JP2010114111A - Recoverable electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recoverable electronic component that can have a prescribed component recovered without any damage even if an electronic device or circuit board is defective. <P>SOLUTION: The electronic component includes a base insulating layer 10 having a first surface and a second surface, an electronic device 18 which has a first surface and a second surface and is fixed to the base insulating layer 10, an adhesive layer 16 which is disposed between a first surface of the electronic device 18 and a second surface of the base insulating layer 10, and a removable layer 26 which is disposed between the first surface of the electronic device 18 and the second surface of the base insulating layer 10. The base insulating layer 10 is fixed to the electronic device 18 with the removable layer 26 interposed. The removable layer 26 enables the base layer 10 to be peeled from the electronic device 18. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The invention includes embodiments that relate to the manufacture of a wiring structure. The invention includes embodiments that relate to a method of recovering a chip or other electrical component from a wiring structure.

  Bonding electronic devices such as semiconductor chips, discrete passive elements, BGA carriers and other electrical elements to printed circuit boards, substrates, wiring structures or flex circuits is generally performed by solder or adhesive. In the area array solder mounting structure, the temperature is raised to reflow the solder, and after cooling, it hardens to form an electrical connection. In applications where the coefficient of thermal expansion (CTE) of the electronic device and the CTE of the substrate on which the electronic device is mounted do not have very close values, thermal cycling can stress the solder joints and cause fatigue failure of the solder There is a case. One way to overcome this problem is to wrap the solder joint with a polymer resin underfill, such as a filled epoxy, to relieve the stress at the solder joint. Underfill can be applied by supplying a liquid resin to one or both sides of the part and allowing the resin to flow under the part by capillary action.

  Electronic devices that are sensitive to exposure to temperatures as high as 200 ° C. should not use high temperature thermoplastic bonding materials. Furthermore, the low temperature thermoplastic material cannot be subjected to subsequent processing steps such as curing, or certain assembly steps that exceed the melting or softening temperature of the thermoplastic material. Therefore, when processing such an electronic device, a thermosetting adhesive that is cured at a relatively low temperature (less than 200 ° C.) but is stable even at a high temperature during a subsequent processing step or in a use environment is used. . Further, low temperature bonding and low temperature bonding are preferred because a zero stress point is established at the bonding temperature and the low bonding temperature reduces the stress of the wiring structure at normal operating temperatures.

  If multiple electronic devices are mounted on a common substrate and one of the devices is found to be defective after solder mounting and underfill curing, the defective device can be removed and replaced with a new component It is generally desirable to rescue other electronic devices disposed on the substrate. A problem with the use of a thermoplastic underfill resin is that it does not remelt at normal processing temperatures. Therefore, it is impossible to remove a defective electronic device, and the entire circuit must be discarded. Therefore, if a thermoplastic adhesive having a low processing temperature and low stress is used, the processing process cannot be repaired. In addition, remeltable and repairable thermoplastics require high temperature processing, resulting in high stress structures that are not suitable for many planned applications.

  Furthermore, a similar problem occurs when the wiring structure is applied to an embedded chip that is directly mounted on the surface of an electronic component. In those applications, when a thermoplastic adhesive is used to join an electronic component to a wiring structure, the melting temperature of the thermoplastic material is high, resulting in excessive stress on the structure, or the melting temperature of the thermoplastic material. The component operation and / or assembly temperature is severely limited due to the low Furthermore, the thermoplastic adhesive turns into a liquid while joining the chip to the membrane, and as a result, the chip may move during processing. When thermosetting adhesives are used in these applications, the stress is reduced and the range of operating and assembly temperatures is increased, but recovery of electronic components is not impossible, but becomes extremely difficult.

In current embedded chip processing, referred to as embedded chip build-up (ECBU) or chips-first build-up (CFBU) technology, a bare chip is mounted with a peripheral I / O pad or a peripheral I / O pad, or an I / O on the top surface. The O-pad array is mounted in a distributed state to form a high density wiring structure without the need for solder joints or wire bonds. ECBU processing or CFBU processing can be used to form chip carriers that connect complex semiconductor chips to large contact pads that are compatible with circuit board level structures such as printed circuit boards. While these high performance chips can be worth hundreds of dollars, the carriers formed to interface the chips to the circuit board can be an order of magnitude cheaper. Since all complicated wiring structures have processing defects such as short circuits and / or open circuits, a decrease in yield is inevitable. In a conventional flip chip or wire bonded chip carrier structure, the wiring structure is manufactured as a finished product and electrically tested before assembling expensive chips. Therefore, defects in the wiring structure do not cause loss of expensive chips. In the ECBU process, the chip is bonded to the wiring structure before manufacturing the wiring structure, so that a chip without a defect may be discarded together with a defective package.
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  In one embodiment, the present invention provides an electronic component. The electronic component includes a base insulating layer having a first surface and a second surface, an electronic device having the first surface and the second surface, and being fixed to the base insulating layer, and a first of the electronic device. An adhesive layer disposed between the surface and the second surface of the base insulating layer, and a removable layer disposed between the first surface of the electronic device and the second surface of the base insulating layer. Including. The base insulating layer is fixed to the electronic device through the removable layer.

  The removable layer can peel the base insulating layer from the electronic device. Removal can be performed without damaging certain parts of the electronic component.

  The invention includes embodiments that relate to the manufacture of electronic devices or wiring structures. The invention includes embodiments that relate to a method of recovering a chip or other electrical component from a device. The method may recover an undamaged electronic device such as a chip from a defective wiring structure or package. The method may be useful in processes related to resin underfill or other embedded chip technology. However, the method may be used in applications where recovery of electronic devices from a wiring structure or package is desired.

  In one embodiment, the method may provide a wiring structure or an electronic component. The method includes applying a removable layer to the electronic device or base insulating layer, applying an adhesive layer to the electronic device or base insulating layer, and using the adhesive layer to attach the electronic device to the base insulating layer. Fixing.

  The electronic component can include a base insulating layer having a first surface and a second surface, and an electronic device having a first surface and a second surface. The electronic device is fixed to the base insulating layer. Among the volumes defined between the opposing surfaces of the electronic device and the base insulating layer are an adhesive layer and a removable layer. In particular, the adhesive layer may be disposed between the first surface of the electronic device and the second surface of the base insulating layer, and the removable layer may be disposed between the first surface of the electronic device and the base insulating layer. You may arrange | position between 2nd surfaces.

  Suitable materials for use as the base insulating layer may include one or more of polyimide, polyetherimide, benzocyclobutene (BCB), liquid crystal polymer, bismaleimide-triazine resin (BT) resin, epoxy or silicone. . Commercially available materials suitable for use as the base insulating layer are KAPTON H polyimide or KAPTON E polyimide (manufactured by EI du Pont de Nemours), APICAL AV polyimide (manufactured by Kaneka Chemical Co., Ltd.), UPILEX polyimide (Manufactured by Ube Industries, Ltd.) and ULTEM polyetherimide (manufactured by General Electric) may be included. In the illustrated embodiment, the base insulating layer is fully cured as KAPTON H polyimide.

  The base insulating layer may form a wiring structure, a flex circuit, a circuit board, or other structures. The wiring structure can implement one or more electronic devices and can be interconnected with those electronic devices. For one embodiment, selective characteristics for the base insulating layer include elastic modulus, thermal expansion coefficient, and hygroscopic expansion coefficient that minimize dimensional changes during processing. In order to maintain flexibility, the thickness of the base insulating layer may be minimized. The base insulating layer optionally supports the metallization layer on both the first side and the second side and is rigid enough (thickness, support to maintain dimensional stability throughout subsequent processing steps). (Either by structure or material properties).

