Semiconductor encapsulation ultra-low pressure filling rubber and preparation method thereof

Abstract

This invention relates to the field of semiconductor packaging technology, and more particularly to an ultra-low pressure filling lubricating rubber for semiconductor packaging and its preparation method. The raw materials for preparing the lubricating rubber include: uncured rubber, filler, ultra-low pressure filling lubricating agent, and vulcanizing agent; the amount of ultra-low pressure filling lubricating agent added is 5-9 wt% of the total mass of the lubricating rubber; the uncured rubber includes EPDM rubber and cis-butadiene rubber; the ultra-low pressure filling lubricating agent includes at least one of oxidized modified polyolefin synthetic waxes and phenyl modified organosiloxanes; the mold closing pressure of the lubricating rubber is below 30t. By introducing a specific amount of ultra-low pressure filling lubricating agent into the rubber system, the rheological properties and interfacial characteristics of the rubber are effectively improved, enabling it to maintain excellent flowability and adhesion under ultra-low pressure conditions, thus meeting the requirements of refined, low-stress semiconductor packaging processes.

Description

Technical Field

[0001] This invention relates to the field of semiconductor packaging technology, and in particular to an ultra-low pressure filling lubricating rubber for semiconductor packaging and its preparation method. Background Technology

[0002] In the semiconductor packaging process, the complete and thorough filling of the mold cavity with lubricating rubber is a core technological condition for ensuring the molding quality of semiconductor packaged products and improving the stability and efficiency of mass production. In the existing semiconductor packaging industry production system, in addition to conventional 40t~130t atmospheric pressure and 130t~160t high-pressure packaging equipment, a large number of ultra-low pressure packaging presses are still in actual production applications. These machines generally have a closing pressure below 30t, and their pressure output upper limit is far lower than that of traditional atmospheric and high-pressure packaging equipment, forming a differentiated ultra-low pressure packaging operating condition system. As a key functional material for cleaning, lubricating, and filling gaps in packaging molds, the compatibility of lubricating rubber directly determines the yield rate and process feasibility of ultra-low pressure packaging. Therefore, matching lubricating rubber materials with specialized properties to the special operating conditions of ultra-low pressure packaging has become an important direction for process optimization in the industry.

[0003] Currently, conventional lubricating rubber materials in the industry cannot adapt to the operating conditions of ultra-low pressure encapsulation processes, exhibiting significant technical defects and process shortcomings. On the one hand, traditional lubricating rubbers are developed based on normal pressure and high pressure encapsulation conditions. The rigidity, flowability, and flexibility of the materials cannot adapt to the limited pressure output of ultra-low pressure equipment. Under low-pressure mold closing conditions, it is difficult to achieve full adhesion to the mold and complete filling of the fine gaps in the mold, directly resulting in substandard mold cleaning and lubrication effects. On the other hand, existing lubricating rubbers generally suffer from poor synergy between filling and lubrication performance, with prominent performance mismatches: low-hardness lubricating rubbers, while possessing good mold fit and gap filling capabilities, have weak lubrication performance and are prone to sticking to the inner wall of the mold after molding, causing problems such as product demolding difficulties and mold contamination; while high-lubrication lubricating rubbers are mostly hard, with significantly reduced flexibility, making it difficult to penetrate into the fine gaps in the mold and unable to achieve comprehensive filling and cleaning, ultimately resulting in poor overall mold cleaning and lubrication consistency and insufficient process stability.

[0004] In summary, the current lack of a dedicated lubricating rubber that can balance low pressure, high flexibility, fine gap filling, and excellent mold lubrication makes it difficult to meet the production requirements of ultra-low voltage semiconductor packaging processes. This has become a key technical challenge restricting the popularization and improvement of ultra-low voltage packaging processes. Summary of the Invention

[0005] To address the shortcomings of existing semiconductor packaging processes, such as insufficient fluidity of traditional lubricating rubbers under ultra-low pressure conditions, difficulty in achieving seamless filling of complex cavities, and the inability to coordinate filling performance with lubrication effects, this invention aims to overcome these deficiencies by providing an ultra-low pressure filling lubricating rubber for semiconductor packaging. By introducing a specific amount of ultra-low pressure filling lubricating agent into the rubber system, the rheological properties and interfacial characteristics of the rubber are effectively improved, enabling it to maintain excellent fluidity and adhesion under ultra-low pressure conditions. This allows for seamless filling of complex mold cavities while simultaneously forming a uniform and stable lubricating layer on the mold, providing efficient lubrication and protection, and meeting the requirements of refined, low-stress semiconductor packaging processes.

