A thermosetting liquid phase composition that can be used as a semiconductor substrate back grinding protective layer and its application

Abstract

The present invention discloses a thermosetting liquid-phase composition and its application for use as a protective layer for backgrinding semiconductor substrates, belonging to the field of semiconductor technology. The thermosetting liquid-phase composition comprises the following components by weight: 55 to 70 parts of EVA resin, 30 to 40 parts of a plasticizer, and 1 to 6 parts of an additive, wherein the additive is a thiazole compound. The temporary protective film formed using this thermosetting liquid-phase composition is resistant to the introduction of impurities, exhibits balanced adhesion, meets various requirements during wafer backgrinding, is easily peeled without residue, exhibits low shrinkage, exhibits stable and uniform overall properties, does not affect wafer quality, and is applicable to wafers of various sizes and materials.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and more particularly to a thermosetting liquid phase composition that can be used as a back grinding protective layer for a semiconductor substrate and applications thereof. Background Art

[0002] In the semiconductor manufacturing industry, wafer backgrinding is a critical step in the chip manufacturing process. As electronic devices continue to evolve towards thinner, more portable, and higher-performance devices, chips, as their core components, must be continuously optimized towards miniaturization and higher-end performance. This trend has driven the precision and quality of wafer backgrinding to unprecedented levels.

[0003] From a process perspective, wafer backgrinding aims to reduce wafer thickness, thereby facilitating the layout of more circuit components within the limited physical chip space. This significantly increases chip integration and optimizes chip performance across the board. During wafer backgrinding, the front side of the wafer is densely packed with intricate circuit structures. These circuits perform critical functions such as signal transmission and logical operations, and are fundamental to the proper functioning of the chip. Any minor damage to these circuits can lead to interrupted signal transmission within the chip, logical operation errors, and loss of chip functionality.

[0004] Since wafers are brittle, they are easily broken or scratched by grinding particles due to uneven force during the back grinding process. At the same time, the back grinding process must ensure that the microcircuits on the wafer surface are not damaged and the wafer surface flatness is excellent. Therefore, a wafer back grinding protective film is needed to protect the wafer to improve the back thinning efficiency and yield rate.

[0005] There are two main types of wafer backgrinding protective films available: wafer protection tape and wafer protection films based on PET or PVC. Because wafer protection tape is rolled, it's prone to wrinkling and has uneven adhesive thickness, making it difficult to fully adhere to the tiny structures on the wafer surface. This lacks protectiveness, and uneven viscosity can lead to adhesive residue and contamination of the wafer surface. Wafer protection films based on PET and PVC suffer from issues like excessive viscosity leading to adhesive residue, insufficient viscosity leading to warping, insufficient heat and chemical resistance, and excessive shrinkage, resulting in low yields and limiting their practical use.

[0006] In addition, the wafer backgrinding protective films on the market still have many problems. For example, it is difficult to completely cover the tiny structures on the wafer surface, and the protective film has a large shrinkage rate, which may cause damage to the microcircuit structure on the wafer surface and is difficult to peel off. Existing protective films cannot simultaneously meet the requirements of strong mechanical protection, good chemical protection, good high temperature resistance, and good flatness. Moreover, it is difficult to cure evenly when the film thickness is large. This makes the protective film's protective effect during the wafer back thinning process less comprehensive, and the protection effect varies from part to part, resulting in poor thinning effect and high defect rate. In addition, wafers of different sizes and materials have different requirements for the film structure and parameters. A single film cannot meet specific protection needs. Summary of the Invention

[0007] The purpose of the present invention is to overcome the above-mentioned defects of the prior art and provide a thermosetting liquid phase composition and its application that can be used as a back grinding protective layer for semiconductor substrates, which is not easy to introduce impurities, has a balanced bonding state, can meet various requirements during the wafer back grinding process, is easy to peel off without residue, and has a low shrinkage rate. The overall properties are stable and uniform, will not affect the quality of the wafer, and can be applied to wafers of various sizes and materials. The thermosetting liquid phase composition and multi-layer coating method.

[0008] To achieve the above object, the technical solution of the present invention is as follows:

[0009] A thermosetting liquid phase composition that can be used as a backgrinding protective layer for semiconductor substrates comprises the following components in parts by mass: 55 to 70 parts of EVA resin, 30 to 40 parts of plasticizer, and 1 to 6 parts of an additive; the additive is a thiazole compound.

[0010] Optionally, the structural formula of the thiazole compound is:

[0011] or .