  With respect to the thickness of the base insulating layer, an appropriate thickness may be selected in relation to the end use, number and type of electronic devices, and the like. The thickness may exceed about 10 μm. The thickness may be less than about 50 μm. In one embodiment, the base insulating layer has a thickness in the range of about 10 μm to about 20 μm, about 20 μm to about 30 μm, about 30 μm to about 40 μm, or about 40 μm to about 50 μm, or greater than about 50 μm. For one embodiment where the base insulating layer is a circuit board, the appropriate thickness of the base insulating layer may be based on the number of layers in the circuit board. In general, the number of circuit board layers ranges from about 20 to about 50 or more, and each layer has a thickness of about 100 μm.

  The adhesive layer is a thermosetting adhesive. Examples of suitable adhesives may include a thermosetting polymer. Suitable thermosetting polymers may include epoxies, silicones, acrylic resins, urethanes, polyetherimides or polyimides. Suitable commercially available thermosetting adhesives are CIBA GEIGY 412 (manufactured by Ciba Geigy), AMOCO AI-10 (manufactured by Amoco Chemicals Corporation) and PYRE-MI ™ (manufactured by EI du Pont de Nemours). ) Or the like. CIBA GEIGY 412 has a glass transition temperature of about 360 ° C. Other suitable adhesives may include thermoplastic adhesives, water curable adhesives, room temperature curable adhesives, and radiation curable adhesives.

  In one embodiment, the low temperature sensitive adhesive layer secures or bonds the electronic device to the base insulating layer. In this case, the low temperature sensitive adhesive layer may serve as both an adhesive layer and a removable layer. The adhesive loses its adhesive strength at the defined low peel temperature.

  A suitable low temperature sensitive adhesive may be a thermosetting adhesive. Examples of suitable low temperature sensitive adhesives include epoxy or polyimide. A number of commercially available adhesive properties are available, and adhesive materials can be cured, cured at low temperatures (if applicable), outgassing, thermal and oxidative stability, and bonded in the temperature range of interest. You may select based on factors, such as intensity. The selection of the low temperature sensitive adhesive may include matching the coefficient of thermal expansion of the low temperature sensitive adhesive to one or more components of the wiring device. In one embodiment, the low temperature sensitive adhesive may have a coefficient of thermal expansion (CTE) in the range of about 15 ppm / ° C. to about 20 ppm / ° C. Low temperature sensitive adhesives must lose adhesion at temperatures below the operating temperature of the wiring device. Furthermore, there is a need to select a low temperature sensitive adhesive that does not chemically interact with the electronic device.

  An adhesive layer may be applied to form a layer having a thickness greater than about 5 μm on the surface of the base insulating layer. In one embodiment, the adhesive layer has a thickness in the range of about 5 μm to about 10 μm, about 10 μm to about 20 μm, about 20 μm to about 30 μm, about 30 μm to about 40 μm, or about 40 μm to about 50 μm, or greater than about 50 μm. Has a thickness.

  The adhesive layer may be applied to the base insulating layer by spin coating, spray coating, roller coating, meniscus coating, screen printing, stencil, pattern print deposition, jetting or other application methods. In one embodiment, the adhesive is applied by dry film lamination. The adhesive layer may be applied so as to cover a part or the whole of the second surface of the base insulating layer. For example, an adhesive layer may be applied to selected areas on the base insulating surface, such as an electronic device mounting location, and other areas on the surface of the base insulating layer, such as electrical contact pads or electrical test pads, are not covered. It may be left as it is. This may be performed by a direct application method such as jetting, or a standard stencil or screen printing structure process used to selectively apply a solder mask resin onto a circuit board, substrate or component. You may perform by a process. The direct coating process may deposit a layer having a thickness of less than about 50 μm, and the screen printing technique may form a deposited layer having a thickness of greater than about 50 μm.

  In one embodiment, the adhesive layer may be applied to the electronic device in liquid form and dried. The adhesive layer itself may be applied in liquid form or may be deposited as part of a liquid solution mixed with a solvent, for example. In one example, a suitable liquid thermosetting polymer is 24.8 wt% CIBA GEIGY 412, FC 430 ™ (3M interface in a liquid solution containing 66.4 wt% N-mp. Active agent) 0.1 wt% solution and 8.3 wt% DMAC. The droplets of material may be delivered onto the electronic device in a volume sufficient to form a coating film of about 200 μm to about 1,000 μm. After the adhesive solution is applied, the material may be dried through a series of thermal steps such as about 150 ° C. for 10-20 minutes, about 220 ° C. for 10-20 minutes, and about 300 ° C. for 10-20 minutes. . The number and duration of the thermal process and the temperature used will depend on the particular thermoset polymer or other material utilized. This drying sequence removes the solvent from the thermosetting adhesive solution and leaves a completely dry layer of adhesive on the electronic device. Thermoset polymers are fully crosslinked, do not dissolve in solvent solutions, and do not soften unless exposed to very high temperatures.

  If necessary, the adhesive layer may be fully cured to bond or secure the electronic device to the base insulating layer. It is necessary to use a curing temperature lower than the melting temperature of the removable layer.

  In one embodiment, the removable layer comprises a thermoplastic polymer. Suitable thermoplastic polymers for use in forming the removable layer include thermoplastic resins including polyolefins, polyimides, polyetherimides, polyetheretherketones, polyethersulfones, silicones, siloxanes, or epoxies, but these It is not limited to. Examples of suitable thermoplastic polymers are XU 412 (commercially available from Ciba Geigy), ULTEM 1000 and ULTEM 6000, polyetherimide resins manufactured by GE Plastics, VITREX, a polyetheretherketone commercially available from Victrex. XU 218, a polyethersulfone commercially available from Ciba Geigy, and UDEL 1700 ™, a polyethersulfone commercially available from Union Carbide.

  Suitable methods for applying the removable layer to electronic devices include spray coating, spin coating, roll coating, meniscus coating, dip coating, transfer coating, jetting, drop dispensing, pattern print deposition or dry film lamination. . The removable layer may have a thickness greater than about 5 μm. In one embodiment, the removable layer has a thickness in the range of about 5 μm to about 10 μm, about 10 μm to about 20 μm, about 20 μm to about 30 μm, about 30 μm to about 40 μm, or about 40 μm to about 50 μm, or greater than about 50 μm. Has a thickness.

  The removable layer may be applied to the electronic device while the electronic device is in the form of a single part or at a time when the electronic device is in the form of a panel or wafer. For example, if the electronic device is a semiconductor chip, the removable layer may be applied at the wafer level or after wafer processing is complete and wafer sawing is performed. The wafer is cut into two or more individual chips using semiconductor wafer dicing equipment. The chip may be washed with water in order to remove fragments by sawing. Alternatively, after wafer sawing, the removable layer may be applied directly to individually separated chips. If the removable layer is applied at the wafer level, the removable layer may be attached to one chip by spin coating or spray coating. When the removable layer is applied to individually separated chips, the removable layer may be applied by spray coating or drop dispensing. For small packaged electronic devices such as area array chip scale components, the electronic device may be manufactured as a panel in which multiple devices are processed together, so that the removable layer can be roll coated, meniscus coated or another batch You may apply | coat by the apply | coating method.

  The removable layer may be applied to cover part or all of the first surface of the electronic device. For example, the removable layer material may be applied to selected areas of the electronic device, such as a device mounting location, in which case I / O contacts or other desired areas on the electronic device remain uncovered. . This may be accomplished by a direct application system such as jetting, or by a standard stencil or screen-printed structure processing step used to selectively apply a solder mask resin to a circuit board, substrate or component. May be achieved.