[0006] The first aspect of the present invention provides an ultra-low pressure filling lubricating rubber for semiconductor packaging, wherein the raw materials for preparing the lubricating rubber include: uncured rubber, filler, ultra-low pressure filling lubricating agent, and vulcanizing agent.

[0007] Optionally, the mold closing pressure of the lubricating rubber is below 30t; more preferably, it is below 20t.

[0008] The lubricating rubber involved in this invention is a functional rubber auxiliary material used on the surface of molds in semiconductor packaging processes. By forming a uniform lubricating layer on the inner wall of the mold, it achieves isolation between the encapsulating resin and the mold, demolding, and cavity filling. It also has the functions of demolding lubrication, cavity venting, and gap filling, which can reduce mold closing resistance, reduce mold sticking defects, and improve packaging yield and production efficiency. Traditional lubricating rubber can be used stably under normal mold closing pressure (generally 40~160t), but under low pressure or ultra-low pressure conditions, it is often difficult to adapt to process requirements due to insufficient flexibility and filling capacity.

[0009] The clamping pressure involved in this invention refers to the total clamping force applied by the clamping mechanism to the upper and lower molds during the semiconductor packaging press's packaging process, acting on the lubricating rubber and packaging material inside the mold cavity, wherein the corresponding effective mold area is 980~1020 cm². 2 This pressure, provided by the press drive system, is a key process parameter that determines the fluidity, filling capacity, and molding effect of the lubricating rubber.

[0010] In some embodiments, the raw materials for preparing the lubricating rubber, by weight, include: 20-70 parts of uncured rubber, 10-40 parts of filler, 5-9 parts of ultra-low pressure filling lubricating agent, and 0.5-3 parts of vulcanizing agent.

[0011] The uncured rubber may include EPDM rubber, butadiene rubber, isoprene rubber, styrene-butadiene rubber, etc.

[0012] Optionally, the uncured rubber includes one or more combinations of EPDM rubber, butadiene rubber, and isoprene rubber.

[0013] Further optionally, the uncured rubber includes ethylene propylene diene monomer (EPDM) rubber and butadiene rubber; the mass ratio of EPDM rubber to butadiene rubber is (1.5-4):1, for example 1.5:1, 2:1, 3:1, 4:1, etc.; further optionally, it is 2:1.

[0014] The uncured rubber involved in this invention refers to rubber raw materials that have not yet undergone vulcanization and crosslinking reactions, also known as raw rubber. Its molecular structure is mainly linear or has a small number of branched macromolecular chains, and it has not formed a three-dimensional network structure. Therefore, it has good plasticity, flowability and mixing and processing performance, and can undergo crosslinking reactions through heating or radiation in the presence of vulcanizing agents, additives, etc., to form vulcanized rubber with elasticity and mechanical strength.

[0015] The ultra-low pressure filling and lubricating agents can include hydrophobically modified nano-inorganic powders, oxidically modified polyolefin synthetic waxes, fluorinated organosiloxanes, phenyl modified organosiloxanes, etc.

[0016] Optionally, the amount of the ultra-low pressure filling and lubrication agent added is 5-9 wt% of the total mass of the lubrication rubber; examples include 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, etc. Within this range, the agent can be uniformly dispersed in the rubber matrix, ensuring both the excellent flexibility and fine gap filling ability of the rubber under ultra-low pressure (<30t) encapsulation conditions, and providing a continuous and stable demolding lubrication effect, thus achieving a synergistic balance between filling performance and lubrication performance.

[0017] The ultra-low pressure filling and lubricating agents can include hydrophobically modified nano-inorganic powders, oxidically modified polyolefin synthetic waxes, phenyl modified organosiloxanes, etc.

[0018] Optionally, the ultra-low pressure filling and molding aid includes at least one of oxidized modified polyolefin synthetic waxes and phenyl modified organosiloxanes.