[0012] Optionally, the thermosetting liquid composition comprises the following components in parts by mass: 60 to 68 parts of EVA resin, 32 to 38 parts of plasticizer, and 1 to 4 parts of additives.

[0013] Optionally, the plasticizer includes at least one of trioctyl trimellitate, sebacic acid polyester, and diisodecyl phthalate.

[0014] Optionally, the thermosetting liquid composition further comprises 0.5 to 10 parts by weight of an auxiliary agent.

[0015] Optionally, the auxiliary agent includes at least one of a leveling agent, a heat stabilizer, an antistatic agent, a defoaming agent, a viscosity stabilizer, a dispersant and a release agent.

[0016] The present invention also discloses an application of the thermosetting liquid phase composition as described above, which can be used as a semiconductor substrate back grinding protective layer, in a semiconductor backside thinning temporary protective film.

[0017] Optionally, the application method includes:

[0018] Mixing EVA resin, plasticizer and additives to obtain a thermosetting liquid composition;

[0019] The thermosetting liquid composition is coated on a molding die at a temperature of 130° C. to 180° C., and is cured by heating and pressurizing to form a temporary protective film.

[0020] Optionally, the application method includes:

[0021] After mixing the plasticizer, additives and auxiliary agents, the EVA resin is uniformly added to the obtained liquid mixture, and then uniformly dispersed using a high-speed stirrer at room temperature to obtain a thermosetting liquid composition;

[0022] The thermosetting liquid composition is coated on a molding die at a temperature of 130° C. to 180° C., and is cured by heating and pressurizing to form a temporary protective film.

[0023] Optionally, the temporary protective film has a thickness of 200 μm to 350 μm.

[0024] The implementation of the present invention will have the following beneficial effects:

[0025] The present invention provides a thermosetting liquid-phase composition that can be used as a protective film for wafer backgrinding. The composition contains EVA resin, a plasticizer, and additives. Leveraging the synergistic effects of these raw materials, it exhibits excellent fluidity and stable viscosity. It can flow onto complex substrate surfaces at high temperatures. After being applied to the wafer surface and cured, it forms a uniform, dense, smooth, and uniformly thick protective film. The film's thickness deviation is less than 10 μm, and optimally less than 5 μm. The excellent surface flatness significantly enhances wafer stability during backgrinding, ensures grinding uniformity, and improves chip yield.

[0026] The temporary protective film formed using this thermosetting liquid composition in this invention, with its unique physical and chemical properties, effectively buffers the mechanical impact generated during backgrinding, blocks the conduction of grinding heat to the front side of the wafer, and prevents abrasive particles from scratching and damaging the circuitry. This fully protects the chip's front-side precision circuitry and ensures its functional integrity. After curing, the film exhibits minimal shrinkage with the substrate, exhibits excellent wear resistance, and is resistant to deformation or damage during processing. When the protective film is removed after backgrinding, it leaves no surface residue and is easily peeled off mechanically at room temperature or thermally.

[0027] The adhesive force of the temporary protective film formed by the thermosetting liquid phase composition of the present invention can be confirmed by the peel strength specified in JIS 2107 based on 200um, and the peel strength of the formed film is preferably 0.1~2.0 kgf / inch, more preferably 0.2~0.8 kgf / inch. The composition only undergoes physical reaction, is in a single liquid form and a solvent-free form, is non-volatile at room temperature, has little change in physical properties, has good fluidity at high temperatures, is easy to use, can be precisely fitted to various complex wafer surfaces, is easy to store and transport, and has a wide range of applications. In addition, the protective film has a shrinkage rate of less than 0.1% after being placed at 25°C and a relative humidity of 85% for 12 hours, and a shrinkage rate of less than 0.05% under the conditions of heating and drying at 160°C for 30s, and can be used as a semiconductor substrate thinning protective agent. Compared with existing high-priced protective films, the present invention has low cost, excellent substrate protection performance, and can provide all-round protection for wafers. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The figure is a flow chart of the existing semiconductor backside thinning method.

[0029] Figure 2 This is a flow chart of the semiconductor backside thinning method of the present invention. DETAILED DESCRIPTION

[0030] The present invention will be further described below with reference to specific examples, but the present invention is not limited thereto in any way.

[0031] The invention discloses a thermosetting liquid phase composition that can be used as a back grinding protective layer for a semiconductor substrate. The composition comprises the following components in parts by mass: 55 to 70 parts of EVA resin, 30 to 40 parts of plasticizer, and 1 to 6 parts of an additive; the additive is a thiazole compound.

