Metal-based composite photoresist and application thereof in preparation of patterned metal layer of wafer and wafer bonding

Abstract

The invention provides a metal-based composite photoresist and application thereof in preparation of a patterned metal layer of a wafer and wafer bonding. The metal-based composite photoresist comprises a negative photoresist, a diluent, metal powder, an inorganic precursor, a dispersing agent and an auxiliary agent, the metal powder is metal powder with a double-peak particle size, the metal powder comprises large-particle metal powder and small-particle metal powder, and the inorganic precursor is selected from silane sol, borosilicate sol or aluminum salt. According to the method, the array pattern is formed by utilizing the double-peak characteristic of metal powder and combining a photoetching mask, so that the metal micro-column / micro-convex point structure prepared after sintering forms compressible support, and during bonding, the micro-columns / micro-convex points generate controlled plastic deformation under hot pressing to play a role in automatically compensating wafer warping and thickness errors; multi-point contact can be provided, and the effective bonding area is enlarged; and the inorganic precursor forms a buffer phase in situ after being sintered, so that metallurgical bonding can still be formed after compression.

Description

Technical Field

[0001] This invention relates to the field of photolithography materials technology, and in particular to a metal-based composite photoresist and its application in the preparation of patterned metal layers on wafers and wafer bonding. Background Technology

[0002] In the process of developing microelectronic devices towards high integration, high performance, and miniaturization, packaging and interconnect technology, as a key link, directly affects the reliability and performance of the devices. Metal materials, due to their excellent electrical and thermal conductivity and good mechanical properties, have become ideal interconnect materials in microelectronic packaging. Currently, the main methods for preparing patterned metal layers include electroplating, chemical plating, and physical vapor deposition, but these methods have many shortcomings: electroplating is complex, requires the preparation of a seed layer, and is prone to plating defects; chemical plating suffers from poor solution stability and serious environmental pollution; and physical vapor deposition produces relatively thin copper layers, making it difficult to meet the requirements for thick copper interconnects.

[0003] In recent years, researchers have begun to explore adding metal particles directly to photoresists to form metal-based photoresists, simplifying the fabrication process of patterned metal layers. Chinese patent CN114089599A discloses a photoresist composition based on metal nanoparticles, comprising metal nanoparticles, a photosensitizer, an anti-diffusion agent, and a photoresist solvent. Photolithographic patterns of different resolutions can be obtained through ultraviolet, electron beam, or extreme ultraviolet exposure. While existing photoresist technologies simplify the process of patterned metals, they still suffer from the following problems: uncontrollable sintering shrinkage and large pattern linewidth deviations; significant differences in the coefficients of thermal expansion between the sintered metal layer and the silicon / glass substrate, leading to easy delamination during bonding or thermal cycling; and the inability of planar metal patterns to compensate for warpage and thickness differences during wafer bonding, resulting in uneven bonding and interface voids.

[0004] Therefore, it is of great significance to develop a simple, low-cost method for preparing patterned metal layers with high-quality metal layers and excellent bonding effect, as well as a patterned wafer bonding process. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a metal-based composite photoresist and its application in the preparation of patterned metal layers on wafers and wafer bonding, so as to solve the problems of shrinkage after sintering of high metal-filled photoresists, the risk of interface failure between the metal layer and the substrate, and warping during wafer bonding in the prior art.

[0006] To achieve the above and other related objectives, the present invention provides the following technical solutions: In a first aspect, the present invention provides a metal-based composite photoresist comprising the following raw materials: negative photoresist, diluent, metal powder, inorganic precursor, dispersant, and additives.

[0007] Furthermore, the metal powder is a metal powder with a bimodal particle size, and the metal powder includes large-particle metal powder and small-particle metal powder; wherein the particle size of the large-particle metal powder is between 1 and 10 μm, and the particle size of the small-particle metal powder is between 50 and 200 nm; and the mass ratio of large-particle metal powder to small-particle metal powder is 60:40 to 90:10.

[0008] Furthermore, the metal powder includes one or more of the following: copper powder, tin powder, nickel powder, cobalt powder, iron powder, iron-based alloy powder, titanium-based alloy powder, or copper-based alloy powder.