[0019] Further optionally, the ultra-low pressure filling and molding aid includes oxidized modified polyolefin synthetic waxes and phenyl modified organosiloxanes; the mass ratio of the oxidized modified polyolefin synthetic waxes to the phenyl modified organosiloxanes is 1:(0.5-3); examples include 1:0.5, 1:1, 1:2, 1:3, etc.

[0020] The oxidatively modified polyolefin synthetic waxes may include oxidatively modified polyethylene waxes, oxidatively modified polypropylene waxes, etc.; further, oxidatively modified polypropylene waxes may be selected.

[0021] The phenyl-modified organosiloxanes may include vinyl-terminated polyphenylsiloxanes, hydrogen-containing phenyl polysiloxanes, hydroxyl-terminated polyphenylsiloxanes, methylphenyl polysiloxanes, etc.; further, they may be vinyl-terminated polyphenylsiloxanes.

[0022] Most preferably, the ultra-low pressure filling and lubricating agent comprises an oxidized modified polypropylene wax and a vinyl-terminated polyphenylsiloxane in a mass ratio of 1:1.

[0023] To address the issues of insufficient flowability and filling capacity of traditional lubricating rubbers under ultra-low pressure conditions in semiconductor packaging, which prevent complete filling of fine gaps in the mold and make it difficult to balance filling and lubrication performance, leading to sticking and demolding difficulties, this invention incorporates an ultra-low pressure filling lubricating agent into the lubricating rubber system. This agent is selected from at least one of hydrophobic modified nano-inorganic powders, oxidized modified polyolefin synthetic waxes, and phenyl modified organosiloxane compounds. Using this technical solution, the lubricating rubber of this invention can achieve complete filling of complex mold cavities and micron-level fine gaps under ultra-low pressure conditions of less than 30t, while also possessing excellent lubrication and demolding capabilities, effectively avoiding mold sticking problems. The main reason is that the above-mentioned additives can be uniformly dispersed in the rubber matrix, effectively improving the overall rheological properties of the rubber, enhancing the material's flexibility and spreading fluidity, and reducing the material's filling resistance. At the same time, the additives can form a uniform lubricating layer on the surface of the rubber after molding, which significantly improves the interface lubrication effect while ensuring the rubber's flexible filling and bonding ability. Ultimately, this achieves synergistic optimization of filling performance and lubrication performance, meeting the application requirements of semiconductor ultra-low voltage packaging processes.

[0024] The fillers may include silica, zinc barium white, quartz sand, talc, kaolin, titanium dioxide, silica fume, calcium carbonate, etc.

[0025] Optionally, the filler includes one or more of the following: silica, zinc barium white, quartz sand, talc, kaolin, and titanium dioxide.

[0026] Further optionally, the filler includes kaolin and silica, wherein the mass ratio of kaolin to silica is (1-3):1; examples include 1:1, 2:1, 3:1, etc.

[0027] Further optionally, the silica includes precipitated silica.

[0028] The precipitated silica involved in this invention is different from fumed silica. It is a hydrated silica powder prepared by liquid-phase precipitation process. Its surface contains a large number of silanol groups, which can improve the mechanical strength and structural stability of the vulcanized rubber and meet the performance requirements of rubber auxiliaries in semiconductor packaging processes.

[0029] The vulcanizing agents may include peroxide vulcanizing agents, sulfur vulcanizing agents, metal oxide vulcanizing agents, etc.

[0030] Examples of peroxide-based vulcanizing agents include dicumyl peroxide (DCP), bis(2,5-dimethyl-2,5-di(tert-butylperoxy)hexane), and di-tert-butylperoxide (BIPB).

[0031] Examples of sulfur-based vulcanizing agents include sulfur (S) and organic sulfur-containing compounds (such as thiuram-based TMTDs). Examples of metal oxide sulfiding agents include zinc oxide (ZnO), magnesium oxide (MgO), and lead monoxide (PbO).

[0032] The vulcanizing agent includes at least one of peroxide vulcanizing agents and sulfur vulcanizing agents; it is further optionally a peroxide vulcanizing agent; and most preferably DCP.