[0032] In one embodiment, the structural formula of the thiazole compound is:

[0033] or .

[0034] Specifically, the thiazole compound of the present invention can enhance the adhesion between the protective film and the semiconductor substrate through chemical bonding, and can reduce the stress concentration caused by the shrinkage of the protective film, thereby reducing the risk of warping or cracking of the substrate. The introduction of thiazole compounds can improve the mechanical properties and chemical stability of the protective film, not only providing good mechanical protection, but also maintaining performance under high temperature conditions. Thiazole compounds can reduce the shrinkage rate of the protective film by forming a stable cross-linked structure. In addition, by introducing specific functional groups such as hydroxyl or sulfonic acid groups, the cross-linking density and intermolecular forces of the protective film can be adjusted, thereby reducing the shrinkage rate and improving chemical stability, mechanical properties, thermal treatment performance and optimizing adhesion and easy peeling, which can effectively prevent the stress concentration caused by the shrinkage of the protective film during the thinning process of the wafer, thereby reducing the damage and deformation of the wafer.

[0035] In a specific embodiment, the thermosetting liquid composition includes the following components in parts by weight: 60 to 68 parts of EVA resin, 32 to 38 parts of plasticizer, and 1 to 4 parts of additives.

[0036] In a specific embodiment, the plasticizer includes at least one of trioctyl trimellitate, sebacic acid polyester, and diisodecyl phthalate.

[0037] In a specific embodiment, the thermosetting liquid composition further includes 0.5 to 10 parts by weight of an auxiliary agent.

[0038] In a specific embodiment, the additive includes at least one of a leveling agent, a heat stabilizer, an antistatic agent, a defoaming agent, a viscosity stabilizer, a dispersant, and a release agent. Specifically, the selection of the additive is relatively flexible and can be freely selected according to actual needs without much restriction.

[0039] In a specific embodiment, the leveling agent includes at least one of polyether silicone copolymer, silicone polyether copolymer, and modified acrylate; the thermal stabilizer includes at least one of octyl mercaptan tin, methyl vinyl polysiloxane, and epoxy soybean oil; the antistatic agent includes at least one of amide structure quaternary ammonium salt, stearic acid monoglyceride, and silicone-polyoxyethylene ether copolymer; the defoaming agent includes at least one of modified polyether silicone defoaming agent and polyoxyethylene polyoxypropylene ether; the dispersant includes at least one of silicone-polyether copolymer, polyether modified silicone dispersant, and ethylene bisstearamide; the viscosity stabilizer includes at least one of EVA wax, silane coupling agent, and fumed silica; and the release agent includes at least one of polydimethylsiloxane and perfluoropolyether.

[0040] like Figure 2 As shown, the present invention also discloses an application of the thermosetting liquid phase composition as described above that can be used as a back grinding protective layer for a semiconductor substrate in a temporary protective film for thinning the back side of a semiconductor.

[0041] In a specific embodiment, the method of application includes:

[0042] Mixing EVA resin, plasticizer and additives to obtain a thermosetting liquid composition;

[0043] The thermosetting liquid composition is applied to the molding die at 130°C to 180°C and cured by heating and pressurizing to form a temporary protective film.

[0044] In a specific embodiment, the method of application includes:

[0045] After mixing the plasticizer, additives and auxiliary agents, the EVA resin is uniformly added to the obtained liquid mixture, and then uniformly dispersed using a high-speed stirrer at room temperature to obtain a thermosetting liquid composition;

[0046] The thermosetting liquid composition is applied to the molding die at 130°C to 180°C and cured by heating and pressurizing to form a temporary protective film.

[0047] In a specific embodiment, the thickness of the temporary protective film is 200 μm-350 μm.

[0048] Specifically, since the thermosetting liquid composition used has good fluidity and stable viscosity, the protective film formed by curing has uniform thickness and good mechanical and physical and chemical properties, which can provide more comprehensive protection for the wafer.

[0049] Specifically, most of the existing methods are of the type of using tape lamination, circular cutting, and UV irradiation peeling, and the present invention optimizes the process flow. First, the tape lamination and circular cutting processes are refined into hot pressing and laminating. This innovation avoids the problems of low product qualification rate and complicated process flow caused by tape offset, insufficient cutting accuracy, poor edge quality and tape residue in traditional processes. In addition, the process of the present invention also refines UV irradiation peeling and film tearing into direct peeling of the protective film, eliminating the process of UV irradiation photolysis, avoiding potential problems such as uneven debonding and damage to the wafer due to UV exposure, reducing the defective rate, and making the protective film not only easy to peel off, but also more complete and stable separation from the wafer during peeling, ensuring the yield rate and quality stability of subsequent wafer processing.