  If the removable layer partially covers the first side of the electronic device, the adhesive layer must also partially cover the second side of the base insulating layer. In particular, when the electronic device is disposed on and bonded to the base insulating layer, the region on the first surface of the electronic device that is not covered by the removable layer is not in contact with the adhesive on the base insulating layer. The adhesive layer needs to be applied to selected areas of the electronic device mounting location.

  The removable layer may be made from a soluble polymer or a solvent swellable polymer. Accordingly, a solvent or solvent mixture may be applied to the wiring structure to dissolve, soften or swell the removable layer. Thereby, the electronic device is peeled from the base insulating layer and the wiring structure. In this electronic device recovery method, the wiring structure and the mounted device may be immersed in a solvent bath. The solvent in the bath dissolves, softens or swells at least a portion of the removable layer. This solvation can remove the wiring structure from the first surface of the electronic device. Cold sensing electronic devices and other components are not exposed to undesirably high temperatures such as those used in heat recovery processes. The soluble polymer or solvent swellable polymer may be a thermoplastic polymer.

  Suitable solvents include solvents that can dissolve, soften or swell the removable layer. A particular solvent may be selected in relation to the material composition of the removable layer. Depending on the material of the removable layer, suitable solvents are one or more of acetone, anisole, acetophenone, benzene, toluene, alcohol, g-butylatone, N-methylpyrrolidone, methylene chloride, dimethyl sulfoxide (DMSO), and the like. May be included. Other suitable solvents include acids and bases for pH sensitive removable layer materials such as sulfuric acid.

  In one example, a first solvent mixture of 4 parts by weight of metacresol and 16 parts by weight of orthodichlorobenzene (ODCB) and a second solvent mixture of 4 parts by weight of metacresol and 16 parts by weight of acetophenone, The solvent soluble removable layer made from ULTEM 6000 is dissolved. You may change these material ratios as needed. In addition, solvent soluble polymers including PEEK ™ may be dissolved in concentrated sulfuric acid, and solvent soluble polymers including XU 218 thermoplastic materials are g-butylactone, N-methylpyrrolidone, methylene chloride, acetone. And may be dissolved in a solvent such as acetophenone.

  When recovering a functioning electronic device from a defective wiring structure, it is necessary to use a solvent that does not chemically react with the electronic device or a solvent that does not damage the electronic device. On the other hand, when it is desired to remove a defective electronic device from a functioning wiring structure, a solvent that does not chemically react with wiring structure components (excluding electronic devices and removable layers) or their components It is necessary to use a solvent that does not damage the surface. Furthermore, a wet etchant may be used in combination with heat to dissolve the removable layer and recover the electronic device.

  Low temperature sensitive adhesives tend to lose adhesion or mechanical strength at a sufficiently low threshold temperature. In one embodiment, the removable layer may be exposed to low temperatures that cause the adhesive material to lose adhesion and thereby cause the electronic device to peel. In another embodiment, the removable layer may be exposed to low temperatures that cause the adhesive material to become brittle and break, thereby peeling the electronic device. The holding device may fix the electronic device and hold it against the wiring structure. The wiring structure containing the low temperature sensitive adhesive may be cooled to a temperature of about −75 ° C. or less. The temperature is selected based on the properties of the removable layer.

  When the functioning electronic device is separated from the defective base insulating layer and recovered from the wiring structure, the wiring structure needs to be cooled to a temperature above the minimum damage threshold temperature of the electronic device. The minimum damage threshold temperature of an electronic device is the lowest temperature at which the device can be exposed without damaging the active components of the electronic device. On the other hand, when it is desired to remove a defective electronic device from the functioning base insulating layer and to recover the electronic device from the wiring structure, the wiring structure is lower than the minimum damage threshold temperature of the functioning base insulating layer. It needs to be cooled to a high temperature. The minimum damage threshold temperature of the functional base insulation layer is the lowest temperature at which the functional base insulation layer can be exposed without damaging the part.

  After the electronic device is removed from the wiring structure, the residual adhesive layer and the conductive material disposed in the via may remain on the electronic device. Residual conductive material or excess residual adhesive layer on the surface of the electronic device and in the via may be removed by wet etching, plasma etching, chemical etching or reactive ion etching, It may be removed by plasma etching, chemical etching or reactive ion etching. Further, when the conductive material is made of metal, the portion of the conductive material remaining on the electronic device may be removed by metal etching. If the conductive material includes a Cu or Ti: Cu bimetal structure, Cu may be etched with nitric acid to leave a thin Ti metallization in place.

  After the remaining adhesive layer and conductive material are removed from the electronic device, the device is almost in its original state and can be assembled to another wiring structure.

  In one embodiment of forming the removable layer, the thermoplastic polymer is applied to the electronic device in liquid form and then dried. The thermoplastic polymer may be applied in liquid form, or may be deposited as part of a solution mixed with a solvent, for example. In one example, CIBY GEIGI XU 412 which is a 4.1 wt% solution of 2.5 wt% DMAC (dimethylacetamide), 27.3 wt% anisole and 66.1 wt% g-butyrolactone ( GBL) is mixed to form a suitable solution. The droplets of this material may be delivered onto the electronic device in a volume sufficient to form a coating film having a thickness in the range of about 100 μm to about 1,000 μm. After the liquid thermoplastic polymer has been applied, the material may be dried through a series of thermal steps. An example of a suitable thermal process may be about 150 ° C. for 10-20 minutes, about 220 ° C. for 10-20 minutes, and about 300 ° C. for 10-20 minutes. The number and duration of the thermal process, and the temperature used will depend on the particular thermoplastic polymer utilized. This drying sequence removes the solvent from the thermoplastic polymer solution and leaves a completely dry layer of thermoplastic polymer on the electronic device. As a result, a removable layer is formed.

  Another factor to consider is the pressure applied to the part during curing. Of course, the higher the pressure, the thinner the bond line. Spacer material may be added to the adhesive to adjust the bond line thickness if a pressure higher than that which allows a sufficiently thick bond line is required. The spacer material may be selected to have higher functionality as long as it has the desired thermal conductivity and electrical resistance as intrinsic properties.

  If the removable layer is a curable material, the removable layer may be cured after the removable layer is formed. The removable layer may be thermoset by radiation or a combination of heat and radiation. Suitable radiation may include ultraviolet (UV) light, electron beams and / or microwaves. The cured removable layer must be sufficiently transparent at visible wavelengths so that the automated vision system can distinguish between wafer saw lanes and I / O contact geometry during wafer sawing and chip pick and place processes. Such a transparent layer makes it possible to align the saw during wafer sawing as well as to align chips and other electronic devices during positioning. Furthermore, the cured removable layer must be capable of laser drilling at the wavelength used to perform ablation of vias through the base insulating layer. For example, the removable layer after curing is desirably laser drillable.

  After application of the adhesive layer, the adhesive layer may be cured. The adhesive layer is partially cured until the adhesive reaches the B stage point. In the B stage, the adhesive layer is not fully cured but is sufficiently stable to allow subsequent processing to be performed. The adhesive layer may be cured by heat or a combination of heat and radiation. Suitable radiation may include UV light and / or microwaves. If volatile materials are present during curing, a partial vacuum may be used to facilitate removal of the volatile materials from the adhesive.

