024] FIG. 16 a method for encapsulating stacked logic
`and memory dice, according to one embodiment of the
`present invention
`
`[0025] FIG. 17 shows an encapsulated stack of dice
`contained within an electrical system, according to one
`embodiment of the present invention.
`
`DETAILED DESCRIPTION
`
`[0026] Described herein are systems and methods for
`encapsulating a stack of semiconductor dice. 1n the follow—
`ing description. numerous specific details are set
`forth.
`However, it is u nderstood that embodiments of the invention
`may be practiced without these specific details.
`In other
`instances, well-known circuits, structures and techniques
`have not been shown in detail in order not to obscure the
`understanding of this description.
`
`[0027] FIG. 2 shows a cross-sectional view of an inte-
`grated circuit device containing an encapsulated stack of
`dice 200, according to one embodiment of the present
`invention. The stack includes first die 270 that is mechani—
`cally and electrically attached to a first support 250, a second
`die 230 that is mechanically and electrically attached to a
`second support 210, connectors 240 such as reflowed solder
`balls that electrically connect the first and the second sup-
`ports, and an encapsulant material 280 formed around the
`stack of dice. The encapsulant covers and [ills at least a
`portion of the stack of dice and is useful for providing
`mechanical strength, protection, and a hermetic sea]
`to
`protect against environmental moistu re. As will be discussed
`in further detail below, the present inventors have discovered
`systems and methods for encapsulating the stack of dice
`substantially concurrently, during the same encapsulation
`operation. Embodiments of the present
`invention allow
`improved stacked die devices that may be fabricated by
`elIicient methods and that may have reduced thickness to
`extend their uses in small electronic devices.
`
`[0028] The stack of dice contains the first die and the
`second die. As used herein, the terms "die" and “dice“ {dice
`is the plural of die) will be used to refer to portions of
`semiconductor material, often thin rectangular portions,
`having a front side on which any desired electrical circuits
`have been fabricated, and having a backside which may be
`devoid of electrical circuitry and that may be attached to a
`support. The terms will refer to the portions prior to encap-
`sulation as well as in the encapsulated stack. The dice will
`
`commonly be obtained from one or more conventional
`semiconductor substrates or wafers that contain the desired
`electrical
`circuits
`formed
`therein
`by
`conventional
`approaches. Often it will be desirable to thin the semicon—
`ductor substrate to a thickness in the range of approximately
`75—150 micrometers (a micrometer or micron is a unit of
`one-millionth of a meter), or less,
`in order to provide a
`thinner package and to allow the dice to be somewhat
`flexible and able to flex to relieve stresses during subsequent
`processing operations including encapsulation. Well-known
`wafer thinning techniques such as plasma etching or chemi-
`cal—mechanical polishing may be used, although this is not
`required. After any desired thinning, which is optional. the
`wafer may be cut into the die portions, for example with a
`dicing saw.
`[0029] The stack aLso contains the first support and the
`second support. As used herein, the term “die support" and
`"support" will be used to refer to a signaling medium that is
`able to mechanically and electrically connect with a die and
`conduct signals received from the die to another support,
`signaling medium, or die. in general, the support contains a
`signal path, often a patterned conductive material, within a
`non-conducting or insulating material. The patterned con-
`ductive material may be a metal line, trace, wire, or inter-
`connect. Often,
`the pattemed conductive material will
`include a highly conductive metal, such as gold, platinum,
`copper. copper plated with solder. copper plated with a
`tinvlead alloy, aluminum, or alloys thereof in order
`to
`provide
`a highly conductive
`low—resistance
`signaling
`medium. Hereafter the term metal will be used to include
`metal alloys and multi-layer or plated metals. However, the
`use of highly conductive metals is not required and other
`conductive materials such as less conductive metals and
`refractory metal silicidcs may also be used. Many printed
`circuit boards that are commonly used in the art of semi-
`conductor die packaging are contemplated to be suitable
`supporLs. As a first example, a suitable support may contain
`a thin sheet of insulating polymeric material (e.g., a poly-
`imide, epoxy, epoxy composite, bis-maleimide-triazine,
`cyanale ester, or other insulating polymeric) having formed
`thereon a patterned conductor {e.g., a patterned metal). One
`particular support that is suitable is a polyimide sheet having
`formed thereon a patterned conductive material containing
`copper. Another particular support that is suitable is an [ill-4,
`or FR-S printed circuit board comprising one or more plies
`ofa woven-glass cloth reinforced with epoxy and containing
`patterned conductive material
`containing copper. Yet
`another support that
`is suitable is 3 flex tape. Of course,
`polymeric materials are not required. As a second example,
`a suitable support may contain a ceramic material containing
`a patterned conductive material.