[0033] A second aspect of the present invention provides a method for preparing an ultra-low pressure filling lubricating rubber for semiconductor packaging, wherein the preparation steps of the lubricating rubber include: The filler and vulcanizing agent are mixed evenly to obtain a premix; Uncured rubber is mixed at 50-70℃ for 1-5 minutes, then premixed in batches and mixed at 80-95℃ for 5-15 minutes; then ultra-low pressure filler and mold lubricant are added at below 90℃ and mixed for 2-10 minutes to obtain the mixed material. Cool the mortar to obtain a lubricated rubber.

[0034] This invention employs a segmented internal mixing process to prepare the ultra-low pressure filled lubricating rubber. By optimizing the feeding sequence, temperature range, and mixing time, uniform dispersion of each component in the rubber matrix is ​​achieved. This process first performs low-temperature plasticizing on the uncured rubber to reduce viscosity, then adds filler and vulcanizing agent premixes in batches, and finally adds lubricating agent. This avoids both vulcanizing agent scorching and lubricating agent decomposition and inactivation, effectively ensuring the performance stability and batch consistency of the rubber material.

[0035] Optionally, the premixed material is added in three batches, with each batch requiring a mixing time of 3-5 minutes.

[0036] Optionally, the mixing method is high-speed mixing, for example, mixing evenly at a speed of 1500-3000 rpm.

[0037] The third aspect of the present invention provides a method for using ultra-low pressure filling lubricating rubber for semiconductor packaging, wherein the temperature of the lubricating rubber during the lubrication operation is 150-190°C and the mold closing pressure is 10-30t.

[0038] Optionally, the method of using the lubricating rubber specifically includes: The lubricating rubber is placed inside the mold cavity of the semiconductor packaging mold; Molding (i.e., mold lubrication treatment) is carried out at a target temperature of 150-190℃ and a mold closing pressure of 10-30t. After molding, remove the lubricating rubber. The mold after lubrication can be directly sealed. Repeat the above steps for lubrication every 200-500 molding cycles.

[0039] In some implementations, if a small amount of lubricating rubber adheres to the mold surface, it can be cleaned by blowing it away with an air gun.

[0040] The ultra-low pressure filling and lubrication rubber of this invention can still achieve excellent filling and lubrication effects under mold closing pressure conditions of 150-190℃ and 10-30t. In conventional lubrication processes, lower mold closing pressure makes it difficult to drive the rubber to flow fully and conform to the complex cavity of the mold, which easily leads to problems such as dead corners in filling and insufficient adhesion. At the same time, the rubber has insufficient wettability on the mold surface under low pressure, making it difficult to form a uniform and continuous lubrication layer, resulting in defects such as difficulty in demolding and mold damage. This invention significantly improves the rheological properties of rubber under low temperature and low pressure by introducing a specific ultra-low pressure filling lubricant. This allows the rubber to maintain good fluidity and spreadability under limited pressure, enabling it to spontaneously wet and penetrate into the micron-level gaps, deep pores, and complex cavity structures of the mold without high-pressure extrusion under ultra-low pressure conditions, achieving all-round, dead-angle-free adhesion to the inner wall of the mold. At the same time, the lubricant can uniformly migrate to the contact interface between the rubber and the mold during the molding process, forming a stable, low-friction lubricating layer. This effectively lubricates the mold under low pressure conditions, while achieving excellent cavity filling effect and long-lasting lubrication and demolding ability, thus solving the limitation of traditional lubricating rubbers being unable to adapt to ultra-low pressure encapsulation processes.

[0041] Beneficial effects: This invention provides an ultra-low pressure filling lubricating rubber for semiconductor packaging and its preparation method, which has the following advantages: (1) This invention provides an ultra-low pressure filling lubricating rubber for semiconductor packaging. By introducing an ultra-low pressure filling lubricating agent, it effectively solves the problems of insufficient fluidity and poor filling ability of traditional lubricating rubber under low pressure conditions. It can achieve complete fitting of complex mold cavities in ultra-low pressure packaging processes with mold closing pressure as low as 30t, and is suitable for low stress and fine production requirements. (2) The ultra-low pressure filling and lubrication agent of the present invention is selected from at least one of oxidized modified polyolefin synthetic waxes and phenyl modified organosiloxanes, and the addition amount is controlled to be 5-9 wt% of the total mass of the lubrication rubber. This compounding scheme takes into account both the smooth filling properties of the rubber matrix and the lubrication and demolding properties of the mold interface, and realizes the synergistic optimization of filling performance and lubrication performance. (3) The uncured rubber of the present invention adopts a blend system of EPDM rubber and butadiene rubber with a mass ratio of (1.5-4):1. The flexibility and elasticity of the material can be balanced by blending modification, which provides basic performance guarantee for rheological filling under ultra-low pressure.

