A low warpage copper clad laminate and its manufacturing process

Abstract

This invention discloses a low-warpage copper-clad laminate and its preparation process, belonging to the field of copper-clad laminate technology. The low-warpage copper-clad laminate disclosed in this invention is prepared by first completely and uniformly impregnating glass fiber cloth with copper-clad laminate adhesive and then drying it to obtain a semi-cured sheet; then taking several semi-cured sheets with flat surfaces and uniform coatings, stacking them, attaching copper foil on the top and bottom, and hot pressing them to obtain the final product; the invention is characterized in that the copper-clad laminate adhesive, by weight, comprises: 80-100 parts by weight of epoxy resin, 44-55 parts by weight of low-shrinkage curing agent, 1.6-2 parts by weight of accelerator, 10-30 parts by weight of flame retardant, and 90-110 parts by weight of solvent.

Description

Technical Field

[0001] This invention relates to a low warpage copper clad laminate and its manufacturing process. Background Technology

[0002] In modern electronics manufacturing, copper clad laminate (CCL) is a fundamental material for printed circuit boards (PCBs), and its quality directly affects the performance and reliability of the PCB. CEM-1 type CCL, in particular, is widely used in multilayer and double-sided boards due to its high cost-effectiveness and good mechanical strength. However, CEM-1 CCL warping (hereinafter referred to as substrate warping) is a product defect that is of great concern to CCL manufacturers, PCB manufacturers, and related users, yet it is also very difficult to resolve. It is also a major concern for electronics assembly plants and related users.

[0003] Substrate warping not only affects the smooth progress of PCB manufacturing processes, such as causing pattern deformation or board jamming on automated PCB production lines, but also hinders the automated insertion and placement of electronic components. More seriously, substrate warping can cause integrated circuit contacts to fail to make proper contact with PCB pads, and the stress generated by warping can also cause contact breakage, leading to an increased scrap rate. Furthermore, substrate warping also poses challenges to the installation and use of electronic devices; for example, the PCB may be difficult to insert into a socket, and even if successfully inserted, poor contact may affect the device's functionality.

[0004] To address the issue of substrate warpage, the applicant designed a low-warpage copper-clad laminate and its fabrication process. Summary of the Invention

[0005] The purpose of this invention is to provide a low-warpage copper-clad laminate and its manufacturing process to solve the technical problems mentioned in the background section.

[0006] The technical solution to achieve the objective of this invention is:

[0007] A low-warpage copper-clad laminate is provided, wherein the low-warpage copper-clad laminate is first obtained by completely and uniformly impregnating glass fiber cloth with copper-clad laminate adhesive and then drying it to obtain a prepreg; then several prepreg sheets with flat surfaces and uniform coating are stacked together, and copper foil is attached to the top and bottom and hot-pressed to obtain the laminate; the copper-clad laminate adhesive comprises, by weight, 80-100 parts epoxy resin, 44-55 parts low-shrinkage curing agent, 1.6-2 parts accelerator, 10-30 parts flame retardant, and 90-110 parts solvent.

[0008] Furthermore, the low-shrinkage curing agent is obtained by compounding polycarboxylated POSS and thioctic acid.

[0009] Furthermore, the accelerator is accelerator DMP-30.

[0010] Furthermore, the flame retardant is any one of toluene diphenyl ester, trichloropropyl phosphate, DOPO, and hexaphenoxycyclotriphosphazene.

[0011] Furthermore, the solvent is a mixture of butanone and propylene glycol methyl ether acetate.

