JP3164325U - Uniform body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressurizing force homogenizing body for heating and pressurizing and joining a large number of parts related to joining. A pressurizing uniform body that presses an object to be pressed with a uniform force, the pressurizing uniform body having a highly heat-resistant resin layer serving as a pressurizing surface on a hard substrate having good thermal conductivity. The high heat-resistant resin is a polymer composition that can be linked by a covalent bond generated by an addition reaction to form a three-dimensional structure, and has a crosslinked structure of siloxane (Si—O—Si conjugate). The molecular weight is 20,000 to 800,000, wherein at least one first organosilicon polymer having a siloxane bond and at least one second organosilicon polymer having a linear linking structure with siloxane are linked by a siloxane bond. It is a synthetic polymer compound containing at least one third organosilicon polymer. [Selection] Figure 1A

Description

  For example, the present invention relates to a pressurizing uniform body used for simultaneously bonding a plurality of semiconductor elements to a substrate by heating and pressing, or for simultaneously bonding a hermetic sealing lid to a plurality of packages.

For mounting semiconductor elements that generate heat, Au eutectic solder having a high melting point such as AuSn or AuGe is used. Au eutectic solder is used when a semiconductor element is bonded to a package substrate or when a lid is bonded to hermetically seal the package. The Au eutectic solder needs to be sufficiently wetted to the joint surface when it is in a solution state at the eutectic melting point, and if the joint surface is contaminated or has an oxide film, the wettability deteriorates. In general, a semiconductor element or a lid is placed on a substrate or a package so as to be rubbed (scrubbed) on the bonding surface, and the oxide eutectic film on the bonding surface is broken so that the Au eutectic solder in a solution state is sufficiently wetted. It is work that requires skill.
On the other hand, metal nanoparticles have been proposed as an alternative joining material (for example, Patent Document 1). Examples of metals include Au, Cu, and Ag. These metal nanoparticles are dispersed in a solvent and applied to a bonding surface by applying a paste or slurry, and a semiconductor element or lid is simply heated and pressed onto a substrate or package. Can be joined. No ultrasonic or scrubbing is required. It is said that heating is relatively low temperature and bonding is possible at 200 ° C to 300 ° C. Although cleaning of the joint surface is necessary, it is not a work that requires skill in particular. In order to mount a plurality of parts at once, it is only necessary to uniformly heat and press uniformly, and a process with high productivity can be constructed.

  As a method for uniformly applying pressure to an object to be pressurized, Patent Document 2 proposes a structure of a pressure equalizing member (FIG. 7). A low melting point metal or alloy 14 is placed in the fluid container 13 and is sealed with a thin metal foil 15 such as an aluminum foil. When indium, lead, etc. are used as the low melting point metals and pressed against the object to be pressed by heating and pressurization above the melting point, even if the object to be pressed has irregularities, the fluid adheres to the irregularities uniformly. It can be pressurized. However, if there is a protrusion on the object to be pressed or if there is a small substance that becomes a protrusion, the metal foil will be pierced, and the metal solution will flow out, which will be a very dangerous operation. Needless to say, in order to repeatedly use the fluid container, sufficient attention must be paid to scratches and minute cracks on the metal foil. In order to avoid this, the metal foil is made sufficiently thick. However, if this is done, the adhesiveness to the pressed article with unevenness is impaired, and uniform pressurization becomes insufficient. It is difficult to repeatedly use the fluid container with this structure.

JP 2006-202938 A Japanese Patent No. 431873

  As described above, the conventional technology has a structure in which a low melting point metal is contained in a container and heated to contain a solution in a thin metal foil, so it cannot be said to be a safe operation and can be used repeatedly. It cannot be tolerated.

  The purpose of the present invention is to join a plurality of parts and the same number of parts, or to join a plurality of parts to a substrate at the same time. A pressurizing uniform body suitable for joining is provided.