[0009] Furthermore, the mass of the metal powder accounts for 30% to 80% of the mass of the negative photoresist.

[0010] By introducing metal powder with a bimodal particle size distribution and controlling the volume shrinkage and final pore structure during the sintering process through proportioning, it is possible to reduce pattern deformation and warping and stabilize the pattern; it is also possible to retain a limited number of closed pores as needed, reduce interfacial stress, and improve the buffering capacity of the bonding interface.

[0011] Furthermore, the inorganic precursor is selected from silane sol, borosilicate sol or aluminum salt, and the amount of the inorganic precursor is 1 to 10% of the mass of the metal powder.

[0012] By adding a small amount of inorganic precursor to the system, nanoscale glass or ceramic phases are formed in situ between metal particles during the debinding and sintering process. This can suppress grain boundary migration, improve morphological stability and electromigration reliability at high temperatures, and form an ultrathin stress buffer layer in situ between the metal layer and the substrate. This reduces the thermal expansion mismatch between the metal and silicon / glass, enhances interfacial bonding, reduces peeling during thermal cycling, reduces bonding residual stress, and improves reliability and lifespan.

[0013] Furthermore, the negative photoresist is selected from phenolic resin-type negative photoresist or epoxy resin-type negative photoresist.

[0014] Furthermore, the diluent is selected from at least one organic solvent such as acetone, propylene glycol methyl ether acetate (PGMEA), and N-methylpyrrolidone (NMP).

[0015] Furthermore, the amount of the diluent is 5-20% of the mass of the negative photoresist.

[0016] Furthermore, the dispersant includes one or more of the following: anionic surfactants, polyphosphates, silicates, silane coupling agents, polyacrylic acid or its salts, and polyacrylamide.

[0017] Furthermore, the mass of the dispersant accounts for 1 to 5% of the mass of the metal powder.

[0018] Furthermore, the additives include defoamers and leveling agents; wherein the mass of the defoamer accounts for 0.1% to 0.5% of the mass of the negative photoresist; and the mass of the leveling agent accounts for 0.1% to 2% of the mass of the negative photoresist.

[0019] Furthermore, the preparation method of metal-based composite photoresist includes: physically mixing negative photoresist, diluent, metal powder, inorganic precursor and dispersant in proportion, followed by mechanical stirring to initially achieve good dispersion of metal filler; then transferring to a ball mill jar for ball milling to further optimize the dispersion effect of metal filler and eliminate agglomeration; after ball milling, adding defoamer and leveling agent, and stirring at low speed to obtain a stable metal-based composite photoresist.

[0020] Furthermore, the ball milling process uses a quartz ball milling jar to disperse the metal-based composite photoresist; preferably, the ball milling speed is 300~500 r / min and the ball milling time is 1~6 h.

[0021] Furthermore, after adding defoamer and leveling agent, the stirring speed during low-speed stirring is 100~350rpm, and the stirring time is 5~10min.

[0022] A second aspect of the present invention provides a method for preparing a patterned metal layer on a wafer, comprising the following steps: S1. Pre-process the semiconductor wafer substrate; S2. Spin-coat the above-mentioned metal-based composite photoresist onto the wafer substrate to form a photoresist layer; S3. Use a photolithography machine and a mask to expose and develop the adhesive layer to prepare a patterned adhesive layer with an array of micropillars or microbumps. S4. Degrease and sinter the wafer substrate with the patterned adhesive layer to obtain a patterned metal layer with a compressible metal micropillar / microbump array structure.

[0023] Utilizing the bimodal characteristics of metal powder, the resulting metal micropillar / microbump structure forms a compressible support after sintering. During bonding, these micropillars / microbumps undergo controlled plastic deformation under hot pressing, automatically compensating for wafer warpage and thickness errors, and providing multi-point contact and expanding the effective bonding area. This improves the consistency and yield of large-area wafer bonding, reduces requirements for wafer warpage and flatness, and widens the process window. Furthermore, the inorganic precursor in the metal-based composite photoresist forms a buffer phase in situ after sintering, ensuring that metallurgical bonding can still be formed after compression.