`[0030] The support contains encapsulant flow openings
`220-225 and 260-265, which are inventive features discov-
`ered by the present inventors to allow a liquid encapsulant
`to flow from one side of a support
`to another side of a
`support in order to encapsulate the stack of dice. Typically,
`a liquid encapsulant is brought into contact with the stack of
`dice and is allowed to flow into, and through, the encapsu-
`lant flow openings. The inclusion of the flow openings may
`allow semiconductor die located at dilferent
`levels of the
`stack to be encapsulated, and voids between different levels
`of the stack filled with encapsulant, substantially concur-
`rently and in a single application of encapsulant material,
`rather than in separate, independent. and sequential appli-
`
`

`

`US 2004/0016939 A1
`
`Jan. 29, 2004
`
`LA
`
`cations of molding compou nds, as found in the prior art. The
`encapsulation process may be operated, and the flow open-
`ings designed, so that the encapsulant is able to flow through
`the flow openings of the support to encapsulate the stack of
`dice before sufficient solidification takes place to halt further
`flow.
`
`[0031] Different numbers, shapes, sizes, and positions of
`the openings 220-225 and 260-265 are suitable for different
`embodiments of the present invention. Regular shapes such
`as a rectangular slits, squares, triangles, or circles will often
`be desired, although irregular or arbitrary shapes may also
`be used. The openings are positioned su ificiently proximate
`the die to encourage the encapsulant to flow directly towards
`the die and cover the die without forming pockets or voids.
`For example,
`in the particular embodiment illustrated, the
`openings in the first support 260, 265 are positioned proxi-
`mate the first die 270, on opposite sides thereof, in order to
`facilitate encapsulant access to both sides of the die 270.
`However, if highly viscous encapsulants are avoided, if
`sufficient pressures are employed, or if the formation of
`voids during encapsulation is otherwise unlikely, the open-
`ings may be positioned more distant from the die, or on a
`single side of the die. In the particular device shown, the
`flow openings are positioned outside the solder ball connec-
`tors, which may allow a small device with the connectors
`located in close proximity to the die, although this is not
`required.
`
`[0032] The desired size and number of the openings may
`depend upon a number of factors. In general, larger sized
`encapsulant
`flow openings may be desired for larger [ill
`volumes (cg, stacked dice structures with larger void
`volumes to be filled with encapsulant), and for higher fill
`rates (e.g., tilting the same void volume in a shorter period
`of time). A smaller flow opening may often be used if a
`higher pressure driving force is used to deliver the viscous
`encapsulant. It will be appreciated that, at least to a point, a
`larger encapsulant flow opening may be nearly equivalently
`substituted for by one or more smaller encapsulant fiow
`openings. A particular amount of encapsulant flow in a
`particular period of time may be achieved by either a larger
`number of smaller openings or a smaller number of larger
`openings. The sizes of the openings may then depend upon
`the total opening area needed to fill the void volume of the
`stack of dice divided in rough proportion by the number of
`openings to conduct the flow of encapsulant to these void
`volumes.
`
`[0033] The size and number of the openings may also
`depend upon rheological properties of the encapsulant. Vis-
`cosity is a well-known Theological property that character-
`izes the resistance of a material to flow. To illustrate, a
`viscous liquid like honey has a higher viscosity than water
`and correspondingly flows more slowly than water. Just as
`it may be dillicult to induce honey to How quickly through
`a narrow opening, it may similarly be more diflicult to flow
`a viscous liquid through a particular opening than would be
`the case for a less viscous liquid. Accordingly, a larger
`encapsulant flow opening may be desired for a more viscous
`encapsulant. For some encapsulants, such as those whose
`viscosity quickly increases during the flowing process, it
`may be desirable to use a larger flow opening sttfiicient to
`achieve a certain amount of flow during a period of time
`before the encapsulant becomes so viscous that its resistance
`to flow overcomes the available pressure driving force and
`
`further flow stops prematurely before the voids of the stack
`of dice are filled. The viscosity of the encapsulant may
`increase for a number of reasons, including due to molecular
`weight
`increasing reactions, or due to cooling (viscosity
`generally increases with decreasing temperature).
`[0034] The encapsulant is formed contiguously, in a con-
`tinuous and unbroken connection,
`in the different void
`regions ofthe stack of dice by flowing to the regions through
`the plurality of encapsulant flow openings 220, 225 and 260.
`265 of the respective supports 210 and 250, and solidifying
`in these regions. As shown. the encapsulant has solidified the
`surfaces of the dice, the surfaces of the support on opposite
`sides of the dice, between the dice, between the supports,
`around the connectors and within the flow openings. Once
`solidified,
`the
`encapsulant provides
`a protective
`and
`mechanically integral packaging for the dice. It is contem-
`plated that the contiguous, seamless, and integral encapsu-
`lation of the stack of dice may provide improved strength
`and reduced blistering, peeling, and other separations due to
`thermal and mechanical stresses.