  The pressure equalizing body of the present invention is used by being incorporated in a press apparatus or a substrate bonding apparatus having a heating and pressing mechanism. Specifically, when a plurality of lids are collectively bonded to a package substrate in which a plurality of packages are formed into a sheet shape and hermetic sealing is performed, the lids are temporarily fixed to the packages in advance by pick and place. The package substrate is placed on a table of a press device, and the pressure uniformizing body is placed on the package substrate and pressed by a surface plate that is driven up and down. The pressure uniformizing body may be attached to a surface plate. The same process can be performed when a plurality of semiconductor elements are bonded to the mounting substrate.

  The pressure uniformizing body has a high heat-resistant resin layer that serves as a pressure surface on a hard substrate with good thermal conductivity, and the high heat-resistant resin is linked by a covalent bond generated by an addition reaction to form a three-dimensional structure. At least one first organosilicon polymer having a crosslinked structure with siloxane (Si—O—Si conjugate) and at least one having a linear linked structure with siloxane A synthetic polymer compound containing at least one third organosilicon polymer having a molecular weight of 20,000 to 800,000, which is linked to the second organosilicon polymer by a siloxane bond. .

  According to Japanese Patent Laid-Open No. 2006-206721, the above synthetic polymer compound remains flexible even when thermally cured at 200 ° C., and does not proceed even if left at a temperature of 300 ° C. for a long time, and further has a heat resistance of 400 ° C. It is said that there is. A typical product is commercially available as Nanotech Resin KA-100 (ADEKA). As described above, even an uneven surface can be sufficiently brought into contact with pressure.

  A polyimide resin layer is formed on the high heat resistant resin layer to form a pressure surface. A high heat resistant resin (synthetic polymer compound) is flexible as described above, but a polyimide resin increases in hardness and becomes an elastic body when cured. In the case of a module in which a plurality of semiconductor elements are mounted on a mounting board, the semiconductor elements that require pressure are sufficiently small relative to the area of the mounting board. By forming the polyimide resin layer, a sufficient pressure can be applied even to a small object to be pressed using its elasticity.

  Further, the polyimide resin layer has a structure in which a large number of small-diameter cylinders are projected, and this is used as a pressure surface. This pressure surface is a sword-like shape with small protrusions. When the lid is joined to the package, if the lid has an inclination, the lid may be displaced and joined. When this pressing surface is used, the inclination is corrected by at least one point pressing, and when the parallelism of the lid with respect to the package comes out, the multipoint pressing is performed, so that the positional deviation is suppressed to the minimum.

  Furthermore, the hard substrate has a cavity, and the pressing surface is in the cavity. By doing so, the flexible high heat-resistant resin cannot be extended laterally at the time of pressurization, so that the pressure can be efficiently transmitted to the object to be pressed.

  As an effect of the present invention, by using a flexible high heat-resistant resin for the pressure uniformizing body, it can sufficiently adhere to a pressed object having poor flatness (with unevenness), and a uniform pressing can be safely performed. It becomes possible.

Sectional view of a pressure uniformizing body according to an embodiment of the present invention Sectional drawing of the pressurization uniform body which concerns on embodiment of this invention Sectional drawing of the pressurization uniform body which concerns on embodiment of this invention Sectional view of a pressure uniformizing body according to an embodiment of the present invention Sectional view of a pressure uniformizing body according to an embodiment of the present invention Sectional view of a pressure uniformizing body according to an embodiment of the present invention Diagram showing package substrate and lid Diagram showing the heating and pressurizing device The figure which shows the joining state using the pressurization equalization body which concerns on embodiment of this invention Conventional pressure equalization body

