Semiconductor bonding structure

Abstract

The invention relates to a semiconductor bonding structure. The semiconductor bonding structure mainly comprises a bearing substrate, a wafer and a foaming adhesive layer, the bearing substrate and the wafer are arranged in a stacked mode, and the foaming bonding layer is located between the bearing substrate and the wafer and used for bonding the bearing substrate and the wafer. The foaming adhesive layer comprises an adhesive body and a plurality of foaming particles, wherein the foaming particles can be decomposed and generate gas at high temperature. The gas generated by the foaming particles destroys the structure of the foaming bonding layer and pushes the bearing substrate and the wafer towards the two sides, so that a de-bonding step of the wafer and the bearing substrate is facilitated, and the wafer can be prevented from being damaged in the de-bonding process.

Description

TECHNICAL FIELD

[0001] The present application relates to a semiconductor bonding structure, which can reduce the probability of wafer damage during debonding. BACKGROUND

[0002] With the advancement of semiconductor technology, electronic products are currently developing towards the trend of being light, thin, short, high-performance, high-reliability, and intelligent. The wafer in the electronic product has an important influence on the performance of the electronic product. For example, a wafer with a thinner thickness can improve heat dissipation efficiency, increase mechanical properties, reduce on-resistance, reduce energy consumption, and reduce the volume and weight of the package.

[0003] Therefore, during the manufacturing of the wafer, the wafer is usually thinned by grinding to facilitate the reduction of the thickness of the wafer, the reduction of the on-resistance, the reduction of energy consumption, the acceleration of operation speed, and the extension of service life. However, the structure of the thinned wafer is very fragile and is prone to wafer warping or breaking in subsequent processes, thereby reducing the yield of the product.

[0004] In order to avoid the above problems, the wafer is usually bonded to a carrier substrate, and the thinned wafer is supported by the carrier substrate to avoid wafer warping or breaking during the process.

[0005] Specifically, a colloid can be coated on the surface of the carrier substrate and the wafer, and then the carrier substrate and the wafer are moved to a bonding machine for alignment, and the stacked wafer and carrier substrate are compressed by the compression unit and the stage of the bonding machine to complete the bonding of the wafer and the carrier substrate. After the bonding is completed, the wafer can be subjected to a grinding process, and then the wafer and the carrier substrate are debonded and separated.

[0006] The wafer has been thinned by grinding before debonding, so special care is needed during debonding. If the thinned wafer is improperly pushed or pulled, it may be damaged. SUMMARY

[0007] In order to solve the problems faced by the prior art, an object of the present application is to provide a semiconductor bonding structure, mainly comprising a carrier substrate, a wafer, and a foamed adhesive layer, wherein the foamed adhesive layer comprises an adhesive colloid and a plurality of foamed particles. The foamed particles form a positive zeta potential in the adhesive colloid, so that the foamed particles can be uniformly distributed in the adhesive colloid.

[0008] An object of the present application is to provide a semiconductor bonding structure, mainly comprising a carrier substrate, a wafer, an adhesive layer, and a foamed adhesive layer, wherein the adhesive layer is located on the surface of the carrier substrate, and the foamed adhesive layer is located between the adhesive layer and the wafer.

[0009] Specifically, the laminated adhesive layer and the foamed adhesive layer form a double-sided tape, wherein one surface of the double-sided tape is the adhesive layer and the other surface is the foamed adhesive layer. In use, the adhesive layer of the double-sided tape can be attached to a carrier substrate, and then a wafer is attached to the foamed adhesive layer of the double-sided tape, so that the wafer, the double-sided tape and the carrier substrate are laminated.

[0010] To achieve the above-mentioned purpose, the present application provides a semiconductor bonding structure, comprising: a carrier substrate; a wafer; and a foamed adhesive layer located between the carrier substrate and the wafer, and comprising an adhesive and a plurality of foamed particles, wherein the plurality of foamed particles decompose and generate gas at high temperature.

[0011] In at least one embodiment of the semiconductor bonding structure, the particle size of the plurality of foamed particles is between 10 microns and 50 microns.