[0042] (4) In this invention, kaolin and silica are used as fillers in a mass ratio of (1-3):1. This can improve the mechanical strength of rubber, improve its processing performance and surface properties, and further optimize the filling effect under low pressure conditions. (5) The present invention adopts a segmented mixing process and controls the timing of adding each component by a specific feeding sequence, which effectively avoids the scorching of vulcanizing agent and the high-temperature decomposition of molding aid, ensuring the uniform dispersion of each component in the rubber matrix and improving the stability and batch consistency of material properties. (6) The preparation process of the present invention is simple and can be industrialized by conventional mixing equipment, which is convenient for promotion and implementation; the raw materials are readily available, the system is environmentally friendly, there is no release of harmful gases during use, and there is no risk of environmental pollution after disposal, which meets the requirements of green production. Attached Figure Description

[0043] Figure 1 This is a photograph of the actual test piece of the lubricating rubber used in Example 3; Figure 2 Here are detailed images of the actual test piece of the lubricating rubber used in Example 3; Figure 3 This is a physical image of the lubricating rubber used in Comparative Example 3. Figure 4 The image shows a detailed picture of the actual test piece of the lubricating rubber used in Comparative Example 3. Detailed Implementation

[0044] To address the aforementioned technical problems, this invention provides an ultra-low pressure filling lubricating rubber for semiconductor packaging and its preparation method. By introducing specific ultra-low pressure filling lubricating agents into the lubricating rubber and optimizing the formulation and process, the integrated synergy of gap filling and mold lubrication is achieved. While giving the rubber excellent flexible filling and fit, a uniform and stable lubricating layer can be formed on the mold surface, significantly improving demolding smoothness and extending mold service life. This solves the industry problem of traditional lubricating rubber's "difficulty in balancing filling and lubrication performance".

[0045] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0046] The following implementation examples involve some raw material information.

[0047] EPDM rubber: Uncured, sourced from Jilin Petrochemical Branch of China National Petroleum Corporation, model number J-4045.

[0048] Butadiene rubber: Uncured, sourced from Beijing Yanshan Branch of China Petroleum & Chemical Corporation, model number BR9000.

[0049] Kaolin: Sourced from Shanghai Heshuo International Trade Co., Ltd., manufactured by Burgess (USA), brand name SPOT WHITE.

[0050] Precipitated silica: sourced from Jinan Zhongbei Fine Chemical Co., Ltd., model number ZB-2000.

[0051] Vinyl polyphenylsiloxane: sourced from Zhejiang Runhe Catalyst Co., Ltd., model number RH-SP606.

[0052] Oxidation-modified polypropylene wax: sourced from Hengshui Yimei New Material Technology Co., Ltd., model number OPE829.

[0053] Examples 1-3 and Comparative Examples 1-3 Examples 1-3 and Comparative Examples 1-3 provide a lubricating rubber and its preparation method. The formulation of the lubricating rubber is shown in Tables 1 and 2 below. Table 1 shows the amount of raw materials added to the lubricating rubber in each example and comparative example, and Table 2 shows the ultra-low pressure filling lubricating agent used in the lubricating rubber of each example and comparative example.

[0054] Table 1

[0055] The values ​​in Table 1 are in parts by weight.

[0056] Table 2

[0057] The preparation steps of the lubricating rubber all include: S1. Using an SHR type high-speed mixer, the filler and vulcanizing agent are mixed evenly at 2000 rpm to obtain a premix; S2. Place the uncured rubber at 60°C and mix for 3 minutes. Then add the premix in 3 batches of equal mass. After each addition, mix at 90°C for 4 minutes. Then add the ultra-low pressure filler and mold lubricant at below 90°C and mix for 5 minutes to obtain the mixed material. S3. Place the mortar at room temperature (25°C) for 24 hours to obtain the molded rubber.

[0058] Performance testing The lubricating rubbers prepared in the above embodiments and comparative examples were subjected to processability tests, ultra-low pressure filling molding tests, lubrication ability tests, fracture degree tests, operability tests, lubrication cycle tests, packaging yield tests, and odor tests. The specific test methods are as follows, and the test results are shown in Table 3.