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1A shows a cross-sectional view of a pressure equalizing body 1 according to the present invention. A high heat resistant resin is formed on the hard substrate 2 to form a high heat resistant resin 3 pressure surface. The hard substrate 2 preferably has good thermal conductivity, and is preferably a metal plate such as aluminum, stainless steel or copper alloy, more preferably a Si single crystal substrate, a columnar Si substrate or a SiC polycrystalline substrate having a smaller thermal expansion coefficient than the metal. It is. The high heat-resistant resin 3 is a polymer composition that can be linked by a covalent bond generated by an addition reaction to form a three-dimensional structure, and has a crosslinked structure of siloxane (Si—O—Si conjugate). A molecular weight of 20,000 to 800,000, wherein at least one first organosilicon polymer having a siloxane bond and at least one second organosilicon polymer having a linear linking structure with siloxane are linked by a siloxane bond. A synthetic polymer compound containing one or more of certain third organosilicon polymers is most desirable. Nanotechresin KA-100 (trademark ADEKA) is a representative high heat resistant resin using this synthetic polymer compound. Nanotech Resin KA-100 has a heat resistance of 400 ° C., and has a characteristic that it does not lose its flexibility even after a long-time heat treatment (Japanese Patent Laid-Open No. 2006-206721). If this soft rubber elasticity characteristic is utilized, a pressurization surface can fully contact also with an uneven surface. The thickness of the high heat-resistant resin layer is preferably determined by the degree of unevenness of the surface of the object to be pressed to be pressurized and the height variation of the parts to be bonded. For example, if the height variation of the parts is several hundred microns, the thickness of the high heat-resistant resin layer needs to be about 1 mm, and if it is several tens of microns, the thickness of the resin layer is sufficient if it is several hundred microns.

  FIG. 4 shows a specific application example of the pressure equalizing body of the present invention. The lid 11 is joined to the package substrate 9 in which eight packages are formed into a sheet shape. Metal nanoparticles 11 are formed on the upper surface of the package as a bonding material with the lid, and Au, Ag, Cu, or the like can be used as the metal. These metal nanoparticles are commercially available as pastes or slurries dispersed in a solvent, and a coating film can be formed. Since metal nanoparticles have a high binding force, they can be coated with an organic medium to weaken the binding force. As shown in FIG. 5, the lid 11 previously placed on the package substrate 9 is pressed by a heating and pressing device. The bonding temperature is 200 to 350 ° C., and the pressure is several tens of MPa. This is because when the solvent is volatilized by heating, the metal nanoparticles start to bond to each other and eventually become bulky, thereby completing the bonding. The package substrate 9 is formed with a groove or the like so as to be able to break the chocolate, and is divided into individual products after the joining of the lid 11 is completed.

  The present invention includes the modification of FIG. 1B. This is formed by separating the high heat resistant resin layer 17 into a hard substrate. The package 10 of FIG. 4 has a cavity 18 on which a semiconductor element is mounted. The dimension of the separated high heat resistant resin layer 17 may be determined by the cavity dimension.

  FIG. 6 is a schematic view showing a state of pressurization using the pressure uniformizing body 1 (FIG. 1A). Since the high heat-resistant resin 3 has flexibility, it is pressed almost in close contact with the uneven package substrate 8. However, as the pressurization is increased, the high heat-resistant resin is extended in the lateral direction due to its flexibility. In metal nanoparticle bonding, the required pressure differs depending on the type of metal, and there are cases where it is insufficient for metals that require strong pressurization. On the other hand, the flexibility of the synthetic polymer compound can be adjusted by changing the molecular weight (Japanese Patent Laid-Open No. 2006-206721), but there is a possibility that the advantages and disadvantages may arise for the purpose of the present invention. In the present invention, the necessary pressure is secured by taking measures against the pressure uniformizing body.

  FIG. 1C shows a structure in which a cavity is provided in the hard substrate 2 of FIG. 1A and a high heat-resistant resin 3 is formed in the cavity. By making the dimensions of the cavities substantially match the dimensions of the package substrate 9, there is no escape space for the high heat-resistant resin 3, and the pressure can be efficiently applied.