[0012] Furthermore, a fabrication process for a low-warpage copper-clad laminate includes the following steps:

[0013] (1) Preparation of copper clad laminate adhesive: After cleaning the adhesive tank, add 90-110 parts by weight of solvent to the adhesive tank, then add 80-100 parts by weight of epoxy resin and 44-55 parts by weight of low shrinkage curing agent, stir at 70-90 r / min for 2.5-3.5 h to mix evenly, then add 1.6-2 parts by weight of accelerator and 10-30 parts by weight of flame retardant, stir at 800-1200 rpm for 5-7 h, remove bubbles after curing to obtain copper clad laminate adhesive;

[0014] (2) Preparation of semi-cured sheet: The copper-clad laminate adhesive is completely and evenly impregnated with glass fiber cloth and then placed in an oven at 115~125℃ for baking to obtain a semi-cured sheet. The adhesive content is controlled to be about 45% and the flowability is about 30%.

[0015] (3) Take several flat and evenly coated semi-cured sheets, stack them, attach copper foil on the top and bottom, place them in a vacuum hot press with a pressure of 5~17MPa and a temperature of 160~180℃, hot press for 90~130min and keep warm for 0.8~1.2h.

[0016] Furthermore, the warp yarn count of the glass cloth is 38-42 yarns / inch, and the weft yarn count is 36-40 yarns / inch.

[0017] Furthermore, the low-shrinkage curing agent is obtained by mixing polycarboxylated POSS and thioctic acid in a mass ratio of 2 to 4:1.

[0018] Further, the preparation steps of the polycarboxylated POSS are as follows: 44-46 parts by mass of acrylic acid, 0.4-0.6 parts by mass of cage-type octavinylsilsesquioxane, 4-6 parts by mass of tetrahydrofuran, 0.9-1.1 parts by mass of sodium dodecyl sulfate, and 38-42 parts by mass of deionized water are mixed and stirred at 80-90°C for 55-65 minutes. 11-13 parts by mass of potassium persulfate are added in three equal portions in three separate additions, with an interval of 30 minutes between each addition. After the addition is complete, the reaction is carried out for 5-7 hours to obtain the polycarboxylated POSS.

[0019] Further, the preparation steps of the cage-type octavinylsilsesquioxane are as follows: 400 parts by mass of acetone and 62-64 parts by mass of vinyltrimethoxysilane are mixed, and 129-131 parts by mass of 37% hydrochloric acid solution and 100-120 parts by mass of deionized water are added dropwise at 4-6 drops / s. After the addition is completed, the mixture is reacted at 30-50°C for 47-49 hours, cooled, filtered, washed, and dried to obtain the cage-type octavinylsilsesquioxane.

[0020] By adopting the above technical solution, the present invention has the following beneficial effects:

[0021] (1) The present invention improves the copper clad laminate adhesive by introducing a low shrinkage curing agent to reduce the curing shrinkage of epoxy resin, thereby shortening the shrinkage difference between epoxy resin and glass cloth and copper foil, thereby reducing the internal stress generated inside the product after curing, and thus reducing the warpage of copper clad laminate.

[0022] (2) The low shrinkage curing agent of the present invention is obtained by compounding polycarboxylated POSS and thioctic acid. By introducing polycarboxylated POSS, the curing agent can add a rigid POSS structure to the copper clad laminate adhesive, thereby toughening and modifying the adhesive, thereby reducing the curing shrinkage rate of the copper clad laminate adhesive. At the same time, the addition of POSS greatly increases the number of silicon-oxygen bonds and carbon-silicon bonds, effectively reducing the number of polarized molecules per unit volume. Moreover, the POSS structure has its own cavity characteristics, which effectively reduces the dielectric constant and dielectric loss of the copper clad laminate adhesive. Even if volume shrinkage inevitably occurs during the curing process, the introduction of thioctic acid can cause the polymer network of the prepreg to be destroyed and rearranged in the subsequent hot pressing step, while maintaining the crosslinking density basically unchanged, ensuring that the mechanical properties of the copper clad laminate are not affected. At the same time, it effectively reduces the stress caused by volume shrinkage, thereby reducing the warping phenomenon of the copper clad laminate.