[0012] In at least one embodiment of the semiconductor bonding structure, the weight percentage concentration of the plurality of foamed particles is between 20% and 50%.

[0013] In at least one embodiment of the semiconductor bonding structure, the plurality of foamed particles comprises a shell and a foamed material, and the shell is used to cover the foamed material.

[0014] In at least one embodiment of the semiconductor bonding structure, the pH value of the adhesive is less than or greater than the isoelectric point of the shell.

[0015] In at least one embodiment of the semiconductor bonding structure, the shell of the plurality of foamed particles is aluminum oxide.

[0016] In at least one embodiment of the semiconductor bonding structure, the foamed material comprises azo compounds, azoformamide, imino diacetic acid, azo dicarboxamide, organic carbonates or inorganic ammonium nitrate.

[0017] In at least one embodiment of the semiconductor bonding structure, an adhesive layer is located on the surface of the carrier substrate, and the adhesive layer is located between the foamed adhesive layer and the carrier substrate.

[0018] In at least one embodiment of the semiconductor bonding structure, the adhesive layer and the foamed adhesive layer are laminated to form a double-sided tape.

[0019] In at least one embodiment of the semiconductor bonding structure, the plurality of foamed particles comprises azo compounds, azoformamide, imino diacetic acid, azo dicarboxamide, organic carbonates or inorganic ammonium nitrate.

[0020] The semiconductor bonding structure of the present application mainly comprises a carrier substrate, a wafer and a foamed adhesive layer, wherein the foamed adhesive layer is used to bond the carrier substrate and the wafer. The foamed adhesive layer comprises an adhesive gel and a plurality of foamed particles, wherein the foamed particles will decompose and generate gas at high temperature.

[0021] The gas generated by the foamed particles can be used to destroy the structure of the foamed adhesive layer and push the carrier substrate and the wafer to both sides, so as to facilitate the unbonding process of the wafer and the carrier substrate and avoid damaging the wafer during the unbonding process. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 FIG. 1 is a cross-sectional view of an embodiment of the semiconductor bonding structure of the present application.

[0023] Figure 2 FIG. 2 is a cross-sectional view of an embodiment of the semiconductor bonding structure and the unbonding device of the present application.

[0024] Figure 3 FIG. 3 is a cross-sectional view of an embodiment of the foamed particles of the foamed adhesive layer of the present application.

[0025] Figure 4 FIG. 4 is a cross-sectional view of another embodiment of the semiconductor bonding structure of the present application.

[0026] BRIEF DESCRIPTION OF DRAWINGS 10: semiconductor bonding structure 11: carrier substrate 13: foamed adhesive layer 131: foamed particles 1311: shell 1313: foamed material 133: adhesive gel 15: wafer 20: unbonding device 21: first fixed plate 23: second fixed plate 30: semiconductor bonding structure 33: double-sided tape 331: adhesive layer X: first direction Y: second direction. DETAILED DESCRIPTION

[0027] Figure 1This is a cross-sectional schematic diagram of an embodiment of the semiconductor bonding structure of the present invention. As shown in the figure, the semiconductor bonding structure 10 mainly includes a carrier substrate 11, a foamed adhesive layer 13 and a wafer 15, wherein the foamed adhesive layer 13 is located between the carrier substrate 11 and the wafer 15 and is used to bond the carrier substrate 11 and the wafer 15.

[0028] During the wafer fabrication process, wafer 15 is typically thinned by grinding to reduce wafer thickness, lower on-resistance, reduce power consumption, increase processing speed, and extend lifespan. In different embodiments, wafer 15 may undergo back-side processing (e.g., back-side metallization or back-side power supply), dicing, or advanced packaging processes.

[0029] To prevent wafer 15 from breaking during the aforementioned process steps, it is typically bonded to the carrier substrate 11. In this embodiment of the invention, wafer 15 can be bonded to the carrier substrate 11 via a foamed adhesive layer 13, forming the semiconductor bonding structure 10 described in this invention.