  Referring to FIG. 1A, in one embodiment of the present invention, the base insulating layer 10 has a first surface 12 and a second surface 14. In order to stabilize the dimensions of the insulating base layer during processing, the insulating base layer is fixed to a frame structure (not shown in FIG. 1). The base insulating layer is formed from an electrically insulating material. Furthermore, the base insulating layer may be a polymer film capable of fixing a conductive material.

  As shown in FIG. 1B, an adhesive layer 16 may be applied to the second surface of the base insulating layer. The adhesive layer can be bonded to the electronic device 18 (see FIG. 1C). Thus, the adhesive layer can fix or bond the electronic device to the base insulating layer.

  As shown in FIG. 1C, the electronic device has a first surface 20 and a second surface 22. The first surface of the electronic device may be the active surface of the device on which one or more I / O contacts 24 are disposed. Examples of I / O contacts that may be placed on electronic devices include pads, pins, bumps, and solder balls. In the illustrated embodiment, the I / O contact is an I / O pad. Other suitable electronic devices are mounted or non-mounted semiconductor chips such as microprocessors, microcontrollers, video processors or ASICs (application specific integrated circuits), discrete passive elements or ball grid array (BGA) carriers. Also good. In one embodiment, the electronic device is a semiconductor silicon chip having an array of I / O contact pads disposed on a first surface.

  Still referring to FIG. 1 (c), a removable layer 26 is applied to the first surface of the electronic device. Thereafter, the partial structure of the electronic device and the removable layer may be assembled to the base insulating layer.

  In one embodiment, the active surface or first surface of the electronic device is disposed on the second surface of the base insulating layer such that the active surface of the electronic device having the removable layer is disposed in contact with the adhesive layer. (See FIG. 1D). For example, in this case, the base insulating layer may be placed on the heating stage of an automatic pick and place system that picks up each electronic device that is a chip from a diced wafer or from a tray of individually separated chips such as waffle packs. Good. The partially cured adhesive layer is heated so that the adhesive softens and becomes viscous but is not cured. Thereafter, the chip is formed on the first surface such that the active surface of the chip faces the second surface of the base insulating layer, whereby the I / O contact of each chip is aligned with a standard point on the base insulating layer. (See FIG. 1D).

  In one embodiment shown in FIG. 2 (a), the removable layer is applied to the first surface of the electronic device. The removable layer may be applied to the electronic device and is cured as described above in the first embodiment. The adhesive layer may be applied to the first surface of the electronic device on the removable layer and is used to join the electronic device to the base insulating layer as shown in FIG. Appropriate application methods are the same as described above.

  Referring to FIG. 2C, the active surface or the first surface of the electronic device having the removable layer and the adhesive layer may be disposed so as to be in contact with the second surface of the base insulating layer. In order to stabilize the dimensions of the insulating base layer during processing, the insulating base layer is fixed to the frame structure. In an automation system, a base insulating layer is placed on the heating stage of an automatic pick and place system that takes each electronic device, in this case a chip, from a diced wafer or from a tray of individually separated chips such as waffle packs. May be. The chip is then heated so that the partially cured adhesive softens and becomes viscous but not cured. Next, the chips are positioned such that the first surface of the electronic device is in contact with the second surface of the base insulating layer, so that the I / O contacts of each chip are aligned with the standard points on the base insulating layer. Is done. The adhesive layer may be fully cured as described above.

  Referring to FIG. 3 (a), in one embodiment, the base insulating layer is secured to a frame structure (not shown) to stabilize the dimensions of the base insulating layer during processing. In the present embodiment, as shown in FIG. 3B, the removable layer is not applied to the electronic device but applied to the second surface of the base insulating layer. The removable layer may be applied by the method described above.

  When the removable layer is removed from selected areas of the base insulating layer, the patterned removable is used so that the removable layer is used to define the metal areas protected from solder during solder mounting reflow The layer may be used as a solder mask material. When the patterned removable layer is used as a solder mask, the removable layer is used in a solder mask defining manner. In this manner, the solder mask material covers the edges of the solder contact pads and defines the areas where the solder will form bonds. Alternatively, the patterned removable layer may be used in a non-solder mask defining manner. In the non-solder mask defining method, generally, the solder mask does not overlap the edge of the solder contact pad, and the metal pad defines the solder area. Non-solder mask definition schemes leave a small area around each solder pad, where the underfill adhesive can form a permanent bond that prevents subsequent removal of the electronic device. Less preferred than the prescribed method. Solder masks are used to cover traces leading from solder pads or other adjacent metal shapes.

  Solder adhesion in the case of eutectic tin: lead solder is exposed to heat of about 220 ° C, and in the case of tin: lead solder with a high lead content, it is exposed to heat of about 300 ° C and does not contain lead Is exposed to a temperature of about 240 ° C to about 260 ° C. The material of the removable layer in this embodiment needs to be selected such that its melting point exceeds the solder reflow temperature of the selected solder system. The removable layer is the same as the removable layer described above.

  The adhesive layer is applied to the first surface of the electronic device and used to join the electronic device to the base insulating layer (see FIG. 3 (c)). The adhesive layer is applied to the electronic device as described above. However, in this embodiment, the adhesive layer is applied directly to the first surface of the electronic device, rather than being applied to the outer facing surface of the removable layer previously assembled with the electronic device.

  When the removable layer is applied to partially cover the area of the electronic device mounting location on the base insulating layer, the adhesive layer is applied to partially cover the first surface of the electronic device. It is necessary to In particular, when the electronic device is disposed so as to face the base insulating layer and bonded to the base insulating layer, a region on the second surface of the base insulating layer that is not covered by the removable layer does not contact the adhesive. In addition, the adhesive layer needs to be applied to selected areas of the electronic device. By the time the adhesive enters the B stage, the adhesive layer may be partially cured.

  The active surface or the first surface of the electronic device may be disposed so as to contact the second surface of the base insulating layer. An adhesive layer is disposed on the active surface of the electronic device, and the active surface contacts the removable layer (see FIG. 3D). An automatic pick and place system may be used to place the electronic device on the base insulating layer. To bond the electronic device to the base insulating layer, the adhesive layer may be cured. It is necessary to use a curing temperature lower than the melting temperature of the removable layer.

  In one embodiment, the base insulating layer has a first surface and a second surface (see FIG. 4A). In order to stabilize the dimensions of the insulating base layer during processing, the insulating base layer is fixed to a frame structure (not shown). In this embodiment, the removable layer is applied to the base insulating layer and cured as described above (see FIG. 4B).

  As shown in FIG. 4C, the adhesive layer is applied to the second surface of the base insulating layer toward the surface facing the outside of the removable layer. The adhesive layer may be applied as described above.

  The active surface or the first surface of the electronic device is arranged on the base insulating layer so that the active surface of the electronic device is disposed on the base insulating layer in contact with the adhesive layer (see FIG. 4D). You may arrange | position in the state which contacts a 2nd surface. An automatic pick and place system may be used to place the electronic device on the base insulating layer.

  Referring to FIGS. 5A and 5B, a low temperature sensing adhesive layer 28 is applied to the second surface of the base insulating layer. The low temperature sensitive adhesive layer bonds at least one electronic device to the base insulating layer. Low temperature sensitive adhesives may be useful when the adhesive effectively bonds the electronic device to the base insulating layer during processing and use.

  The active surface or first surface of the electronic device is the second of the base insulating layer so that the active surface of the electronic device is placed in contact with the low temperature sensitive adhesive layer (see FIG. 5 (b)). You may arrange | position in the state which contacts a surface. For example, in this case, the base insulating layer may be placed on the heating stage of an automatic pick and place system that picks up each electronic device that is a chip from a diced wafer or from a tray of individually separated chips such as waffle packs. Good. If the cold sensitive adhesive is only partially cured, the cold sensitive adhesive may be heated so that the adhesive softens and has a viscosity. The chip is then placed so that the active surface of the chip faces the second surface of the base insulating layer, so that the I / O contacts of each chip are aligned with the standard points on the base insulating layer. It arrange | positions with a 1st surface facing down. In order to bond the electronic device to the base insulating layer, the low temperature sensitive adhesive may be fully cured.