[0023] (3) Compared with traditional glass cloth with a warp yarn density of 42-46 threads / inch and a weft yarn density of 32-36 threads / inch, the glass cloth of the present invention has a warp yarn density of 38-42 threads / inch and a weft yarn density of 36-40 threads / inch. The number of threads per inch in the warp and weft directions is more similar, and the distribution of adhesive in the glass cloth is more uniform, thereby reducing the problem of inconsistent curing shrinkage caused by the difference in yarn density. This not only improves the consistency of curing shrinkage rate in the radial and weft directions of the glass cloth, but also effectively reduces the warping phenomenon of copper clad laminate during the curing process. Detailed Implementation

[0024] To better understand the above technical solution, the following will provide a detailed explanation of the technical solution in conjunction with specific implementation methods.

[0025] The following embodiments are only used to illustrate the technical solutions of the present invention more clearly, and should not be used to limit the scope of protection of the present invention.

[0026] The following are some of the raw materials used in the embodiments and comparative examples of this invention:

[0027] The epoxy resin used is bisphenol A type epoxy resin;

[0028] The flame retardant used is toluene diphenyl ester;

[0029] The solvent used is a mixture of butanone and propylene glycol methyl ether acetate in a mass ratio of 11:9;

[0030] The accelerator used is DMP-30.

[0031] (Example 1)

[0032] A fabrication process for a low-warpage copper-clad laminate includes the following steps:

[0033] (1) Preparation of copper clad laminate adhesive: After cleaning the adhesive tank, add 90 parts by mass of solvent to the adhesive tank, then add 80 parts by mass of epoxy resin and 44 parts by mass of low shrinkage curing agent, stir at 70 r / min for 2.5 h to mix evenly, then add 1.6 parts by mass of accelerator and 10 parts by mass of flame retardant, stir at 800 rpm for 5 h, remove bubbles after curing, and obtain copper clad laminate adhesive;

[0034] (2) Preparation of semi-cured sheet: The copper-clad laminate adhesive is completely and evenly impregnated with glass fiber cloth and then placed in an oven at 115℃ for baking to obtain a semi-cured sheet. The adhesive content is controlled to be about 45% and the flowability is about 30%.

[0035] (3) Take several flat and evenly coated semi-cured sheets, stack them, attach copper foil on the top and bottom, place them in a vacuum hot press with a pressure of 5MPa and a temperature of 160℃, hot press for 90min and keep warm for 0.8h.

[0036] The glass cloth has a warp yarn count of 38 yarns / inch and a weft yarn count of 36 yarns / inch.

[0037] The low-shrinkage curing agent is obtained by mixing polycarboxylated POSS and thioctic acid in a mass ratio of 2:1.

[0038] The preparation steps of the polycarboxylated POSS are as follows: 44 parts by mass of acrylic acid, 0.4 parts by mass of cage-type octavinylsilsesquioxane, 4 parts by mass of tetrahydrofuran, 0.9 parts by mass of sodium dodecyl sulfate and 38 parts by mass of deionized water are mixed and stirred at 80°C for 55 min. 11 parts by mass of potassium persulfate are added in three equal parts in three batches, with an interval of 30 min between each addition. After the addition is completed, the reaction is carried out for 5 h to obtain polycarboxylated POSS.

[0039] The preparation steps of the cage-type octavinylsilsesquioxane are as follows: 400 parts by mass of acetone and 62 parts by mass of vinyltrimethoxysilane are mixed, and 129 parts by mass of 37% hydrochloric acid solution and 100 parts by mass of deionized water are added dropwise at 4 drops / s. After the addition is completed, the mixture is reacted at 30°C for 47 hours, cooled, filtered, washed and dried to obtain the cage-type octavinylsilsesquioxane.