[0030] Then, related processes can be performed on the wafer 15 of the semiconductor bonding structure 10, such as grinding and thinning, back-chip processing, dicing, or advanced packaging. After completing the above processes, the wafer 15 needs to be further separated from the carrier substrate 11, and subsequent processes can be performed on the wafer 15.

[0031] Since the thickness and structural strength of wafer 15 will be greatly reduced after grinding and thinning, if too much pressure is applied to wafer 15 during the separation of wafer 15 and substrate 11, wafer 15 may be damaged.

[0032] like Figure 2 As shown, during the separation of wafer 15 and carrier substrate 11, wafer 15, carrier substrate 11, and the colloid between them are typically heated to soften the colloid. Then, wafer 15 and carrier substrate 11 are fixed in place by the first fixing plate 21 and the second fixing plate 23 of the debonding device 20. For example, multiple adsorption holes can be provided on the surfaces of the first fixing plate 21 and the second fixing plate 23, and the negative pressure generated by the adsorption holes fixes wafer 15 and carrier substrate 11 onto the first fixing plate 21 and the second fixing plate 23, respectively.

[0033] The first fixing plate 21 can be displaced relative to the second fixing plate 23, and drive the wafer 15 and the carrier substrate 11 to be displaced relative to each other, so as to separate the wafer 15 and the carrier substrate 11. For example, the first fixing plate 21 can drive the wafer 15 to slide along a first direction X parallel to the surface of the carrier substrate 11, so as to separate the wafer 15 and the carrier substrate 11.

[0034] Although the above method can separate the wafer 15 and the carrier substrate 11, the softened adhesive will still provide a certain degree of adhesion between the wafer 15 and the carrier substrate 11. Therefore, when the first fixing plate 21 and the second fixing plate 23 move the wafer 15 relative to the carrier substrate 11, the softened adhesive will pull on the wafer 15 and the carrier substrate 11, which may cause damage to the wafer 15 during the separation process from the carrier substrate 11.

[0035] Furthermore, after the wafer 15 separates from the substrate 11, a significant amount of colloid typically remains on the surface of the wafer 15, requiring further removal of this residue. Generally, solvents such as isopropanol or acetone are used to remove the colloid residue. During the cleaning process, the wafer 15 is usually rotated, and solvent is sprayed onto its surface to completely remove the colloid residue. However, rotating the wafer 15 or spraying the solvent may cause damage to the wafer 15.

[0036] To avoid the possibility of wafer 15 breaking during the separation process from the carrier substrate 11, this invention further proposes to bond the wafer 15 and the carrier substrate 11 using a foamed adhesive layer 13. When the temperature exceeds a certain threshold, the structure of the foamed adhesive layer 13 will change to facilitate subsequent separation of the wafer 15 and the carrier substrate 11.

[0037] Specifically, such as Figure 1 As shown, the foamed adhesive layer 13 includes multiple foamed particles 131 and an adhesive colloid 133. The foamed particles 131 decompose and generate gas under high temperature conditions. The gas generated by the foamed particles 131 can be used to disrupt the structure of the adhesive colloid 133, thereby reducing the adhesive force of the foamed adhesive layer 13, and exerting pushing forces on the wafers 15 and the carrier substrate 11 on both sides of the foamed adhesive layer 13, thereby increasing the spacing between the wafers 15 and the carrier substrate 11, which is beneficial for subsequent separation of the wafers 15 and the carrier substrate 11.

[0038] In one embodiment of the present invention, the foamed particles 131 include organic azo compounds, azoformamide (C2H4O2N4), iminodiacetic acid (ADA), azodicarbonamide (ADC), organic carbonates, or inorganic ammonium nitrate (NH4NO3), wherein the particle size of the foamed particles 131 can be between 10 micrometers and 50 micrometers. The materials and particle sizes of the foamed particles 131 described above are merely one embodiment of the present invention and are not intended to limit the scope of the invention. Basically, any material that decomposes to produce gas under high-temperature conditions can be used to make the foamed particles 131.