  In one embodiment, as shown in FIG. 6 (a), the low temperature sensitive adhesive is applied to the first surface of the electronic device rather than to the base insulating layer. By the time the adhesive enters the B stage, the low temperature sensitive adhesive may partially cure. The cold sensitive adhesive may be handled, processed and assembled as described above. Thereafter, the low temperature sensitive adhesive is fully cured.

  The active surface or first surface of the electronic device having the low temperature sensitive adhesive may be in contact with the second surface of the base insulating layer (see FIG. 6 (b)). In order to stabilize the dimensions of the base insulating layer during processing, the base insulating layer may be fixed to the frame structure.

  In order to recover the electronic device from the wiring structure and the base insulating layer, the sealing step may be delayed until the final processing step. However, if an unsealed electronic device is left on the base insulating layer during processing, a problem may occur in the base insulating layer with respect to patterning because an unsealed surface is not flat.

  In order to stabilize the dimensions of the base insulating layer during processing, the base insulating layer is fixed to the frame structure. In one embodiment, the frame panel 30 has a first surface 32 and a second surface 34. The frame has a surface that defines one aperture or opening 38 for each location of the electronic device on the base insulating layer (see FIGS. 7A and 7B).

  The base insulating layer may be fixed to the frame panel as shown in FIG. The frame panel stabilizes the base insulating layer during manufacture of the wiring structure instead of or in addition to the frame structure (as shown above). Further, the frame panel may improve the flatness of the unsealed surface of the base insulating layer being processed. The frame panel may be a relatively permanent part of the wiring structure. As shown in FIG. 7A, the frame panel may be sufficiently large to include a plurality of openings 38. Each opening corresponds to a different electronic device mounting location on the base insulating layer, whereby the frame panel provides stability and improved flatness for multiple electronic device mounting locations. Alternatively, the frame panel may include a single opening and be sized to provide stability and improve flatness for one electronic device mounting location on the base insulating layer.

  Suitable frame panels may be formed from metal, ceramic or polymer materials. Suitable polymeric materials may include polyimide, epoxy or epoxy mixtures. The polymeric material may include one or more reinforcing fillers. Such fillers may include fibers or small inorganic particles. Suitable fibers may be glass fibers or carbon fibers. Suitable particles may include silicon carbide, boron nitride or aluminum nitride. The frame panel may have a molded polymer structure. In one embodiment, the frame panel is a metal selected from titanium, iron, copper or tin. Alternatively, the metal may be an alloy or stainless steel or a metal composite such as Cu: Invar: Cu. The particular material from which the frame panel is formed may be selected for a particular structure based on the desired coefficient of thermal expansion, stiffness, or other desired mechanical properties. The frame panel may have a metal coating film. Suitable metals for the coating may include nickel. The frame panel may have a polymer coating. Suitable polymer coating materials may include polyimide that improves adhesion.

  The frame structure and / or frame panel may stabilize the base insulating layer during processing. However, the use of a frame structure or frame panel may be unnecessary. For example, roll-to-roll processing may not require the use of a frame structure or frame panel.

  The frame panel may have a coefficient of thermal expansion (CTE) greater than about 10 ppm / ° C. The frame panel may have a coefficient of thermal expansion (CTE) of less than about 20 ppm / ° C. In one embodiment, the frame panel may have a thickness that is equal to or close to the thickness of the electronic device.

  In one embodiment, the first surface of the frame panel is fixed to the second surface of the base insulating layer (see FIGS. 8A and 8B). The base insulating layer may be bonded to the frame panel using the adhesive layer 40. Adhesives suitable for joining the frame panel to the base insulating layer include at least the materials listed above as suitable adhesive materials. Suitable application methods include those listed above.

  Furthermore, when the adhesive layer used to bond the frame panel to the base insulating layer is the same as the adhesive layer used to bond the electronic device to the base insulating layer, the battery device and the frame panel are It may be simultaneously disposed on the base insulating layer and cured simultaneously. This will simplify the processing steps or reduce the number of processing steps. For example, as shown in FIG. 9, the second surface of the insulating base layer 14 is covered with a thermosetting adhesive layer 16, and the adhesive material is cured to the B stage. As shown in FIG. 9B, the second surface of the base insulating layer is bonded to the first surface of the frame panel 30. The electronic device 18 having the removable layer already fixed is disposed on the second surface of the base insulating layer in the opening of the frame panel 30 (see FIGS. 9C and 9D). . To bond both the frame panel and the electronic device to the base insulating layer, the adhesive layer is fully cured.

  Each opening in the frame panel may be larger in the range of about 0.2 mm to about 5 mm than the electronic device in the x and y dimensions. By increasing the size in this way, the electronic device can be easily disposed on the base insulating layer later. Alternatively, the frame panel may be disposed on the base insulating layer after the electronic device is disposed on and / or joined to the base insulating layer.

  Referring to FIG. 10A, for example, the second surface of the base insulating layer is covered with an adhesive layer, and the adhesive is cured to the B stage. As shown in FIG. 10B, the electronic device on which the removable layer is applied is disposed on the second surface of the base insulating layer. As shown in FIGS. 10C and 10D, the second surface of the base insulating layer is bonded to the first surface of the frame panel. The electronic device is disposed in the opening of the frame panel. Finally, the adhesive layer is fully cured to bond the frame panel and electronic device to the base insulating layer.

  In one embodiment, the partial structure includes a removable layer and an adhesive layer, and a barrier coating film is disposed between the removable layer and the adhesive layer to form a sandwich structure. The barrier coating may prevent migration of reactive species from the adhesive layer and may prevent reaction between the adhesive layer and the removable layer during processing. If such a reaction occurs, the interface between the removable layer and the adhesive layer will be weakened or a defect will be formed between the layers. For example, during high temperature processing such as curing, the thermosetting adhesive layer may react with the thermoplastic material of the removable layer.

  After the removable layer is applied to the electronic device, or after the insulating base layer and the removable layer are cured, the barrier coating film is placed on the surface facing the outer side of the removable layer (on top of the removable layer). It may be applied. The barrier coating film may be either an organic layer or an inorganic layer. In embodiments in which an organic barrier coating is used, the barrier coating is made into a base insulation by a method indicated herein as being suitable for applying either an adhesive layer or a removable layer. It may be applied to a layer or an electronic device. Application methods include, but are not limited to, chemical vapor deposition, plasma deposition or reactive sputtering. In embodiments where an inorganic barrier coating is used, the barrier coating may be deposited by, for example, CVD, vapor deposition, or sputtering. When the barrier coating is applied to the surface of the electronic device, the barrier coating may be applied at the wafer level at the stage where the wafer processing is completed and before wafer sawing is performed. Alternatively, the barrier coating film may be applied to individually separated chips after wafer sawing.

The barrier coating may include one or more organic materials selected from polyolefins, polyesters, or amorphous hydrogenated carbon. Other suitable barrier coatings may be formed from inorganic materials such as Ta ₂ O ₅ , Al ₂ O ₃ , Sb ₂ O ₃ , Bi ₂ O ₃ , WO ₃ or ZrO ₂ .