[0024] A third aspect of the present invention provides a wafer bonding process with a patterned metal layer, comprising the following steps: S1. Pre-process the semiconductor wafer substrate; S2. Spin-coat the above-mentioned metal-based composite photoresist onto the wafer substrate to form a photoresist layer; S3. Use a photolithography machine and a mask to expose and develop the adhesive layer to prepare a patterned adhesive layer with an array of micropillars or microbumps. S4. Degrease and sinter the wafer substrate with the patterned adhesive layer to obtain a patterned metal layer with a compressible metal micropillar / microbump array structure. S5. In the wafer bonding machine, two wafer substrates with patterned metal layers are aligned, and then a hydrogen mixture is introduced for reduction treatment. After the reduction is completed, the two wafer substrates are bonded together. S6. In the vacuum environment of the bonding machine, the two wafer substrates bonded together are thermo-pressed and bonded.

[0025] In the bonding process, the reduction using a hydrogen-mixed gas effectively removes the metal oxide film; thermo-pressure diffusion bonding is performed in a vacuum environment, avoiding oxidation, resulting in a good bonding interface that meets the reliability requirements of microelectronic packaging. The entire process is low-cost and highly efficient, suitable for large-scale industrial production, and has broad application prospects in microelectronic device packaging, integrated circuit interconnection, and other fields.

[0026] In step S1, the pretreatment is to heat and dry the moisture, the temperature of the pretreatment is 100~150℃, and the pretreatment time is 5~15min.

[0027] In step S1, the wafer substrate is not specifically limited to any particular type. In step S2, the spin coating parameters are: front rotation speed 400~700 rpm, time 5~10s; rear rotation speed 850~2000 rpm, time 30~60s.

[0028] In step S2, the thickness of the adhesive layer is 5~50μm.

[0029] In step S3, the exposure time is 15-50 seconds, and the development time in the development process is 10-40 seconds.

[0030] In step S4, degreasing and sintering are carried out in a muffle furnace, and the degreasing and sintering atmosphere in the muffle furnace is a nitrogen atmosphere or a vacuum atmosphere.

[0031] In step S4, the degreasing stage is heated to 200~300℃ at a rate of 0.5~3℃ / min to remove organic components from the adhesive layer.

[0032] In step S4, the sintering stage is heated to 400~800℃ at a rate of 1~3℃ / min, so that the metal particles are further sintered and densified to form a patterned metal layer.

[0033] In step S4, the thickness of the patterned metal layer is 3~30μm.

[0034] In step S4, the patterned metal layer has a closed porosity of 1 to 15%.

[0035] In step S5, the alignment of the two wafer substrates is performed using a bonding alignment machine.

[0036] In step S5, the hydrogen mixture in the reduction process is either an argon-hydrogen mixture or a nitrogen-hydrogen mixture; the reduction temperature is 200~450℃, and the reduction time is 1~3h.

[0037] In step S5, reduction using a hydrogen mixture effectively removes the metal oxide film. In step S6, thermo-pressure diffusion bonding is performed in a vacuum environment to avoid oxidation, resulting in a good bonding interface that meets the reliability requirements of microelectronic packaging.

[0038] In step S6, the hot-press bonding temperature is 200~450℃, the bonding pressure is 0.05~0.4MPa, and the bonding time is 0.5~2h. After bonding is completed, the pressure is maintained and the temperature is lowered to room temperature before the bonded sheet is removed.

[0039] In step S6, the metal micropillar / microbump array structure undergoes 5-50% axial compression during the thermo-press bonding process.

[0040] As described above, the metal-based composite photoresist of the present invention and its application in wafer patterning metal layer preparation and wafer bonding have the following beneficial effects: 1. This invention uses metal powder with a bimodal particle size distribution. The reasonable ratio of large-particle metal powder to small-particle metal powder can reduce pattern deformation and warping, and stabilize the pattern. At the same time, it retains a limited number of closed pores, reduces interfacial stress, and improves the buffering capacity of the bonding interface.