[0040] (Example 2)

[0041] A fabrication process for a low-warpage copper-clad laminate includes the following steps:

[0042] (1) Preparation of copper clad laminate adhesive: After cleaning the adhesive tank, add 100 parts by weight of solvent to the adhesive tank, then add 90 parts by weight of epoxy resin and 50 parts by weight of low shrinkage curing agent, stir at 80 r / min for 3 h to mix evenly, then add 1.8 parts by weight of accelerator and 20 parts by weight of flame retardant, stir at 1000 rpm for 6 h, remove bubbles after curing, and obtain copper clad laminate adhesive;

[0043] (2) Preparation of semi-cured sheet: The copper-clad laminate adhesive is completely and evenly impregnated with glass fiber cloth and then placed in an oven at 120°C for baking to obtain a semi-cured sheet. The adhesive content is controlled to be about 45% and the flowability is about 30%.

[0044] (3) Take several flat and evenly coated semi-cured sheets, stack them, attach copper foil on the top and bottom, place them in a vacuum hot press with a pressure of 11MPa and a temperature of 170℃, hot press for 110min and keep warm for 1h.

[0045] The glass cloth has a warp yarn count of 40 yarns / inch and a weft yarn count of 38 yarns / inch.

[0046] The low-shrinkage curing agent is obtained by mixing polycarboxylated POSS and thioctic acid in a mass ratio of 3:1.

[0047] The preparation steps of the polycarboxylated POSS are as follows: 45 parts by mass of acrylic acid, 0.5 parts by mass of cage-type octavinylsilsesquioxane, 5 parts by mass of tetrahydrofuran, 1 part by mass of sodium dodecyl sulfate and 40 parts by mass of deionized water are mixed and stirred at 85°C for 60 min. 12 parts by mass of potassium persulfate are added in three equal parts in three batches, with an interval of 30 min between each addition. After the addition is completed, the reaction is carried out for 6 h to obtain polycarboxylated POSS.

[0048] The preparation steps of the cage-type octavinylsilsesquioxane are as follows: 400 parts by mass of acetone and 63 parts by mass of vinyltrimethoxysilane are mixed, and 130 parts by mass of 37% hydrochloric acid solution and 110 parts by mass of deionized water are added dropwise at 5 drops / s. After the addition is completed, the mixture is reacted at 40°C for 48 hours, cooled, filtered, washed and dried to obtain the cage-type octavinylsilsesquioxane.

[0049] (Example 3)

[0050] A fabrication process for a low-warpage copper-clad laminate includes the following steps:

[0051] (1) Preparation of copper clad laminate adhesive: After cleaning the adhesive tank, add 110 parts by weight of solvent to the adhesive tank, then add 100 parts by weight of epoxy resin and 55 parts by weight of low shrinkage curing agent, stir at 90 r / min for 3.5 h to mix evenly, then add 2 parts by weight of accelerator and 30 parts by weight of flame retardant, stir at 1200 rpm for 7 h, remove bubbles after curing, and obtain copper clad laminate adhesive;

[0052] (2) Preparation of semi-cured sheet: The copper-clad laminate adhesive is completely and evenly impregnated with glass fiber cloth and then placed in an oven at 125°C for baking to obtain a semi-cured sheet. The adhesive content is controlled to be about 45% and the flowability is about 30%.

[0053] (3) Take several flat and evenly coated semi-cured sheets, stack them, attach copper foil on the top and bottom, place them in a vacuum hot press with a pressure of 17MPa and a temperature of 180℃, hot press for 130min and keep warm for 1.2h.

[0054] The glass cloth has a warp yarn count of 42 yarns / inch and a weft yarn count of 40 yarns / inch.

[0055] The low-shrinkage curing agent is obtained by mixing polycarboxylated POSS and thioctic acid in a mass ratio of 4:1.

[0056] The preparation steps of the polycarboxylated POSS are as follows: 46 parts by mass of acrylic acid, 0.6 parts by mass of cage-type octavinylsilsesquioxane, 6 parts by mass of tetrahydrofuran, 1.1 parts by mass of sodium dodecyl sulfate and 42 parts by mass of deionized water are mixed and stirred at 90°C for 65 min. 13 parts by mass of potassium persulfate are added in three equal parts in three batches, with an interval of 30 min between each addition. After the addition is completed, the reaction is carried out for 7 h to obtain polycarboxylated POSS.