[0039] In actual applications, the material of the foaming particles 131 can be selected according to the material of the adhesive gel 133 and the temperature of the subsequent process. Specifically, the foaming particles 131 made of organic azo compounds, azoformamide (C2H4O2N4), imino diacetic acid (ADA), or azodicarbonamide (ADC) have a decomposition temperature of about 180°C to 200°C, and produce carbon dioxide during the decomposition of the foaming particles 131. The foaming particles 131 made of organic carbonates have a decomposition temperature of about 200°C to 220°C, and produce carbon dioxide during the decomposition of the foaming particles 131. The foaming particles 131 made of inorganic ammonium nitrate (NH4NO3) have a decomposition temperature of about 250°C to 300°C, and produce helium and water vapor during the decomposition of the foaming particles 131. When the adhesive gel 133 is a high-temperature pyrolysis glue, the foaming particles 131 made of inorganic ammonium nitrate can be used.

[0040] In order to make the gas generated by the foaming particles 131 sufficient to destroy the structure of the adhesive gel 133, the proportion of the foaming particles 131 is usually greater than a certain degree. However, when the proportion of the foaming particles 131 is too large, it may affect the adhesion of the foaming adhesive layer 13, and may cause the wafer 15 to separate from the carrier substrate 11 during grinding, and cause damage to the wafer 15.

[0041] In an embodiment of the present application, the weight percentage concentration of the foaming particles 131 can be between 20% and 50%, so that the foaming adhesive layer 13 can provide sufficient adhesion and avoid separation of the wafer 15 from the carrier substrate 11 during subsequent processing. When the foaming adhesive layer 13 is heated to a temperature greater than the threshold value, the foaming particles 131 in the foaming adhesive layer 13 will generate sufficient gas to destroy the structure of the adhesive gel 133 and reduce the contact area between the foaming adhesive layer 13 and the wafer 15 and / or the carrier substrate 11. The proportion of the foaming particles 131 described above is only an embodiment of the present application, and is not a limitation of the scope of the present application. The material and adhesion of the adhesive gel 133 can affect the proportion of the foaming particles 131.

[0042] If the foaming particles 131 of the foaming adhesive layer 13 are uniformly distributed in the adhesive gel 133, the gas generated by the decomposition of the foaming particles 131 will uniformly destroy the overall structure of the foaming adhesive layer 13, and evenly apply a pushing force to the wafer 15 and the carrier substrate 11 on both sides of the foaming adhesive layer 13, which can effectively reduce the probability of damage to the wafer 15.

[0043] In practical applications, the zeta potential formed on the surface of multiple foam particles 131 can be used to make the multiple foam particles 131 uniformly distributed in the adhesive colloid 133. For example, the pH value of the adhesive colloid 133 can be greater than or less than the isoelectric point of the foam particles 131.

[0044] In one embodiment of the present invention, such as Figure 3 As shown, the foamed particle 131 may include a shell 1311 and at least one foamed material 1313, wherein the shell 1311 is used to cover the foamed material 1313. When the temperature of the foamed material 1313 exceeds a threshold value, the foamed material 1313 will generate gas. The gas generated by the foamed material 1313 will rupture the shell 1311 and can be used to destroy the structure of the foamed adhesive layer 13. For example, the shell 1311 may be aluminum oxide, while the foamed material 1313 may include organic azo compounds, azoformamide (C2H4O2N4), iminodiacetic acid (ADA), azodicarbonamide (ADC), organic carbonates, or inorganic ammonium nitrate (NH4NO3).

[0045] During manufacturing, the foamed material 1313 can be formed into multiple particles, and an aluminum oxide shell 1311 can be formed on the surface of the particles through atomic layer deposition. When the pH of the adhesive colloid 133 is within a specific range, the individual foamed particles 131 will repel each other, allowing the multiple foamed particles 131 to be evenly distributed and suspended within the adhesive colloid 133. For example, when the pH of the adhesive colloid 133 is less than or greater than the isoelectric point of the shell 1311, the shell 1311 on the surface of the foamed particles 131 can form a positive or negative boundary potential.