[0041] 2. In the present invention, the inorganic precursor forms a nanoscale glass or ceramic phase between metal particles in situ during the debinding and sintering process, which effectively inhibits grain boundary migration, improves morphological stability and electromigration reliability at high temperature; at the same time, it forms an ultrathin stress buffer layer, reduces thermal expansion mismatch, and enhances interfacial bonding ability.

[0042] 3. The patterned metal layer preparation method of the present invention has a simple process, requiring no seed layer preparation; the patterning of the film layer can be directly achieved through photolithography and development. Compared with traditional processes that require additional sputtering / deposition buffer layers, the present invention eliminates the need for additional steps, reducing process complexity and cost.

[0043] 4. This invention utilizes the bimodal characteristics of metal powder, combined with the array pattern formed by a photolithographic mask, to create a compressible support structure for the metal micropillars / bumps after sintering. During bonding, these micropillars / bumps undergo controlled plastic deformation under hot pressing, automatically compensating for wafer warpage and thickness errors. This allows for macroscopic warpage >50μm, solving the problem of high surface flatness requirements for metal layers in traditional metal bonding processes. Simultaneously, these compressible micropillars / bumps provide multi-point contact and expand the effective bonding area, thereby improving the consistency and yield of large-area wafer bonding, lowering requirements for wafer warpage and flatness, and widening the process window. Furthermore, the inorganic precursor in the metal-based composite photoresist forms a buffer phase in situ after sintering, ensuring that metallurgical bonding can still be formed after compression.

[0044] 5. The sintering shrinkage rate of the patterned metal layer prepared by the metal-based composite photoresist of the present invention is significantly reduced, and the pattern linewidth and morphology are highly stable, which solves the problems of easy electroplating defects and poor stability of plating solution in traditional metal patterning preparation methods. Attached Figure Description

[0045] Figure 1 This is a photograph of the photoresist layer obtained after homogenizing copper-tin-based composite photoresist on a silicon substrate surface in Example 1 of the present invention.

[0046] Figure 2 The patterned copper-tin adhesive layer (a) obtained after exposure and development of the silicon substrate in Example 1 of the present invention; and the patterned copper adhesive layer (b) obtained after exposure and development of the glass substrate in Example 2.

[0047] Figure 3 The patterned copper-tin layer (a) obtained after degreasing and sintering of the silicon substrate in Example 1 of the present invention; and the patterned copper layer (b) obtained after degreasing and sintering of the glass substrate in Example 2.

[0048] Figure 4 This is a microscopic morphology image of the edge of the bonding layer pattern after hot-pressing bonding in Embodiment 2 of the present invention.

[0049] Figure 5 This is a photograph of the copper-copper bonded sheet after hot-press bonding in Embodiment 2 of the present invention. Detailed Implementation

[0050] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. It should be noted that, unless otherwise specified, the following embodiments and features described herein can be combined with each other.

[0051] Example 1 This embodiment provides a metal-based composite photoresist, comprising the following raw materials in parts by weight: 40 parts of phenolic resin-type negative photoresist, 6 parts of PGMEA diluent, 50 parts of metal powder (composed of 18.75 parts of copper powder and 31.25 parts of tin powder, wherein both copper powder and tin powder contain 60 wt% of large particles with D50=3μm and 40 wt% of small particles with D50=100nm), 2 parts of borosilicate sol precursor, 1.5 parts of ammonium polyacrylate dispersant, and 0.5 parts of additives (composed of defoamer and leveling agent in a 1:1 mass ratio).

[0052] This embodiment also provides a method for preparing the metal-based composite photoresist, including the following steps: (1) Add phenolic resin negative photoresist and PGMEA to a beaker in proportion and stir mechanically at 300 rpm for 10 min to make them fully mixed; (2) Then add metal powder, borosilicate sol precursor and ammonium polyacrylate dispersant to the above mixture, increase the stirring speed to 500 rpm and continue stirring for 30 min to initially disperse the metal powder in the colloid; (3) Transfer the preliminarily mixed slurry to a quartz ball mill jar and add quartz grinding balls (ball-to-material mass ratio of 5:1). Ball mill at 400 r / min for 6 h to further break up agglomerates and achieve uniform dispersion; (4) After ball milling, add defoamer and leveling agent, stir at 150 rpm for 5 min to obtain a stable copper-tin-based composite photoresist.