  In one embodiment, the electrical connection between the electronic device and the base insulating layer is formed after the electronic device is bonded to the base insulating layer. In particular, an electrical connection is formed between an I / O contact disposed in the electronic device and an electrical conductor disposed in the base insulating layer.

  Referring to FIG. 11, suitable electrical conductors 40 that may be disposed on the base insulating layer include pads, pins, bumps or solder balls. The electrical connection between the base insulating layer and the electronic device may be a structure selected based on application specific parameters. For example, apertures, holes or vias 42 may be formed through the base insulating layer, adhesive layer and removable layer to one or more I / O contacts on the electronic device (see FIG. 11). . In one embodiment, the via size may be defined to be a micro via. Vias may be formed by laser ablation, mechanical drilling, punching, wet chemical etching, plasma etching or reactive ion etching.

  When vias are formed by laser ablation technology, the base insulating layer may be supported by a frame structure or placed in an automated laser system after being turned over. The laser system may be programmed to perform laser ablation on the base insulating layer at selected locations. This treatment forms blind hole vias that penetrate the base insulating layer, the adhesive layer, and the removable layer to the plurality of I / O contacts 24 on the electronic device 18. A smear removal process or a scum removal process that removes residual ash and residual adhesive layers inside the vias to expose I / O contacts on the electronic device may be performed after laser ablation as needed. This step may be performed by reactive ion etching (RIE), plasma clean or wet chemical etching. A trace, power plane, or ground plane may be formed on the first surface of the base insulating layer as necessary.

  Referring to FIG. 11B, the conductive material indicated by reference numeral 44 in the drawing extending to the I / O contact on the electronic device and the first surface of the base insulating layer 10 is disposed in the via. Also good. The conductive material may be a conductive polymer and may be deposited by jetting or screening. Examples of suitable conductive materials may include epoxies, polysulfones or polyurethanes with metal particle fillers. Suitable metal particles include silver and gold. Other suitable metals may include Al, Cu, Ni, Sn and Ti. Instead of the polymeric material containing the filler, a polymer that is inherently conductive may be used. Suitable conductive polymers include polyacetylene, polypyrrole, polythiophene, polyaniline, polyfluorene, poly-3-hexylthiophene, polynaphthalene, sulfided poly-p-phenylene and poly-p-phenylene vinylene. When viscosity and stability become a problem, a conductive filler may be filled in a polymer that is inherently conductive in order to further improve the conductivity.

  When the conductive material is a metal, the conductive material may be deposited by a method that includes one or more of sputtering, vapor deposition, electroplating, or electroless plating. In one embodiment, the first surface of the base insulating layer and the exposed surface of the via extending to the I / O contact on the electronic device are metallized using a combined sputter plating and electroplating sequence. The base insulating layer is disposed in the vacuum sputtering system with the first surface of the base insulating layer and the via exposed to the vacuum sputtering system. In order to remove residual adhesive material and native metal oxide, a backsputter process sputter etches the exposed I / O contacts of the device. Further, in the back sputtering process, etching is performed into the surface of the base insulating layer. Sputter etching of the metal I / O contact reduces the contact resistance of the subsequent metallization process, while etching of the base insulating layer improves the adhesion of the metal to the first surface of the base insulating layer.

  As shown in FIG. 11 (b), a seed metal layer 44 is sputter deposited on the first surface of the base insulating layer, the sidewalls defining the vias and the exposed I / O contacts. A double metal system containing a barrier metal such as Ti or Cr and a non-barrier metal such as Cu or Au may be used. The barrier metal can be plated to a thickness in the range of about 1,000 mm to about 3,000 mm, and the non-barrier metal can be plated to a thickness in the range of about 0.2 μm to about 2.0 μm. In the metal vapor deposition step, the metal wiring portion may be formed on the first surface of the base insulating layer, that is, the surface not on the element side.

  Following the sputtering step, as shown in FIG. 11C, a relatively thick layer of a non-barrier seed metal layer is electroplated on the first surface of the base insulating layer. A suitable metallization patterning process may include a semi-additive process or a pattern plate-up process as shown in FIG. The metallized surface of the base insulating layer, including the via sidewalls, is electroplated with metal to form a layer having a thickness in the range of about 2 μm to about 20 μm. Referring to FIG. 11 (c), a photomask material is disposed to cover the first surface of the base insulating layer, and the photomask material is photopatterned to expose selected regions of the first surface. The The regions on the first surface of the base insulating layer where it is desired to retain the metal, such as wiring traces, I / O contacts and vias, remain coated with photoresist, and the base insulating surface where the metal is removed. The area is exposed and not covered. A plurality of metal wet etch baths remove the plated metal and sputtered metal in the exposed surface region of the base insulating layer, while the remaining region is protected from the wet etchant by the mask material. After completion of the etching process, the remaining photoresist material is removed. By removing the photoresist material, a desired metallization pattern as shown in FIG.

  In one sequence, a subtractive metal patterning process is used. In this method, a photomask material is placed over the first surface of the base insulating layer, and then the photomask material is photopatterned to expose selected regions of the first surface. Areas on the first surface of the base insulating layer where it is desired to retain metal, such as wiring traces, I / O contacts and vias, remain coated with photoresist, but it is desirable to remove the metal. The area of the surface of the base insulating layer remains uncovered as shown in FIG. The exposed metallized region of the first surface of the base insulating layer including the via sidewalls is electroplated to a thickness in the range of about 4 μm to about 20 μm. Since the plated metal has sidewalls that follow the straight sidewalls of the patterned photoresist, the thickness of the photoresist should not exceed the thickness of the plated metal. After completion of the plating process, the remaining photoresist material is removed. As a result, as shown in FIG. 11D, a metallized region on the first surface of the base insulating layer that is not plated with the seed metal is obtained. In order to leave the desired metallization pattern, the exposed seed metal may be removed by a plurality of standard wet metal etch baths. A soldering process may be used to further form an electrical connection between the base insulating layer and the electronic device.

  As a result of the processing steps described above, electrical connection from the first wiring layer 48 and the first wiring layer to the I / O contact of the electronic device is completed. Complete routing for all required chip I / O contacts in wiring to one or more complex electronic devices, including semiconductor chips such as microprocessors, video processors and ASICs (Application Specific Integrated Circuits) Therefore, an additional wiring layer may be required. In the case of such an electronic device, one or more additional wiring layers may be formed on the first surface of the base insulating layer. In the case of a simpler electronic device in which route definition is not so complicated, only one wiring layer has to be formed.

  In one embodiment, the additional wiring layer is formed by bonding an additional insulating layer 50 to the first wiring layer. In one embodiment shown in FIG. 12 (a), the additional insulating layer has a first surface 52 and a second surface 54 and is covered by an adhesive layer 56. Adhesives suitable for use in the present invention include materials previously indicated as being suitable adhesive materials. When the adhesive layer includes a thermosetting material, the adhesive is cured to the B stage after the adhesive layer is applied to the additional insulating layer.

  Suitable methods for applying the adhesive layer to the additional wiring layer include spray coating, spin coating, roll coating, meniscus coating, dip coating, transfer coating, jetting, drop dispensing, pattern print deposition or dry film laminating. Including. The adhesive layer may have a thickness greater than about 5 μm. In one embodiment, the removable layer has a thickness in the range of about 5 μm to about 10 μm, about 10 μm to about 20 μm, about 20 μm to about 30 μm, about 30 μm to about 40 μm, or about 40 μm to about 50 μm, or greater than about 50 μm. It may have a thickness. In another embodiment, the adhesive layer may be a pre-fabricated natural adhesive film that is applied to the surface of the additional insulating layer.