[0057] The preparation steps of the cage-type octavinylsilsesquioxane are as follows: 400 parts by mass of acetone and 64 parts by mass of vinyltrimethoxysilane are mixed, and 131 parts by mass of 37% hydrochloric acid solution and 120 parts by mass of deionized water are added dropwise at 6 drops / s. After the addition is completed, the mixture is reacted at 50°C for 49 hours, cooled, filtered, washed and dried to obtain the cage-type octavinylsilsesquioxane.

[0058] (Comparative Example 1)

[0059] A fabrication process for a low-warpage copper-clad laminate includes the following steps:

[0060] (1) Preparation of copper clad laminate adhesive: After cleaning the adhesive tank, add 100 parts by weight of solvent to the adhesive tank, then add 90 parts by weight of epoxy resin and 50 parts by weight of low shrinkage curing agent, stir at 80 r / min for 3 h to mix evenly, then add 1.8 parts by weight of accelerator and 20 parts by weight of flame retardant, stir at 1000 rpm for 6 h, remove bubbles after curing, and obtain copper clad laminate adhesive;

[0061] (2) Preparation of semi-cured sheet: The copper-clad laminate adhesive is completely and evenly impregnated with glass fiber cloth and then placed in an oven at 120°C for baking to obtain a semi-cured sheet. The adhesive content is controlled to be about 45% and the flowability is about 30%.

[0062] (3) Take several flat and evenly coated semi-cured sheets, stack them, attach copper foil on the top and bottom, place them in a vacuum hot press with a pressure of 11MPa and a temperature of 170℃, hot press for 110min and keep warm for 1h.

[0063] The glass cloth has a warp yarn count of 40 yarns / inch and a weft yarn count of 38 yarns / inch.

[0064] The low-shrinkage curing agent uses only polycarboxylated POSS.

[0065] The preparation steps of the polycarboxylated POSS are as follows: 45 parts by mass of acrylic acid, 0.5 parts by mass of cage-type octavinylsilsesquioxane, 5 parts by mass of tetrahydrofuran, 1 part by mass of sodium dodecyl sulfate and 40 parts by mass of deionized water are mixed and stirred at 85°C for 60 min. 12 parts by mass of potassium persulfate are added in three equal parts in three batches, with an interval of 30 min between each addition. After the addition is completed, the reaction is carried out for 6 h to obtain polycarboxylated POSS.

[0066] The preparation steps of the cage-type octavinylsilsesquioxane are as follows: 400 parts by mass of acetone and 63 parts by mass of vinyltrimethoxysilane are mixed, and 130 parts by mass of 37% hydrochloric acid solution and 110 parts by mass of deionized water are added dropwise at 5 drops / s. After the addition is completed, the mixture is reacted at 40°C for 48 hours, cooled, filtered, washed and dried to obtain the cage-type octavinylsilsesquioxane.

[0067] (Comparative Example 2)

[0068] A fabrication process for a low-warpage copper-clad laminate includes the following steps:

[0069] (1) Preparation of copper clad laminate adhesive: After cleaning the adhesive tank, add 100 parts by weight of solvent to the adhesive tank, then add 90 parts by weight of epoxy resin and 50 parts by weight of low shrinkage curing agent, stir at 80 r / min for 3 h to mix evenly, then add 1.8 parts by weight of accelerator and 20 parts by weight of flame retardant, stir at 1000 rpm for 6 h, remove bubbles after curing, and obtain copper clad laminate adhesive;

[0070] (2) Preparation of semi-cured sheet: The copper-clad laminate adhesive is completely and evenly impregnated with glass fiber cloth and then placed in an oven at 120°C for baking to obtain a semi-cured sheet. The adhesive content is controlled to be about 45% and the flowability is about 30%.