[0050] Crucially, the present invention utilizes multi-layer coating technology, allowing the number of coating layers to be customized based on specific needs, including but not limited to coating using the liquid composition described herein. Compared to single-layer coatings, multi-layer coatings significantly enhance the protective film's physical and chemical protection properties. Furthermore, multi-layer coatings offer greater flexibility, allowing for adjustments in the number of coating layers and type of liquid composition to suit specific circumstances, extending their applicability to a wider range of applications.

[0051] The following are specific examples.

[0052] Example 1

[0053] 1. 65 parts of EVA resin, 35 parts of trioctyl trimellitate, and 2 parts of an additive (CAS: 23784-95-4) were uniformly mixed to form a thermosetting liquid composition. The structural formula of the additive is (CAS: 23784-95-4): .

[0054] 2. Take an appropriate amount of the thermosetting liquid composition according to actual needs and perform multi-layer lamination on the release film. The heat treatment temperature is 160°C and the pressure is 25 TONf / cm 2 , forming a temporary protective film with a thickness of 240 μm.

[0055] 3. After the last lamination is completed and decompression is completed, the release film is peeled off with air, and the edge of the formed protective film is removed with a blade to make it fit accurately with the substrate.

[0056] 4. Enter the post-polishing process.

[0057] Example 2

[0058] 1. After mixing trioctyl trimellitate, an additive (CAS: 172412-76-9), a leveling agent, a heat stabilizer, an antistatic agent, a defoamer, a dispersant, and a viscosity stabilizer, EVA resin is uniformly added to the resulting liquid mixture, and then uniformly dispersed using a high-speed stirrer at room temperature to obtain a thermosetting liquid composition, wherein the thermosetting liquid composition comprises the following components in parts by weight: 65 parts of EVA resin, 35 parts of trioctyl trimellitate, 2 parts of the additive, 1.5 parts of a leveling agent (polyether siloxane copolymer), 3 parts of a heat stabilizer (epoxidized soybean oil), 0.5 parts of an antistatic agent (monoglyceride of stearate), 1.5 parts of a defoamer (polyoxyethylene polyoxypropylene ether), 1.5 parts of a dispersant (siloxane-polyether copolymer), and 1 part of a viscosity stabilizer (EVA wax); wherein the structural formula of the additive is (CAS: 172412-76-9): .

[0059] 2. Take an appropriate amount of the liquid composition according to actual needs and perform multi-layer lamination on the release film. The heat treatment temperature is 160°C and the pressure is 25 TONf / cm 2 , forming a temporary protective film with a thickness of 240 μm;

[0060] 3. After the last lamination is completed and the pressure is released, the release film is peeled off with air, and the edge of the formed protective film is removed with a blade to make it fit accurately with the substrate;

[0061] 4. Enter the post-polishing process.

[0062] Example 3

[0063] The only difference between Example 3 and Example 1 is that the thermosetting liquid composition includes the following components in parts by mass: 55 parts of EVA resin, 30 parts of trioctyl trimellitate, and 1 part of additives.

[0064] Example 4

[0065] The only difference between Example 4 and Example 1 is that the thermosetting liquid composition includes the following components in parts by mass: 70 parts of EVA resin, 40 parts of trioctyl trimellitate, and 6 parts of additives.

[0066] Comparative Example 1

[0067] Comparative Example 1 is compared with Example 1, except that Comparative Example 1 does not contain any additive.

[0068] Comparative Example 2

[0069] Comparative Example 2 is compared with Example 2, except that Comparative Example 2 does not contain any additive.

[0070] Comparative Example 3

[0071] The only difference between Comparative Example 3 and Example 1 is that the mass fraction of the additive in the composition in Comparative Example 3 is 8 parts.

[0072] Comparative Example 4

[0073] The only difference between Comparative Example 4 and Example 1 is that the mass fraction of the additive in the composition in Comparative Example 4 is 0.5 parts.

[0074] Comparative Example 5

[0075] The only difference between Comparative Example 5 and Example 2 is that the mass fraction of the additive in the composition in Comparative Example 5 is 8 parts.

[0076] Comparative Example 6

[0077] The only difference between Comparative Example 6 and Example 2 is that the mass fraction of the additive in the composition in Comparative Example 6 is 0.5 parts.

[0078] Comparative Example 7

[0079] This comparative example uses the existing conventional PET wafer back grinding protective tape.