[0053] This embodiment also provides a wafer bonding process with a patterned metal layer, including the following steps: S1. Pre-processing of semiconductor wafer substrate: A 4-inch silicon wafer was used as the homogenizing substrate. The silicon wafer was placed on a hot plate to dry the moisture. The pretreatment temperature was 150℃ and the drying time was 10 minutes. S2, Spreading the coating: The copper-tin-based composite photoresist prepared above was coated onto the pretreated wafer using a spin coater. The spin coater was rotated at 500 rpm for 8 seconds before spin coatering and at 1500 rpm for 30 seconds after spin coatering. Finally, a uniform photoresist layer with a thickness of about 20 μm was formed on the wafer surface. S3, Exposure and Development: The photoresist layer was exposed using a lithography machine equipped with a 365nm (i-line) light source and a mask with a specific pattern. The light source power of the lithography machine was 16.2mW / cm2, and the exposure time was 30s. After exposure, the photoresist in the unexposed areas was developed using a 2.38% tetramethylammonium hydroxide (TMAH) solution for 30s. After development, the photoresist in the unexposed areas was removed, resulting in a copper-tin patterned photoresist layer consistent with the mask design. The copper-tin patterned photoresist layer has a regularly arranged array of metal composite micropillars, each with a diameter of 20μm and a spacing of 50μm. S4, Degreasing and Sintering: The developed wafer from step S3 is placed in a muffle furnace and heat-treated under a nitrogen atmosphere. Degreasing stage: The temperature is increased from room temperature to 350°C at a rate of 1°C / min and held for 60 minutes to completely decompose and remove organic components (resin, solvent, etc.) from the photoresist. Sintering stage: Continue heating at a rate of 2℃ / min to 600℃ and hold for 2 hours to allow solid-state sintering between copper and tin particles, forming a patterned metal layer with a compressible metal micropillar array structure. S5. Bonding alignment and de-alignment processing: Two wafers with corresponding patterned metal layers, processed as described above, are placed in a bonding alignment machine for precise alignment. Then, a nitrogen-hydrogen mixture (5% H2 volume fraction) is introduced into the bonding chamber. A reduction treatment is performed at 300°C for 2 hours to remove the oxide layer on the surface of the particles in the copper-tin film. After the reduction process is completed, the shims in the bonding machine are ejected to allow the two wafers to bond together. S6, Hot-press bonding: Vacuum the bonding machine, increase the temperature to 350°C, apply a bonding pressure of 0.1 MPa, and maintain the temperature and pressure for 2 hours. After bonding is completed, turn off the heating and slowly cool to room temperature (pressure holding and cooling). Then remove the bonding pressure and take out the bonded sheet.

[0054] in: Figure 1 The image shows the photoresist layer obtained after homogenizing copper-tin composite photoresist on a silicon substrate in Example 1. It can be seen that the copper-tin composite photoresist is stable, the metal filler is well dispersed, and the resulting photoresist layer has a smooth surface without bubbles. Figure 2 (a) is a photograph of the pattern after the copper-tin adhesive layer in the embodiment has been exposed and developed; Figure 3 (a) is a photograph of the patterned copper-tin layer after degreasing and sintering in a muffle furnace in the embodiment.

[0055] Example 2 This embodiment provides a metal-based composite photoresist, comprising the following raw materials in parts by weight: 40 parts of epoxy resin-type negative photoresist, 6 parts of NMP diluent, 50 parts of metal powder (copper powder, wherein the copper powder includes 80wt% of D50=3μm large particles and 20wt% of D50=100nm small particles), 2 parts of silane sol precursor, 1.5 parts of dispersant (silane coupling agent, KH570) and 0.5 parts of additive (composed of defoamer and leveling agent in a 1:1 mass ratio).