  Referring to FIG. 12B, the second surface of the additional insulating layer is disposed so as to be in contact with the first surface (the side that is not the component side) of the base insulating layer. In order to bond the additional insulating layer to the base insulating layer and the wiring layer 48, the adhesive layer is completely cured. In one embodiment, the additional insulating layer is bonded to the first surface of the base insulating layer using a heated vacuum lamination system.

  The electrical conductor 40 on the additional insulating layer is electrically connected to the electrical conductor 40 on the base insulating layer. For example, as shown in FIG. 12C, a via that penetrates through the additional insulating layer and the adhesive layer to reach a selected electrical conductor on the base insulating layer may be formed. The same process steps used to form the vias in the first wiring layer and deposit the conductive material as described above to form the conductive vias in the additional insulating layer and the adhesive layer. May be used (see FIG. 12D).

  In one embodiment, the first surface of the additional insulating layer is metallized to complete the second wiring layer using the metallization and patterning steps described above for the first wiring layer. Similarly, a plurality of additional wiring layers may be formed.

  As shown in FIGS. 12D and 13, the plurality of wiring layers cooperate to define the wiring structure 60. The wiring structure has a first surface 62 and a second surface 64. By covering the first side of the structure with a dielectric mask material or solder mask material 68 to passivate any metal trace and define the contact pads used for the structure or package I / O contact The wiring structure may be completed. The package I / O contact may have an additional metal deposition film such as Ti: Ni: Au applied to the exposed contact pad to form a more robust I / O contact. The additional metal vapor deposition film may be applied by electroless plating. Pins, solder balls or lead wires may be attached to the I / O contact pads, or may be left as they are so as to form a pad array. FIG. 13 shows a wiring assembly 60 having an array of solder balls as in the case of a ball grid array. Other wiring structures may be used. For example, the wiring structure may have an array of pins as in the case of a pin grid array.

  Either a single wiring layer or a wiring structure including a plurality of wiring layers may be used, but when the wiring structure is completed, whether or not all wiring is correct is determined by a standard electrical test station. Determined. Correct means that there is no open circuit or short circuit in the circuit. If testing indicates that the wiring structure is defective or another part of the wiring structure is defective, a useful electronic device may be retrieved from the package containing the defect. Alternatively, if the electronic device is found to be defective, the defective device may be removed from the wiring structure and replaced with a new device.

  In one embodiment, the removable layer may have a softening temperature or melting point. The electronic device may be recovered from the wiring structure by heating the removable layer to its softening temperature or melting point. When the temperature is reached, the electronic device that is peeled or removed from the base insulating layer and the wiring structure can be recovered. In order to soften or melt the removable layer, the removable layer is exposed to a heat source. Using this technique, the wiring structure may be stripped from the electronic device while the electronic device is firmly secured by the holding device. Suitable holding devices may employ vacuum clamps or mechanical clamps. The clamp may grip the edge of the wiring structure and remove or strip the wiring structure from the electronic device.

  The removable layer allows the electronic device to be recovered without damaging the electronic device or elements on the active surface of the electronic device. Due to the use of low K (dielectric constant) interlayer dielectrics, mechanical strength is low, and with the advent of damaged semiconductor devices, it is particularly important to be able to recover such electronic devices.

  In another removal method, the wiring structure may be mounted on a heating stage such that the secondary heating source locally heats the electronic device and the area surrounding the device. The removable layer is heated to the softening temperature or melting point. If the removable layer comprises a thermoplastic polymer or a thermosetting polymer, the removable layer may be softened or melted by exposing the removable layer to a temperature determined by the material properties of the polymer. A suitable temperature range may be in the range of about 250 ° C to about 350 ° C.

  When an electronic device that is functioning intact is separated from a defective base insulating layer, the melting point of the removable layer must be below the maximum damage threshold temperature of the electronic device. The maximum damage threshold temperature of an electronic device is the highest temperature at which the electronic device (including all circuits on the device) can be exposed without damaging the electronic device. On the other hand, if it is desired to remove the defective electronic device from the base insulating layer that is functioning without damage, the melting point of the removable layer must be lower than the maximum damage threshold temperature of the base insulating layer. I must. The maximum damage threshold temperature of the base insulating layer (including all circuits on the layer) is the highest temperature at which the base insulating layer can be exposed without damaging the component. Therefore, any part of the defective electronic device or other defective parts may be removed from the wiring structure.

  In one embodiment, the wiring structure is a relatively fine pitch (about 50 μm to about 1,000 μm) solder to electrically connect the electronic device to the base insulating layer to define and form the wiring structure. Includes flip chip or chip scale electronic devices that utilize an array of spheres. The removable layer needs to be applied before applying the underfill. If the removable layer is not applied before applying the underfill, the electronic device can be removed when the solder mounted electronic device is found to be defective before the underfill cures, but after the underfill has cured The electronic device cannot be easily removed. Underfill may seal the solder balls after reflow and electrically connect the electronic device to the solder pads of the wiring structure. Therefore, the underfill is not bonded to the substrate, but is bonded to the removable layer. By applying a removable layer below the electronic device mounting location, the electronic device can be removed after underfill cure has occurred.

  In one embodiment, the wiring structure may be attached to a heating stage. The secondary heating source locally heats the electronic device and the area surrounding the device. The solder joints that attach the removable layer and the electronic device to the wiring structure are heated to their softening point or melting point. As a result, the removable layer and the electronic device are peeled off, and the electronic device can be removed from the mounting location without any influence on the thermosetting underfill. The area where the device was previously mounted may be cleaned to remove residue or debris. Finally, a new electronic device with solder balls may be mounted on the wiring structure, soldered and underfilled to complete the replacement of the defective part.

  When the electronic device is electrically attached to the wiring structure by a solder connection such as a solder ball or a conductive polymer lead, the electrical connection and the removable layer have a melting point to remove the electronic device from the wiring structure. Or it needs to be heated to the softening point. In order to melt or soften the conductive polymer material so as to peel off the electronic device, the physical connection between the electronic device formed by the conductive polymer material and the wiring structure may be heated. Alternatively, the electrical connection may be physically broken if possible after the removable layer is melted or softened.

  By employing the embodiments disclosed herein, chip-on-flex, plastic high density interconnect (HDI), and high I / O count processor chips will benefit. In the chip-on-flex process, it is necessary to manufacture a complicated wiring structure after the electronic device is bonded to the base insulating layer. Manufacturing is complicated because the number of layers required to define the paths of many chip I / O pads is large and each wiring layer required is complex. However, the defect rate for each wiring structure is as high as about 2% to about 10%. Unless the repair process is available, the yield reduction of the complicated wiring structure is accompanied by the disadvantage that the expensive processor chip has to be discarded. Recovery by one or more of the disclosed methods is stable at normal operating temperatures and can withstand high solder reflow temperatures, but if the electronic device needs to be recovered from the wiring structure A relatively low stress recovery process of the joint that can be removed can be provided.

  In one embodiment, sealing may be delayed until the final processing step to allow the electronic device to be removed from the wiring structure. After the wiring layer is completed, a wiring structure test is performed. If the wiring structure and the electronic device are found to be free of defects, the area surrounding the electronic device may be sealed to further protect the electronic device and the wiring structure from moisture and thermomechanical stress. In order to completely embed the base insulating layer and the electronic device, the base insulating layer and the exposed electronic device may be sealed with a sealing material 70 (see FIG. 13). In another embodiment, the base insulating layer and the exposed electronic device may be partially sealed to embed the base insulating layer and the electronic device (see FIG. 13). In one embodiment, a potting or molding process is used to perform the sealing. Suitable molding processes may include casting, transfer molding or compression molding. A dam and fill sealing method is preferably utilized.