`
`[0035] A variety of encapsulants are suitable for use with
`the present
`invention.
`in general, a suitable encapsulant
`should provide sufiicienl mechanical strength to hold the
`stack of die together during subsequent processing and use,
`should be a sufficiently non-conductive material
`to avoid
`unintended electrical connections between proximate eon-
`ductive materials, should be compatible with the other
`materials used in the integrated circuit device, and should
`have rheological properties that allow it to flow through the
`encapsulant flow openings and stack of dice without forming
`voids that would impede proper operation of the device.
`Many conventional molding compounds, epoxy molding
`compounds, filled epoxy molding compounds, and other
`materials commonly used for packaging semiconductor die
`are suitable, and commercially available from a number of
`SOURCES.
`
`[0036] According to one embodiment ofthe present inven-
`tion, the encapsulant contains a fast curing polymer material,
`such as a phenol-formaldehyde Novolac-type epoxy resin.
`containing one or more filters or other additives to modify
`the encapsulants theological, thereto—mechanical, dielectric,
`or other properties. This particular encapsulant may be
`prepared by combining appropriate conventional propor-
`tions of an epoxide, such as epichlorohydrin, with one or
`more curing materials, such as phenol and formaldehyde,
`and with varying desired amounts of filler, such as silica.
`Such filled epoxies are commonly used in the semiconductor
`processing arts and their properties are well known.
`[0037] The filler may be added in varying proportion in
`order to modify, for example,
`the coefficient of thermal
`expansion of the encapsulant so that it is sufficiently similar
`to that of the semiconductor die so that the encapsulant and
`the die thermally expand and contract together to avoid
`potentially damaging mechanical stresses due to changes in
`temperature. This may help to maintain contact and integrity
`between the die and the encapsulant. In one instance, the
`silica may be added as particles having an average diameter
`of around 10 micrometers and in an amount that is around
`75-90 wt 9'6. This particular filter may also be replaced by
`other such as line or powdered sand, quartz, silicon dioxide,
`clay, or the like.
`[0038] Such a resin and liller may have a viscosity that is
`in the range of approximately 50-200 poise before signifi-
`
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`

`US 2004/0016939 A1
`
`Jan. 29, 2004
`
`cant curing, at an encapsulation temperature of that is in the
`range of approximately 170180" C. The encapsulant vis-
`cosity may be measured, for example by determining the
`flow of the encapsulant
`in a circular tube of a capillary
`viscometer, or by another desired technique. The resin may
`cure by way of molecular weight increasing reactions that
`increase the viscosity of the encapsulant, restrict its ability
`to flow, and eventually lead to solidification of the encap-
`sulant. The reactions may proceed with a gel time that is
`often less than a minute at
`temperatures. between about
`”(t-180° C.
`
`[0039] FIG. 3 shows a top view of a die support 300 that
`includes a rigid frame 310 and a flexible support sheet 350,
`according to one embodiment of the present invention. The
`support sheet may be attached to the frame in order to
`facilitate handling of the flexible support sheet and then the
`die may be attached to the framed support sheet.
`
`[0040] The frame 310 may contain a number of rigid
`materials. Suitable materials include metals (cg, copper,
`aluminum, stainless steel, chrome, titanium, etc.}, ceramics,
`graphite, plastics (e.g., polyethylene, styrene,
`fiberglass,
`composites, etc.}, and other materials. The frame contains a
`window opening 320 to expose a portion of the flexible
`support sheet 350 containing a die position 360 and encap-
`sulant flow slits 370A-D when the support sheet is properly
`attached to the frame. The frame contains optional alignment
`holes 330A-D located in its corners. The holes may be
`drilled, cut, punched, or otherwise formed. Jigs such as
`guide pins or rods may be inserted into the alignment holes
`330A-I) and into the alignment holes of another frame in
`order to align the frames relative to one another and establish
`and mechanically maintain a desired relationship between
`the frames and dice positioned and supported thereon. In one
`instance the alignment holes may allow aligning one frame
`to another with a tolerance of about 30 micrometers, or
`better, although this is not required. Alternatively, the die
`may be aligned manually, such as by using the outer
`perimeter of the frame as a guide. Even if the alignment
`holes are desired, it is not necessary to include all four holes.
`The frame additionally contains alignment teeth 340A—D to
`align the support sheet relative to the frame. The alignment
`teeth may be similar to the sprocket
`teeth to couple with
`perforations in the film in a camera to advance the film,
`although there is no requirement
`that
`the teeth be on a
`cylindrical surface. Four teeth are shown in the particular
`embodiment, although less teeth or more teeth 340E may
`also be used.