[0046] Specifically, the arrival potential of the foamed particles 131 is closely related to the pH value of the adhesive colloid 133, and its properties change with the pH value of the adhesive colloid 133. Taking the shell 1311 formed by aluminum oxide as an example, when the pH value of the adhesive colloid 133 is lower than the isoelectric point of aluminum oxide, the surface of the shell 1311 formed by aluminum oxide will be positively charged, making the arrival potential of the foamed particles 131 positive. The isoelectric point of aluminum oxide is approximately between pH 8 and pH 9.

[0047] When the pH of the adhesive colloid 133 is higher than the isoelectric point, the surface of the aluminum oxide shell 1311 will be negatively charged, making the boundary potential of the foamed particles 131 negative. When the pH of the adhesive colloid 133 is equal to the isoelectric point, the surface charge of the aluminum oxide shell 1311 is zero. At this time, the particles are the most unstable and are prone to aggregation and precipitation.

[0048] To this end, when the shell 1311 is aluminum oxide, the pH value of the adhesive gel 133 can be made lower than the isoelectric point of aluminum oxide, for example, less than pH 8, in which the plurality of foamed particles 131 forms a positive zeta potential and can be uniformly distributed and suspended in the adhesive gel 133.

[0049] In different embodiments, the pH value of the adhesive gel 133 can be made higher than the isoelectric point of aluminum oxide, for example, greater than pH 8, in which the plurality of foamed particles 131 forms a negative zeta potential and can be uniformly distributed and suspended in the adhesive gel 133. Basically, as long as the pH value of the adhesive gel 133 is not equal to the isoelectric point of the foamed particles 131, the foamed particles 131 can be prevented from gathering or precipitating.

[0050] In actual applications, the adhesive gel 133 with a proper pH value can be selected according to the material of the shell 1311 and the isoelectric point of the material. The shell 1311 being aluminum oxide is only one embodiment of the present application, and is not a limitation of the scope of the present application.

[0051] After the semiconductor bonding structure 10 completes the related processes, such as grinding and thinning, back-grinding, cutting, or advanced packaging, the semiconductor bonding structure 10 can be further heated, so that the plurality of foamed particles 131 in the foamed adhesive layer 13 decomposes and generates gas. The gas generated by the foamed particles 131 can be used to destroy the structure of the foamed adhesive layer 13, and push the wafers 15 and the carrier substrate 11 on both sides of the foamed adhesive layer 13, so that the wafers 15 and the carrier substrate 11 are separated.

[0052] Then the wafers 15 and the carrier substrate 11 can be fixed by the first fixing plate 21 and the second fixing plate 23 of the debonding device 20, respectively, in which the first fixing plate 21 can drive the wafers 15 to slide along the first direction X parallel to the surface of the carrier substrate 11, so as to separate the wafers 15 and the carrier substrate 11.

[0053] In different embodiments, the first fixing plate 21 can drive the wafers 15 to displace along the second direction Y perpendicular to the surface of the carrier substrate 11, so as to separate the wafers 15 and the carrier substrate 11.

[0054] By bonding the wafers 15 and the carrier substrate 11 through the foamed adhesive layer 13, not only the wafers 15 and the carrier substrate 11 can be separated, but also damage to the wafers 15 in the process of debonding can be avoided. Specifically, the decomposition and gas generation of the foamed particles 131 can be used to destroy the structure of the foamed adhesive layer 13, so as to reduce the adhesion between the foamed adhesive layer 13 and the wafers 15. In addition, the foamed adhesive layer 13 remaining on the surface of the wafers 15 can be reduced, which is conducive to the removal of the foamed adhesive layer 13 remaining on the surface of the wafers 15, and can avoid damage to the wafers 15 in the process of removing the foamed adhesive layer 13.

[0055] Figure 4 FIG. 4 is a cross-sectional view of another embodiment of the semiconductor bonding structure of the present application. As shown in the figure, the semiconductor bonding structure 30 mainly comprises a carrier substrate 11, a foamed adhesive layer 13, an adhesive layer 331 and a wafer 15, wherein the foamed adhesive layer 13 and the adhesive layer 331 are located between the carrier substrate 11 and the wafer 15 and used to bond the carrier substrate 11 and the wafer 15.