[0080] Comparative Example 8

[0081] This comparative example uses a wafer protective film with PET and PVC as main materials.

[0082] Comparative Example 9

[0083] The only difference between this comparative example and Example 2 is that the thickness of the temporary protective film is 360 μm.

[0084] Test Case

[0085] The wafers obtained in Examples 1-4 and Comparative Examples 1-9 were subjected to performance tests, and the results are shown in Table 1. In the "Post-stripping residue" column, "o" indicates no residue, and "x" indicates residue. In the "Whether bubbles are generated" column, "o" indicates no bubbles, and "x" indicates bubbles are generated.

[0086] Table 1 Performance test results of wafers obtained from Examples 1-4 and Comparative Examples 1-9

[0087]

[0088] As shown in Table 1, the thermosetting liquid composition of the present invention has good fluidity on the surface of the wafer, can form a uniform and continuous film layer on the surface of the wafer, and is not easy to produce bubbles after solidification. After the wafer back grinding process is completed, the peeling strength required for peeling the temporary protective film formed by the present invention is relatively small, and there is no need to adopt UV peeling or chemical peeling methods. It can be directly peeled off without any treatment, the operation is relatively simple, and there is no residue after peeling, and there is no need to add a complicated cleaning process. In addition, the temporary protective film of the present invention has a small shrinkage rate and good dimensional stability, and will not cause damage to the microstructure on the surface of the wafer due to the large shrinkage rate; the peel strength retention rate is high, and it will not be corroded or failed due to the grinding fluid, and the chemical stability is high. Compared with the comparative example, the temporary protective film formed using the thermosetting liquid composition of the present invention can grind the wafer to a thinner thickness, and the TTV is also significantly reduced, so it can be used to manufacture chips with smaller size and better performance.

[0089] In summary, the thermosetting liquid composition for wafer backgrinding protection of the present invention is simpler to operate than existing products and offers significantly improved performance compared to PET wafer backgrinding protection tape and wafer protection films primarily made of PET and PVC. Furthermore, the present invention utilizes multi-layer lamination technology, significantly enhancing the protective film's physical and chemical protection properties, broadening its application range.

[0090] The above-described embodiments merely represent several implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A thermosetting liquid phase composition that can be used as a back grinding protective layer for a semiconductor substrate, characterized in that: The composition includes the following parts by weight: 55 to 70 parts of EVA resin, 30 to 40 parts of plasticizer and 1 to 6 parts of additives; The additive is a thiazole compound; The structural formula of the thiazole compound is: or .

2. The thermosetting liquid phase composition that can be used as a back grinding protective layer for semiconductor substrates according to claim 1, characterized in that: The thermosetting liquid phase composition comprises the following components in parts by mass: 60 to 68 parts of EVA resin, 32 to 38 parts of plasticizer, and 1 to 4 parts of additives.

3. The thermosetting liquid phase composition that can be used as a back grinding protective layer for semiconductor substrates according to claim 1, characterized in that: The plasticizer includes at least one of trioctyl trimellitate, sebacic acid polyester, and diisodecyl phthalate.

4. The thermosetting liquid phase composition used as a semiconductor substrate back grinding protection layer according to claim 1, characterized in that: The thermosetting liquid phase composition further comprises an auxiliary agent in an amount of 0.5 to 10 parts by weight; The auxiliary agent includes at least one of a leveling agent, a heat stabilizer, an antistatic agent, a defoaming agent, a viscosity stabilizer, a dispersant and a release agent.

5. Use of the thermosetting liquid phase composition as claimed in any one of claims 1 to 4 as a semiconductor substrate back grinding protective layer in a semiconductor back thinning temporary protective film.

6. The use according to claim 5, characterized in that The method of application includes: Mixing EVA resin, plasticizer and additives to obtain a thermosetting liquid composition; The thermosetting liquid composition is coated on a molding die at a temperature of 130° C. to 180° C., and is cured by heating and pressurizing to form a temporary protective film.

7. The use according to claim 5, characterized in that The method of application includes: After mixing the plasticizer, additives and auxiliary agents, the EVA resin is uniformly added to the obtained liquid mixture, and then uniformly dispersed using a high-speed stirrer at room temperature to obtain a thermosetting liquid composition; The thermosetting liquid composition is coated on a molding die at a temperature of 130° C. to 180° C., and is cured by heating and pressurizing to form a temporary protective film.

8. The use according to claim 6 or 7, characterized in that The thickness of the temporary protective film is 200 μm to 350 μm.

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