`
`[0041] The flexible support sheet 350 may contain a
`flexible version of a support as previously described. For
`example, the flexible support sheet may comprise a flexible
`insulating material
`containing a
`conductive
`signaling
`medium. Suitable flexible support sheets include polymeric
`sheets containing patterned conductive material, flexible
`printed circuit boards, flexible FR-4 sheets, flexible FR-S
`sheets, flex tape, and the like. The flexible support sheet may
`desirably be thin, to facilitate fabrication of a thin, low-cost
`device. 'lhe sheet contains alignment openings or perfora-
`tions 380A—D and optionally 380E that respectively corre—
`spond to the alignment
`teeth 340A-D and 34013. In one
`instance the teeth and openings allow a sheet to be aligned
`relative to a frame with a tolerance ofabout 30 micrometers,
`or better. although this is not required.
`
`[0042] The sheet also contains four encapsulant flow slits
`370A-D positioned in proximate the die attach position 360,
`along all four sides thereof, to allow encapsulant flow to the
`die position. The present
`inventors have found that elon—
`gated rectangular slits, such as those shown, may provide
`good distribution of encapsulant around the die position and
`may additionally relieve stresses in the sheet and in an
`attached die. although it is to be appreciated that the slits are
`not required and may be replaced by squares, circles or other
`openings. The slits may have a length that is a significant
`portion of the semiconductor die to be attached and may
`have a width that is sufficient to allow a particular encap~
`sulant to flow through all available openings to fill the voids
`ofa stack of dice within an acceptable period oftime. It will
`be appreciated that, at least to an extent, an increase in width
`may allow a decrease in length, and visa versa.
`In one
`particular embodiment, a die has length and width of about
`13 millimeters, and the slits 370A-D have a length that is in
`the range of approximately 50»IOU% the length of the die,
`and a width that is in the range of approximately 0.5-2.0
`millimeters or approximately 0.75—1.25 millimeters for an
`encapsulant such as the filled epoxy resin discussed above
`that has a viscosity that is in the range of approximately
`50-201] poise. Of course smaller widths may be used for less
`viscous encapsulants and larger sized slits may be used for
`more viscous encapsulants. The appropriate sizes for the
`openings may be determined empirically through tests on
`different sized openings, or maybe determined by fluid flow
`modeling or simulation. In the particular embodiment illus-
`trated, a slit is provided along each of the four sides of the
`die position, although this is not required.
`
`[0043] The slit and teeth perforation openings in the
`support sheet may be formed by a variety of approaches. In
`the case ofa thin flexible support sheet. it may be convenient
`to form the openings and slits by puncturing or pressurized
`cutting of the sheet with a shearing action that
`tears the
`sheet. This may resemble the shearing action employed by
`a conventional hole puncher used for ordinary paper sheets.
`For example, the sliLs may be punched or punctured. Alter-
`natively, the openings could be cut, drilled, or formed by
`other known approaches.
`
`[0044] FIG. 4 shows a top view of a die 490 attached to
`the assembled die support 300 of FIG. 3, according to one
`embodiment of the present
`invention. The support
`is
`assembled by inserting the jig teeth 440A-D of the frame
`into the openings 480A-D of the flexible support sheet to
`align the support sheet with the frame. An adhesive may be
`used to further attach the sheet to the frame. This places the
`die position 460 and the slits 470A—D within the window 420
`of the frame. The die 490 may then be attached to the die
`position 460.
`
`in a manufacturing
`It will be appreciated that
`[004-5]
`environment it may be desirable to concurrently encapsulate
`a number of stacked die structures in a single molding
`operation. FIG. 5 shows such a suitable support 500, accord-
`ing to one embodiment of the present invent ion. The support
`contains a frame 510 and a flexible support sheet 520. The
`frame and support sheet contain features that may be similar
`to those shown in FIG. 4, including alignment holes 512A-
`I), teeth 514, Windows 516A-B, openings for teeth 522,
`encapsulant flow slits 524, and die positions 526. Two slits
`and die positions are identified, although it is to be appre-
`ciated that 48 slits and 18 die positions are shown. As
`
`

`

`US 2004/0016939 A1
`
`Jan. 29, 2004
`
`the support may
`indicated by identifiers 518 and 528,
`contain any desired additional teeth, windows, teeth open-
`ings, slits, and (lie positions.
`
`[0046] FIG. 5 also shows dice 532 on an assembled die
`support 530, according to one embodiment of the present
`invention.
`In the particular illustration, 18 dice 532 are
`attached to the support sheet at the corresponding 18 die
`attachment positions 526. The assembled die support may be
`stacked on other analogous supports, with or without align-
`ment using the alignment openings 512A—D, so that the 18
`dice are stacked relative to a corresponding set of [8 dice on
`another supports. The multiple stack of dice may be placed
`in an encapsulation chamber, concurrently encapsulated, and
`cut and formed into 18 integrated circuit devices containing
`encapsulated stacks of dice.
`
`[004-7] According to an alternate embodiment of the
`present invention, the support may comprise a su