[0071] (3) Take several flat and evenly coated semi-cured sheets, stack them, attach copper foil on the top and bottom, place them in a vacuum hot press with a pressure of 11MPa and a temperature of 170℃, hot press for 110min and keep warm for 1h.

[0072] The glass cloth has a warp yarn count of 40 yarns / inch and a weft yarn count of 38 yarns / inch.

[0073] The low-shrinkage curing agent is obtained by mixing maleic anhydride and thioctic acid in a mass ratio of 3:1.

[0074] (Comparative Example 3)

[0075] A fabrication process for a low-warpage copper-clad laminate includes the following steps:

[0076] (1) Preparation of copper clad laminate adhesive: After cleaning the adhesive tank, add 100 parts by weight of solvent to the adhesive tank, then add 90 parts by weight of epoxy resin and 50 parts by weight of curing agent, stir at 80 r / min for 3 h to mix evenly, then add 1.8 parts by weight of accelerator and 20 parts by weight of flame retardant, stir at 1000 rpm for 6 h, remove bubbles after curing, and obtain copper clad laminate adhesive;

[0077] (2) Preparation of semi-cured sheet: The copper-clad laminate adhesive is completely and evenly impregnated with glass fiber cloth and then placed in an oven at 120°C for baking to obtain a semi-cured sheet. The adhesive content is controlled to be about 45% and the flowability is about 30%.

[0078] (3) Take several flat and evenly coated semi-cured sheets, stack them, attach copper foil on the top and bottom, place them in a vacuum hot press with a pressure of 11MPa and a temperature of 170℃, hot press for 110min and keep warm for 1h.

[0079] The glass cloth has a warp yarn count of 40 yarns / inch and a weft yarn count of 38 yarns / inch.

[0080] The curing agent is maleic anhydride.

[0081] (Comparative Example 4)

[0082] A fabrication process for a low-warpage copper-clad laminate includes the following steps:

[0083] (1) Preparation of copper clad laminate adhesive: After cleaning the adhesive tank, add 100 parts by weight of solvent to the adhesive tank, then add 90 parts by weight of epoxy resin and 50 parts by weight of low shrinkage curing agent, stir at 80 r / min for 3 h to mix evenly, then add 1.8 parts by weight of accelerator and 20 parts by weight of flame retardant, stir at 1000 rpm for 6 h, remove bubbles after curing, and obtain copper clad laminate adhesive;

[0084] (2) Preparation of semi-cured sheet: The copper-clad laminate adhesive is completely and evenly impregnated with glass fiber cloth and then placed in an oven at 120°C for baking to obtain a semi-cured sheet. The adhesive content is controlled to be about 45% and the flowability is about 30%.

[0085] (3) Take several flat and evenly coated semi-cured sheets, stack them, attach copper foil on the top and bottom, place them in a vacuum hot press with a pressure of 11MPa and a temperature of 170℃, hot press for 110min and keep warm for 1h.

[0086] The glass cloth has a warp yarn count of 44 yarns / inch and a weft yarn count of 34 yarns / inch.

[0087] The low-shrinkage curing agent is obtained by mixing polycarboxylated POSS and thioctic acid in a mass ratio of 3:1.

[0088] The preparation steps of the polycarboxylated POSS are as follows: 45 parts by mass of acrylic acid, 0.5 parts by mass of cage-type octavinylsilsesquioxane, 5 parts by mass of tetrahydrofuran, 1 part by mass of sodium dodecyl sulfate and 40 parts by mass of deionized water are mixed and stirred at 85°C for 60 min. 12 parts by mass of potassium persulfate are added in three equal parts in three batches, with an interval of 30 min between each addition. After the addition is completed, the reaction is carried out for 6 h to obtain polycarboxylated POSS.