  Another embodiment is shown in FIG. This is the one in which the polyimide resin layer 6 is formed on the high heat resistant resin 3, and is effective when the area of the object to be pressed for bonding is small. For example, in the package shown in FIG. 4, the part to be joined is the lid 12, but when the area of the lid is much smaller than the area of the package, sufficient pressure can be applied to the lid due to the flexibility of the high heat resistance resin. Disappear. Since the polyimide resin has a heat resistance of 400 ° C. and is hardened by thermosetting, sufficient pressurization can be secured by using the hard elastic polyimide resin layer 6 (thin film, film). There are various types of modules for mounting multiple semiconductor elements on a mounting board, including types, and cannot be explained in general. However, the common area is that the area of the semiconductor element is equivalent to the area of the mounting board. It will be smaller. Since only the semiconductor element needs to be pressurized and is convex with respect to the mounting substrate, the pressure can be sufficiently transmitted by utilizing the hard elasticity of the polyimide resin layer. Note that the thickness of the polyimide resin is not particularly limited as long as it is set to a thickness that can be brought into contact with the concavo-convex surface and that can ensure pressurization to the convex surface. That is, it should be determined by the specific state of the object to be pressed. Incidentally, a polyimide resin film having a thickness of several tens of μm is commercially available, and a film having this thickness is easily available.

  Another embodiment of the present invention is shown in FIG. 3A. This is made by forming a large number of small-diameter cylinders 8 made of polyimide resin in a sword-like shape on a flexible high heat-resistant resin layer 3. The effect of this embodiment is effective when the lid is inclined in the package substrate 9 and the lid 11 shown in FIG. 3A. When the lid is placed on the package by pick and place, the lid is temporarily fixed to the metal nanoparticle film formed of paste or slurry. The position of the temporarily fixed lid can be accurately placed on the package, but a lid with an inclination also appears. The tilted lid is corrected by at least one point pressing, and can be pressed by multipoint pressing as it becomes parallel to the package surface. The reason why this is possible is that both the temperature and the pressure are required for the particle bonding of the metal nanoparticles, and the particle bonding is not completed (bulked) only by the temperature. In order to form a small-diameter cylinder, a photosensitive polyimide resin is applied to a pre-cured high heat resistant resin surface, a small-diameter pattern is exposed to a mask, and developed. Then, it is cured by heat. 3B also has the same effect as that shown in FIG. 1B.

  The dimensions of the small-diameter cylinder are not particularly specified. The object to be pressed which is the subject of the present invention should be determined according to its size in order to be widely applicable from small to large.

  The above has described an example in which a plurality of lids are bonded together and hermetically sealed on the package substrate. However, any mounting that can be bonded and bonded at a temperature at which the heat resistance of the high heat resistant resin is not impaired can be applied. Thus, a module that collectively bonds (adheres) many semiconductor elements to a mounting substrate is no exception.

  If the pressurization uniform body of the present invention is used, it is possible to sufficiently press the object to be pressed even if there is unevenness or inclination, and it is possible to construct a process with high productivity and high safety.

1, 4, 7, 9 Applied pressure uniform body 2, 5 Hard substrate 3 High heat resistance resin 6, 8 Polyimide resin layer 10 Package substrate 11 Metal nanoparticle film 12 Lid 13 Heating and pressing apparatus surface plate 14 Fluid container 15 Low melting point metal 16 Metal foil 17 Isolated high heat resistant resin 18 Package cavity

Claims (4)

  A pressurizing uniform body that presses an object to be pressed with a uniform force, the pressurizing uniform body having a high heat-resistant resin layer serving as a pressurizing surface on a hard substrate having good thermal conductivity, The heat-resistant resin is a polymer composition that can be linked by a covalent bond generated by an addition reaction to form a three-dimensional structure, and has at least a crosslinked structure of siloxane (Si—O—Si conjugate). A third molecular weight having a molecular weight of 20,000 to 800,000, wherein one kind of first organosilicon polymer and at least one second organosilicon polymer having a linearly linked structure of siloxane are linked by a siloxane bond. A pressurizing force homogenized body, which is a synthetic polymer compound containing at least one organic silicon polymer.   2. The pressurizing uniform body according to claim 1, wherein a polyimide resin layer is formed on the high heat resistant resin layer to form a pressure surface.   The pressure-resisting uniform body according to claim 2, wherein the polyimide resin layer has a structure in which a large number of small-diameter cylinders are protruded and used as a pressing surface.   The pressurizing uniform body according to claim 1, wherein the hard substrate has a cavity, and the pressing surface is in the cavity.

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