[0056] The materials and structures of the carrier substrate 11, the foamed adhesive layer 13 and the wafer 15 of the embodiment of the present application are the same as those of the embodiment shown in FIG. 3 and will not be repeated here. Figure 1

[0057] In this embodiment, an adhesive layer 331 is additionally provided between the foamed adhesive layer 13 and the carrier substrate 11, wherein the adhesive layer 331 can be a general adhesive. Specifically, the foamed adhesive layer 13 and the adhesive layer 331 are stacked and form a double-sided adhesive tape 33. In use, the adhesive layer 331 of the double-sided adhesive tape 33 can be pasted on the carrier substrate 11, and then the wafer 15 is pasted on the foamed adhesive layer 13 of the double-sided adhesive tape 33, so that the carrier substrate 11, the double-sided adhesive tape 33 and the wafer 15 are overlapped to form the semiconductor bonding structure 30.

[0058] In another embodiment of the present application, the adhesive layer 331 can be provided on the surface of the carrier substrate 11 by spraying or coating, and a plurality of foamed particles 131 and adhesive 133 are mixed in advance to form the foamed adhesive layer 13. The foamed adhesive layer 13 can be provided on the adhesive layer 331 by spraying or coating, and finally the wafer 15 is provided on the adhesive layer 331 to complete the bonding of the wafer 15 and the carrier substrate 11.

[0059] After the semiconductor bonding structure 30 completes the related processes, such as grinding and thinning, back-grinding, cutting or advanced packaging, the semiconductor bonding structure 30 can be further heated, so that the plurality of foamed particles 131 in the foamed adhesive layer 13 decompose and generate gas. The gas generated by the foamed particles 131 can destroy the structure of the adhesive 133 and push the wafer 15 and the adhesive layer 331 on both sides of the foamed adhesive layer 13, so that the wafer 15 is separated from the carrier substrate 11 on which the adhesive layer 331 is provided.

[0060] The above description is only a preferred embodiment of the present application and is not intended to limit the scope of the present application. Any equivalent changes and modifications made in accordance with the shape, structure, features and spirit of the present application described in the patent application range of the present application should be included in the patent application range of the present application.​

Claims

1. A semiconductor bonding structure, characterized in that, include: One substrate; One wafer; and A foamed adhesive layer is located between the carrier substrate and the wafer, and includes an adhesive colloid and a plurality of foamed particles, wherein the plurality of foamed particles decompose and generate gas at high temperature.

2. The semiconductor bonding structure as described in claim 1, characterized in that, The particle size of these multiple foamed particles ranges from 10 micrometers to 50 micrometers.

3. The semiconductor bonding structure as described in claim 1, characterized in that, The weight percentage concentration of the multiple foamed particles ranges from 20% to 50%.

4. The semiconductor bonding structure as described in claim 1, characterized in that, The plurality of foamed particles include a shell and a foamed material, the shell being used to encapsulate the foamed material.

5. The semiconductor bonding structure as described in claim 4, characterized in that, The pH of the adhesive is less than or greater than the isoelectric point of the shell.

6. The semiconductor bonding structure as described in claim 4, characterized in that, The shell of the multiple foamed particles is made of aluminum oxide.

7. The semiconductor bonding structure as described in claim 4, characterized in that, The foaming material includes organic azo compounds, azoformamide, iminodiacetic acid, azodicarbonamide, organic carbonates, or inorganic ammonium nitrate.

8. The semiconductor bonding structure as described in claim 1, characterized in that, It includes an adhesive layer located on the surface of the carrier substrate, and the adhesive layer is located between the foamed adhesive layer and the carrier substrate.

9. The semiconductor bonding structure as described in claim 8, characterized in that, The adhesive layer is layered with the foamed adhesive layer to form a double-sided tape.

10. The semiconductor bonding structure as described in claim 1, characterized in that, The multiple foamed particles include organic azo compounds, azoformamide, iminodiacetic acid, azodicarbonamide, organic carbonates, or inorganic ammonium nitrate.

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