[0089] The preparation steps of the cage-type octavinylsilsesquioxane are as follows: 400 parts by mass of acetone and 63 parts by mass of vinyltrimethoxysilane are mixed, and 130 parts by mass of 37% hydrochloric acid solution and 110 parts by mass of deionized water are added dropwise at 5 drops / s. After the addition is completed, the mixture is reacted at 40°C for 48 hours, cooled, filtered, washed and dried to obtain the cage-type octavinylsilsesquioxane.

[0090] (Comparative Example 5)

[0091] A fabrication process for a low-warpage copper-clad laminate includes the following steps:

[0092] (1) Preparation of copper clad laminate adhesive: After cleaning the adhesive tank, add 100 parts by weight of solvent to the adhesive tank, then add 90 parts by weight of epoxy resin and 50 parts by weight of curing agent, stir at 80 r / min for 3 h to mix evenly, then add 1.8 parts by weight of accelerator and 20 parts by weight of flame retardant, stir at 1000 rpm for 6 h, remove bubbles after curing, and obtain copper clad laminate adhesive;

[0093] (2) Preparation of semi-cured sheet: The copper-clad laminate adhesive is completely and evenly impregnated with glass fiber cloth and then placed in an oven at 120°C for baking to obtain a semi-cured sheet. The adhesive content is controlled to be about 45% and the flowability is about 30%.

[0094] (3) Take several flat and evenly coated semi-cured sheets, stack them, attach copper foil on the top and bottom, place them in a vacuum hot press with a pressure of 11MPa and a temperature of 170℃, hot press for 110min and keep warm for 1h.

[0095] The glass cloth has a warp yarn count of 44 yarns / inch and a weft yarn count of 34 yarns / inch.

[0096] The curing agent is maleic anhydride.

[0097] Example of effect

[0098] Warpage: The low warpage copper clad laminates prepared in the examples and comparative examples were tested for warpage according to JIS C 6481 standard.

[0099] Dielectric constant and dielectric loss: The low warpage copper clad laminates prepared in the examples and comparative examples were measured at 10 GHz using the planar method according to IPC-TM-6502.5.5.9.

[0100] Toughness: Using an impact tester, the drop height of the hammer is 45cm, and the weight of the falling hammer is 1kg. Judgment of toughness: A clear cross indicates better toughness, represented by character ①; a blurry cross indicates poor toughness and brittleness, represented by character ②; a cross clarity between clear and blurry indicates average toughness, represented by character ③.

[0101] Table 1 below shows the performance test data of the low warpage copper clad laminates prepared in the examples and comparative examples:

[0102] Table 1

[0103]

[0104] As shown in Table 1, the low-warpage copper-clad laminates prepared in Examples 1-3 have lower dielectric constants, lower dielectric losses, lower warpage, and better toughness. The difference between Comparative Example 1 and Example 2 is that Comparative Example 1 uses only polycarboxylated POSS as its low-shrinkage curing agent. Compared to Example 2, Comparative Example 2 has lower warpage. The difference between Comparative Example 2 and Example 2 is that Comparative Example 2 uses a low-shrinkage curing agent obtained by mixing maleic anhydride and thioctic acid in a mass ratio of 3:1. Compared to Example 2, Comparative Example 2 has lower dielectric constants, lower dielectric losses, lower warpage, and better toughness. The difference between Comparative Example 3 and Example 2 is that Comparative Example 3 uses only maleic anhydride as its curing agent. Compared with Example 2, Example 2 has lower dielectric constant, dielectric loss, warpage, and toughness. The difference between Comparative Example 4 and Example 2 is that the warp yarn density of the glass cloth in Comparative Example 4 is 44 yarns / inch and the weft yarn density is 34 yarns / inch. Compared with Example 2, Example 2 has lower warpage. The difference between Comparative Example 5 and Example 2 is that the curing agent in Comparative Example 5 is only maleic anhydride, and the warp yarn density of the glass cloth is 44 yarns / inch and the weft yarn density is 34 yarns / inch. Compared with Example 2, Example 2 has lower dielectric constant, dielectric loss, warpage, and toughness.