[0056] This embodiment also provides a method for preparing the metal-based composite photoresist, including the following steps: (1) Add epoxy resin negative photoresist and N-methylpyrrolidone (NMP) to a beaker in proportion and stir mechanically at 300 rpm for 15 min to make them fully mixed; (2) Then add copper powder, silane sol precursor and KH570 dispersant to the above mixture, increase the stirring speed to 500 rpm and continue stirring for 30 min to initially disperse the copper powder in the colloid; (3) Transfer the preliminarily mixed colloid to a quartz ball mill jar, add quartz grinding balls (ball-to-material mass ratio of 5:1), and ball mill at a speed of 400 r / min for 5 h to further break up agglomerates and disperse evenly; (4) After ball milling, add defoamer and leveling agent, stir at 150 rpm for 5 min to obtain a stable copper-based composite photoresist.

[0057] This embodiment also provides a wafer bonding process with a patterned metal layer, including the following steps: S1. Pre-processing of semiconductor wafer substrate: A 4-inch silicon wafer and a 4-inch BF33 glass sheet were used as the homogenizing substrates. The substrates were placed on a hot plate to dry the moisture. The pretreatment temperature was 150℃ and the drying time was 10min. S2, Spreading the coating: The copper-based composite photoresist prepared above was coated onto the pretreated wafer using a spin coater. The spin coater was rotated at 500 rpm for 8 seconds before spin coatering and at 1500 rpm for 30 seconds after spin coatering. Finally, a uniform photoresist layer with a thickness of about 20 μm was formed on the wafer surface. S3, Exposure and Development: The photoresist layer was exposed using a lithography machine equipped with a 365nm (i-line) light source and a mask with a specific pattern. The light source power of the lithography machine was 16.2mW / cm2, and the exposure time was 25s. After exposure, the photoresist was developed using a 2.38% tetramethylammonium hydroxide (TMAH) solution for 35s. After development, the photoresist in the unexposed areas was removed, resulting in a copper-based patterned photoresist layer consistent with the mask design. The copper-based patterned photoresist layer has a regularly arranged array of micropillars, each with a diameter of 20μm and a spacing of 50μm. S4, Degreasing and Sintering: The developed wafer from step S3 is placed in a muffle furnace and heat-treated under a nitrogen atmosphere. Degreasing stage: The temperature is increased from room temperature to 350°C at a rate of 2°C / min and held for 1 hour to completely decompose and remove organic components (resin, solvent, etc.) from the photoresist. Sintering stage: Continue heating at a rate of 2.5℃ / min to 600℃ and hold for 2 hours to allow solid-state sintering between copper and tin particles, forming a patterned metal layer with a compressible copper-based micropillar array structure. S5. Bonding alignment and de-alignment processing: The silicon wafer and BF33 glass substrate, which have undergone the above steps and have corresponding patterns, are placed in a bonding alignment machine for precise alignment. A nitrogen-hydrogen mixture (20% H2 volume fraction) is introduced into the bonding chamber. A reduction treatment is performed at 250°C for 2 hours to remove the oxide layer on the surface of the particles in the copper film layer. After the reduction process is completed, the shims in the bonding machine are ejected to allow the two wafers to be bonded together. S6, Hot-press bonding: Vacuum the bonding machine, increase the temperature to 450℃, apply a bonding pressure of 0.05MPa, and maintain the temperature and pressure for 1 hour. After bonding is completed, turn off the heating and slowly cool to room temperature (maintaining pressure and cooling down). Then remove the bonding pressure and take out the bonded sheet.

[0058] in: Figure 2 (b) is a photograph of the pattern on the copper paste layer on the BF33 glass substrate after exposure and development in this embodiment; Figure 3 (b) is a photograph of the copper paste layer on the BF33 glass substrate after degreasing and sintering in this embodiment; Figure 4 The microstructure of the bonded sheet in this embodiment shows that the bonded metal layer has a relatively dense structure. Figure 5 The image shows a copper-copper patterned bonding sheet after hot-press bonding in this embodiment (the substrate materials are silicon and glass, respectively). It can be seen that the pattern is well maintained after bonding.