[0059] 1) Processability test: Observe whether there is uneven mixing of the raw materials for preparing the molding rubber during the S2 mixing and internal mixing process. If there is no uneven mixing, it is marked as OK; otherwise, it is marked as NG.

[0060] 2) Ultra-low pressure filling molding test: The prepared lubricating rubber is placed in the mold cavity of the semiconductor packaging mold and molded at a target temperature of 175℃ and a mold closing pressure of 20t for 5 minutes; after demolding, the mold cavity filling is observed. Complete filling is recorded as OK, otherwise it is recorded as NG.

[0061] 3) Operational test: After the mold is opened, remove the film on the mold. If it can be completely removed without the help of an air gun, it is marked as OK; otherwise, it is marked as NG.

[0062] 4) Fracture degree test: After the mold is opened, remove the lubricating film on the mold. If it breaks into 3 pieces or less, it is OK; otherwise, it is NG.

[0063] 5) Odor test: During the molding and packaging process at 175℃, observe whether there is any irritating odor, smoke or harmful volatile gas. If there is none, mark it as OK; otherwise, mark it as NG.

[0064] 6) Mold lubrication capability test: After the mold has been lubricated and sealed for 200 cycles, observe the number of times the mold sticks to the surface. If the number of sticking times is ≤3, it is considered OK; otherwise, it is considered NG.

[0065] 7) Lubrication cycle test: Record the effective lubrication cycle time of continuous packaging production. An effective lubrication cycle of ≥200 cycles is recorded as OK, otherwise it is recorded as NG.

[0066] 8) Packaging yield test: Use the mold after lubrication for batch packaging production, and count the yield of 1000 products. A yield of ≥95% is recorded as OK, otherwise it is recorded as NG.

[0067] Table 3

[0068] See the actual mold images after lubrication in Example 3 and Comparative Example 3. Figure 1-4 . Figure 1 , 2 As shown, the lubricating rubber of Example 3 can achieve complete filling of the mold cavity under molding conditions of 175°C and 20t, with clear mold cavity edge contours and no missing corner defects, exhibiting excellent low-pressure flowability and adhesion. Figure 3 , 4 As shown, the lubricating rubber of Comparative Example 3 could not completely fill the mold cavity under ultra-low pressure conditions, and there were obvious missing corners in the edge area of ​​the mold cavity (as shown in the red box), indicating that its fluidity and adhesion were insufficient under ultra-low pressure conditions, and it could not fill the entire mold cavity.

[0069] Table 3 and Figure 1-4 The test results show that Example 1, using 7 parts of vinyl-terminated polyphenylsiloxane as the ultra-low pressure filling and lubricating agent, produced a lubricating rubber with significantly improved ultra-low pressure filling molding properties, lubrication ability, operability, and breakage compared to the control example, meeting the qualified standards. Excellent processability was maintained, and the encapsulation yield increased to 95%, achieving basic compatibility with the ultra-low pressure process. Example 2, using 7 parts of oxidized modified polyolefin wax as the ultra-low pressure filling and lubricating agent, produced a lubricating rubber with further improved core properties compared to Example 1. Ultra-low pressure filling molding properties, lubrication ability, operability, breakage, lubrication cycle, and odor all met the superior standard, with excellent processability and an encapsulation yield of 96.6%. Example 3, using a 1:1 mass ratio of vinyl polyphenylsiloxane and oxidized modified polyolefin wax as the ultra-low pressure filling and lubricating agent, produced a lubricating rubber with an encapsulation yield of 98%, achieving optimal performance in all aspects.