[0105] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A process for manufacturing a low-warpage copper-clad laminate, characterized in that, The preparation steps include the following: (1) Preparation of copper clad laminate adhesive: After cleaning the adhesive tank, add 90-110 parts by weight of solvent to the adhesive tank, then add 80-100 parts by weight of bisphenol A epoxy resin and 44-55 parts by weight of low shrinkage curing agent, stir at 70-90 r / min for 2.5-3.5 h to mix evenly, then add 1.6-2 parts by weight of accelerator and 10-30 parts by weight of flame retardant, stir at 800-1200 rpm for 5-7 h, remove air bubbles, and obtain copper clad laminate adhesive; (2) Preparation of semi-cured sheet: The copper-clad laminate adhesive is completely and uniformly impregnated with glass fiber cloth and then placed in an oven at 115~125℃ for baking to obtain a semi-cured sheet. The adhesive content is controlled at 45% and the flowability is 30%. (3) Take several flat and evenly coated semi-cured sheets, stack them, attach copper foil on the top and bottom, and place them in a vacuum hot press with a pressure of 5~17MPa and a temperature of 160~180℃. Press for 90~130min and keep warm for 0.8~1.2h. The warp yarn count of the glass fiber cloth is 38-42 yarns / inch, and the weft yarn count is 36-40 yarns / inch. The low-shrinkage curing agent is obtained by mixing polycarboxylated POSS and thioctic acid in a mass ratio of 2-4:

1. The preparation steps of the polycarboxylated POSS are as follows: 44-46 parts by weight of acrylic acid, 0.4-0.6 parts by weight of cage-type octavinylsilsesquioxane, 4-6 parts by weight of tetrahydrofuran, 0.9-1.1 parts by weight of sodium dodecyl sulfate and 38-42 parts by weight of deionized water are mixed and stirred at 80-90°C for 55-65 min. 11-13 parts by weight of potassium persulfate are added in three equal parts in three batches, with an interval of 30 min between each addition. After the addition is completed, the reaction is carried out for 5-7 h to obtain polycarboxylated POSS. The preparation steps of the cage-type octavinylsilsesquioxane are as follows: 400 parts by mass of acetone and 62-64 parts by mass of vinyltrimethoxysilane are mixed, and 129-131 parts by mass of 37% hydrochloric acid solution and 100-120 parts by mass of deionized water are added dropwise at 4-6 drops / s. After the addition is completed, the mixture is reacted at 30-50℃ for 47-49 hours, cooled, filtered, washed, and dried to obtain the cage-type octavinylsilsesquioxane.

2. A low-warpage copper-clad laminate prepared by the manufacturing process of the low-warpage copper-clad laminate as described in claim 1, wherein the low-warpage copper-clad laminate is prepared by first completely and uniformly impregnating glass fiber cloth with copper-clad laminate adhesive and then drying it to obtain a prepreg; subsequently, several prepreg sheets with flat surfaces and uniform coatings are stacked, and copper foil is attached to the top and bottom and hot-pressed to obtain the laminate; characterized in that, The copper-clad laminate adhesive comprises, by weight, 80-100 parts of bisphenol A epoxy resin, 44-55 parts of low-shrinkage curing agent, 1.6-2 parts of accelerator, 10-30 parts of flame retardant, and 90-110 parts of solvent.

3. The low warpage copper-clad laminate according to claim 2, characterized in that, The low-shrinkage curing agent is obtained by compounding polycarboxylated POSS and thioctic acid.

4. The low warpage copper-clad laminate according to claim 2, characterized in that, The accelerator used is accelerator DMP-30.

5. The low warpage copper-clad laminate according to claim 2, characterized in that, The flame retardant is any one of trichloropropyl phosphate, DOPO, or hexaphenoxycyclotriphosphazene.

6. The low warpage copper-clad laminate according to claim 2, characterized in that, The solvent is a mixture of butanone and propylene glycol methyl ether acetate.

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