[0059] In summary, this invention utilizes the bimodal characteristics of metal powder, combined with a photolithographic mask to form an array pattern, enabling the sintered metal micropillar / microbump structure to form a compressible support. During bonding, these micropillars / microbumps undergo controlled plastic deformation under hot pressing, automatically compensating for wafer warpage and thickness errors; they also provide multi-point contact and expand the effective bonding area; and the inorganic precursor forms a buffer phase in situ after sintering, ensuring that metallurgical bonding can still be formed after compression. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and has high industrial application value.

[0060] The terms used in this specification, such as "upper," "lower," "left," "right," "front," "back," "middle," and "one," are merely for clarity of description and are not intended to limit the scope of the invention. Any changes or adjustments to their relative relationships, without substantially altering the technical content, shall also be considered within the scope of the invention.

[0061] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. All equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this invention should still be covered by the claims of this invention.

Claims

1. A metal matrix composite photoresist, characterized by, The negative photoresist, a diluent, a metal powder, an inorganic precursor, a dispersant and an auxiliary agent are included. The metal powder is a metal powder with a bimodal particle size, and the metal powder includes large-particle metal powder and small-particle metal powder, the particle size of the large-particle metal powder is between 1 and 10 μm, and the particle size of the small-particle metal powder is between 50 and 200 nm. The inorganic precursor is selected from a silane sol, a borosilicate sol or an aluminum salt, and the amount of the inorganic precursor is 1-10% of the mass of the metal powder.

2. The metal matrix composite photoresist of claim 1, wherein The mass ratio of the large-particle metal powder to the small-particle metal powder is 60:40-90:

10.

3. The metal matrix composite photoresist of claim 1, wherein The metal powder includes one or more of copper powder, tin powder, nickel powder, cobalt powder, iron powder, iron-based alloy powder, titanium-based alloy powder or copper-based alloy powder, and the mass of the metal powder is 30-80% of the mass of the negative photoresist.

4. The metal matrix composite photoresist of claim 1, wherein The negative photoresist is selected from a phenolic resin type negative photoresist or an epoxy resin type negative photoresist.

5. The metal matrix composite photoresist of claim 1, wherein The auxiliary agent includes a defoaming agent and a leveling agent, the mass of the defoaming agent is 0.1-0.5% of the mass of the negative photoresist, and the mass of the leveling agent is 0.1-2% of the mass of the negative photoresist.

6. A method for preparing a patterned metal layer of a wafer, characterized in that, The method includes the following steps: S1, pretreating a semiconductor wafer substrate; S2, uniformly applying the metal-based composite photoresist on the wafer substrate to form a photoresist layer; S3, exposing and developing the photoresist layer using a photoetching machine and a mask to prepare a patterned photoresist layer with an array of micro-pillars or micro-bumps; S4, degreasing and sintering the wafer substrate with the patterned photoresist layer to obtain a patterned metal layer with a compressible array of micro-pillars / micro-bumps.

7. A wafer bonding process with a patterned metal layer, characterized in that, The method includes the following steps: S1, pretreating a semiconductor wafer substrate; S2, uniformly applying the metal-based composite photoresist on the wafer substrate to form a photoresist layer; S3, exposing and developing the photoresist layer using a photoetching machine and a mask to prepare a patterned photoresist layer with an array of micro-pillars or micro-bumps; S4, degreasing and sintering the wafer substrate with the patterned photoresist layer to obtain a patterned metal layer with a compressible array of micro-pillars / micro-bumps; S5, aligning two wafer substrates with the patterned metal layer in a wafer bonder, and then introducing a hydrogen mixture for reduction, and then bonding the two wafer substrates together after the reduction is completed; S6, hot-press bonding the two wafer substrates bonded together in a vacuum environment of the bonder.

8. The wafer bonding process of claim 7, wherein, In step S4, the patterned metal layer has a closed porosity of 1-15%.

9. The wafer bonding process of claim 7, wherein, In step S4, the thickness of the patterned metal layer is 3-30 μm.

10. The wafer bonding process of claim 7, wherein, In step S4, the temperature in the degreasing stage is raised to 200-300 °C at a rate of 0.5-3 °C / min, and the temperature in the sintering stage is raised to 400-800 °C at a rate of 1-3 °C / min.

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