  Sealing materials that may be used include thermoplastic polymers and thermosetting polymers. Suitable aliphatic and aromatic polymers are polyetherimide, acrylic resin, polyurethane, polypropylene, polysulfone, polytetrafluoroethylene, epoxy, benzocyclobutene (BCB), room temperature vulcanization (RTV) silicone and urethane, polyimide , Polyetherimide, polycarbonate, silicone and the like. In one embodiment, the encapsulant is a thermosetting polymer because a relatively low curing temperature can be utilized. The sealing material may include a filling material. The type, size and amount of filler material may be used to adapt various molding material properties such as thermal conductivity, coefficient of thermal expansion, viscosity and water absorption. For example, the materials may include particles, fibers, screens, mats or plates of inorganic particles. Suitable filler materials may include glass, silica, ceramic, silicon carbide, alumina, aluminum nitride, boron nitride, gallium and other metals, metal oxides, metal carbides, metal nitrides, or metal silicides. Other suitable filler materials may include carbon-based materials.

  When a frame panel is used, apply the frame panel before mounting the electronic device (see FIG. 9), after mounting the electronic device (see FIG. 10), or after completing the wiring structure (see FIG. 14). Also good. In the method in which the frame panel is applied after the completion of the wiring structure, an adhesive is applied to the main surface of the frame panel, and the frame panel is bonded to the second surface of the wiring structure. In all of these frame panel mounting methods, there may be a gap or moat region between the inner edge of each opening in the frame panel and the outer edge of the electronic device disposed in the opening. This void may remain unfilled or may be completely or partially filled with a sealing material. The gap between the inner edge of the frame panel opening and the outer edge of the electronic device may be partially filled in a range from about 10% fill to about 90% fill. The sealing material may be cured. In certain embodiments, it may be beneficial to cure the encapsulant and the adhesive layer simultaneously.

  After the base insulating layer and the exposed electronic device are sealed, a lid / thermal spreader 72 may be bonded to the second surface of the electronic device to protect the electronic device from heat. The lid / thermal spreader is joined by a thermal interface material (TIM) 74. The lid / thermal spreader may be bonded to the second surface of the frame panel using an adhesive 76. Alternatively, for high power devices with dissipation of about 5W to about 100W or more, the back side of the electronic device may remain exposed to help remove heat during device operation.

  The embodiments described herein are examples of compositions, structures, systems and methods having elements corresponding to the elements of the invention recited in the claims. The description herein will enable one of ordinary skill in the art to make and use embodiments having alternative elements that likewise correspond to the elements of the invention recited in the claims. Accordingly, the scope of the present invention includes other compositions, systems, and methods that include compositions, structures, systems, and methods that do not differ from the terms of the claims and that have insubstantial differences from the terms of the claims. Further included. Although only certain features and embodiments have been illustrated and described herein, many variations and modifications will be apparent to those skilled in the art. The appended claims encompass all such variations and modifications.

1 is a cross-sectional side view illustrating an electronic device bonded to a base insulating layer according to an embodiment of the present invention. 6 is a cross-sectional side view illustrating an electronic device bonded to an insulating base layer according to another embodiment of the present invention. FIG. 6 is a cross-sectional side view illustrating an electronic device bonded to an insulating base layer according to another embodiment of the present invention. FIG. 6 is a cross-sectional side view illustrating an electronic device bonded to an insulating base layer according to another embodiment of the present invention. FIG. 6 is a cross-sectional side view illustrating an electronic device bonded to an insulating base layer according to another embodiment of the present invention. FIG. 6 is a cross-sectional side view illustrating an electronic device bonded to an insulating base layer according to another embodiment of the present invention. FIG. It is the top view which showed the frame panel. 4 is a cross-sectional side view illustrating a frame panel bonded to a base insulating layer according to another embodiment of the present invention. FIG. 6 is a cross-sectional side view illustrating an electronic device bonded to a base insulating layer in a frame panel according to another embodiment of the present invention. FIG. FIG. 6 is a cross-sectional side view showing an electronic device and a frame panel bonded to a base insulating layer according to another embodiment of the present invention. It is the cross-sectional side view which showed the formation of via | veer and metallization of a base insulating layer concerning one Embodiment of this invention. 6 is a cross-sectional side view showing an additional base insulating layer bonded to a wiring layer according to another embodiment of the present invention. FIG. It is the cross-sectional side view which showed the wiring structure manufactured according to another embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Base insulating layer, 12 ... 1st surface of base insulating layer, 14 ... 2nd surface of base insulating layer, 16 ... Adhesive layer, 18 ... Electronic device, 20 ... 1st surface of electronic device, 22 ... second side of electronic device, 24 ... I / O contact, 26 ... removable layer, 28 ... cold sensitive adhesive layer, 30 ... frame panel, 38 ... aperture, 40 ... electrical conductor, 42 ... via, 44 ... Conductive material, 48 ... wiring layer, 60 ... wiring structure, 68 ... solder mask material

Claims (10)

A base insulating layer having a first surface and a second surface;
An electronic device having a first surface and a second surface and secured to the insulating base layer;
An adhesive layer disposed between the first surface of the electronic device and the second surface of the base insulating layer;
A removable layer disposed between the first surface of the electronic device and the second surface of the base insulating layer, the base insulating layer being interposed between the electronic device and the electronic device. And the removable layer is capable of peeling the base insulating layer from the electronic device.   The electronic component according to claim 1, wherein the electronic device can be recovered from the insulating base layer without damaging the electronic device by the removable layer.   An I / O contact on the first surface or the second surface of the electronic device; and an electrical conductor disposed on the first surface or the second surface of the base insulating layer. The electronic component according to claim 1, further comprising: the I / O contact electrically connected to the electric conductor.   The electronic component of claim 1, wherein the removable layer includes a plurality of partial layers that are separable from each other to facilitate removal of the electronic device from the insulating base layer. The electrical connection structure further comprises:
At least one via extending from the first surface of the base insulating layer to an I / O contact on the first surface of the electronic device;
The electronic component according to claim 1, further comprising: a conductive material disposed in at least a part of the via and extending through the via to the I / O contact on the electronic device.   The frame panel further comprising a first surface, a second surface, and at least one aperture corresponding to an electronic device mounting location on the base insulating layer, wherein the first surface of the frame panel includes the first surface, The electronic component according to claim 1, wherein the electronic component is fixed to the second surface of the base insulating layer.   The removable layer has a melting point that is lower than a maximum damage threshold temperature of the electronic device, and the removable layer is exposed to a temperature that is higher than the melting point but lower than the maximum damage threshold temperature of the electronic device. The electronic component of claim 1, wherein the electronic device is removed from the second surface of the base insulating layer.   The removable layer has a melting point lower than a maximum damage threshold temperature of the base insulating layer and is higher than the melting point but lower than the maximum damage threshold temperature of the base insulating layer. 2. The electronic component according to claim 1, wherein the electronic device is removed from the second surface of the base insulating layer.   The removable layer is dissolvable in a solvent, the electronic device is chemically resistant to contact with the solvent, and the electronic device when the removable layer is exposed to the solvent The electronic component according to claim 1, wherein the electronic component is removed from the second surface of the base insulating layer.   The removable layer is soluble in a solvent, and the wiring structure component except the electronic device has chemical resistance to contact with the solvent, and the removable layer is exposed to the solvent. The electronic component according to claim 1, wherein the electronic device is removed from the second surface of the base insulating layer.

Images