[0070] Comparative Example 1, without the addition of ultra-low pressure filler and lubricant, exhibited poor flowability under ultra-low pressure conditions, failing to fill the fine cavities of the mold and resulting in substandard filling performance. The mold surface lacked an effective protective film, leading to up to 6 instances of mold sticking, indicating substandard lubrication. During demolding, the film was difficult to remove and broke into more than 3 pieces, with a lubrication cycle of only 100 cycles. Although this solution demonstrated excellent processability and odor control, its filling and lubrication performance failed to meet requirements, resulting in a packaging yield of only 76%, making it unsuitable for ultra-low pressure packaging processes. Comparative Example 2, with the addition of 10 parts of composite ultra-low pressure filler and lubricant, passed all performance tests except for processability testing, achieving a packaging yield of 97.8%. However, due to the excessive addition of ultra-low pressure filler and lubricant, some additives exhibited slight uneven dispersion in the rubber matrix, leading to substandard molding processability. Comparative Example 3 added 25 parts of composite ultra-low pressure filler and lubricant. Under ultra-low pressure, the rubber melt suffered from severe attenuation of the cohesive force between molecular chains and insufficient melt strength due to excessive filler. Stable and complete filling of fine cavities could not be achieved. At the same time, the system showed uneven dispersion of additives and severe sticking to the rollers during the mixing process, resulting in unqualified processability.

[0071] In summary, only by using the ultra-low pressure filling lubricant of this invention and controlling its addition within the preferred range can the lubricant rubber meet the requirements of multiple indicators such as processability, ultra-low pressure filling molding properties, lubrication ability, and packaging yield, thus satisfying the needs of semiconductor ultra-low pressure packaging processes.

Claims

1. A low-pressure filling lubricating rubber for semiconductor packaging, characterized in that, The raw materials for preparing the lubricating rubber include: uncured rubber, filler, ultra-low pressure filling lubricating agent, and vulcanizing agent; The amount of the ultra-low pressure filling lubricant added is 5-9 wt% of the total mass of the lubricating rubber; The uncured rubber includes EPDM rubber and butadiene rubber; the mass ratio of EPDM rubber to butadiene rubber is (1.5-4):1; The ultra-low pressure filling and damping agent includes at least one of oxidized modified polyolefin synthetic waxes and phenyl modified organosiloxanes; The mold closing pressure of the lubricating rubber is below 30t.

2. The ultra-low pressure filling and lubricating rubber for semiconductor packaging according to claim 1, characterized in that, The ultra-low pressure filling and lubricating agent includes oxidized modified polyolefin synthetic waxes and phenyl modified organosiloxanes; the mass ratio of the oxidized modified polyolefin synthetic waxes to the phenyl modified organosiloxanes is 1:(0.5-3).

3. The ultra-low pressure filling and lubricating rubber for semiconductor packaging according to claim 2, characterized in that, The ultra-low pressure filling and lubricating agent comprises oxidized modified polypropylene wax and vinyl-terminated polyphenylsiloxane in a mass ratio of 1:

1.

4. The ultra-low pressure filling and lubricating rubber for semiconductor packaging according to claim 1, characterized in that, The filler includes one or more of the following: silica, zinc barium white, quartz sand, talc, kaolin, and titanium dioxide.

5. The ultra-low pressure filling and lubricating rubber for semiconductor packaging according to claim 4, characterized in that, The filler comprises kaolin and silica, wherein the mass ratio of kaolin to silica is (1-3):

1.

6. The ultra-low pressure filling lubricating rubber for semiconductor packaging according to claim 1, characterized in that, The vulcanizing agent includes at least one of peroxide vulcanizing agents and sulfur vulcanizing agents.

7. The ultra-low pressure filling and lubricating rubber for semiconductor packaging according to claim 6, characterized in that, The vulcanizing agent includes DCP.

8. A method for preparing ultra-low pressure filling lubricating rubber for semiconductor packaging according to any one of claims 1-7, characterized in that, The preparation steps of the lubricating rubber include: The filler and vulcanizing agent are mixed evenly to obtain a premix; Uncured rubber is mixed at 50-70℃ for 1-5 minutes, then premixed in batches and mixed at 80-95℃ for 5-15 minutes; then ultra-low pressure filler and mold lubricant are added at below 90℃ and mixed for 2-10 minutes to obtain the mixed material. Cool the mortar to obtain a lubricated rubber.

9. The method for preparing ultra-low pressure filling lubricating rubber for semiconductor packaging according to claim 8, characterized in that, The premixed material is added in three batches, with each batch requiring 3-5 minutes of internal mixing.

10. A method of using the ultra-low pressure filling lubricating rubber for semiconductor packaging according to any one of claims 1-7, characterized in that, The temperature of the lubricating rubber during the lubrication operation is 150-190℃, and the mold closing pressure is 10-30t.

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