Surface chemical modification substrate and preparation method thereof

Abstract

The invention relates to a surface chemical modification substrate and a preparation method thereof. According to the preparation method, surface modification is realized by utilizing the characteristic that a catechol modifier such as dihydroxyphenylalanine or dopamine can be subjected to auto-polymerization deposition on the surface of a resin substrate. After modification, new polar groups such as hydroxyl, carboxyl and amino can be generated on the surface of the substrate, and the polar groups can increase the chemical bonding effect between the substrate and copper and improve the interface bonding force.

Description

Technical Field

[0001] The present invention relates to the technical field of chip packaging, and in particular to a surface chemically modified substrate and a preparation method thereof. Background Art

[0002] Epoxy-phenol resin-based substrates are already widely used in the manufacture of FCBGA (Flip Chip Ball Grid Array) substrates. However, due to the high degree of surface roughness of these substrates, copper plating increases the risk of permeation during surface plating, increasing signal transmission loss and restricting the manufacture of fine circuits on the substrates, thus limiting the application and development of large-scale substrates. Epoxy-phenolic resin-based and epoxy-cyanate resin-based substrates do not suffer from these drawbacks and are suitable for large-scale substrate manufacturing. However, due to their extremely high filler loading and smaller filler size, the chemical bonding and mechanical interlocking effects of the substrate surface are greatly weakened, significantly limiting the level of heterogeneous interface bonding strength on the substrates and hindering the manufacture and application of large-scale substrates.

[0003] Therefore, it is necessary to improve the substrate surface to enhance the bonding strength of the substrate heterogeneous interface. Summary of the Invention

[0004] In order to solve the problems existing in the background technology, the present invention provides a method for preparing a surface chemically modified substrate, which realizes chemical modification of the substrate surface and improves the bonding strength level of the heterogeneous interface of the substrate.

[0005] Specifically, the first aspect of the present invention provides a method for preparing a surface chemically modified substrate, comprising the following steps:

[0006] placing a resin substrate in a catechol monomer solution to allow the catechol monomer to undergo a self-polymerization reaction, and the generated polymer is deposited on the surface of the resin substrate;

[0007] Wherein, the catechol monomer is dihydroxyphenylalanine or dopamine.

[0008] The present invention uses catechol-based modifiers, such as dihydroxyphenylalanine or dopamine, to chemically modify the surface of a resin substrate. The catechol monomers undergo autopolymerization and adhere to the substrate surface, thereby modifying the substrate surface. This modification generates new polar groups, such as hydroxyl, carboxyl, and amino groups, on the substrate surface. These polar groups enhance the chemical bonding between the substrate and copper, improving interfacial adhesion.

[0009] Compared with other modifiers, dihydroxyphenylalanine and dopamine have the characteristics of extremely strong viscosity, high thermal stability, good water solubility, mild chemical modification conditions (normal pressure and room temperature), non-volatility, non-corrosiveness, no special odor, and non-toxicity, making them extremely suitable for substrate wet processing.

[0010] In some embodiments, the pH value of the catechol monomer solution may be 8-9, for example, 8, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9 or 9.

[0011] In some embodiments, the self-polymerization reaction time may be 5 min-10 h, for example, 5 min, 10 min, 30 min, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 5.5 h, 6 h, 6.5 h, 7 h, 7.5 h, 8 h, 8.5 h, 9 h, 9.5 h, or 10 h. The catechol monomer solution may be an aqueous solution of catechol monomers. The catechol monomer solution may undergo self-polymerization in water, and the reaction conditions are mild, such as normal pressure and room temperature.

[0012] In some embodiments, before placing the resin substrate in the catechol monomer solution, the preparation method further includes placing the resin substrate in an oxidant solution for oxidation. The oxidation treatment can destroy the resin macromolecular chains on the surface of the resin substrate, roughening the surface of the resin substrate. This facilitates the self-polymerization of dihydroxyphenylalanine and dopamine and their deposition on the surface of the resin substrate, thereby improving adhesion.

[0013] In some embodiments, the oxidant may be one or more of potassium permanganate, hydrogen peroxide, peracetic acid, sodium dichromate, chromic acid, nitric acid, ammonium persulfate, sodium hypochlorite, sodium percarbonate, sodium perborate, and potassium perborate. The oxidation temperature may be 70-90°C, for example, 70°C, 75°C, 80°C, 85°C, or 90°C. Too high an oxidation temperature will accelerate the excessive roughening of the surface of the deposited film, while too low an oxidation temperature will cause the surface roughening rate to be too slow and the degree of surface roughening to be low. The oxidation time may be 5-15 minutes, for example, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, or 15 minutes. If the oxidation time is too long, the surface resin will be excessively removed, which will not only reduce the roughness but also significantly reduce the thickness of the deposited film; and if the oxidation time is too short, the surface roughening will not be sufficient.

[0014] In some embodiments, the resin substrate includes a core plate and a resin deposition film disposed on the upper and lower surfaces of the core plate. The resin deposition film is made of a mixture of a polymer resin and a silica filler. The core plate is a silicon substrate, a ceramic substrate, a glass substrate, or an epoxy resin composite material composed of epoxy resin and glass fiber.

[0015] According to the filling amount of silicon oxide filler, the resin stacking film can be divided into low-filling resin stacking film, high-filling resin stacking film and ultra-high-filling resin stacking film. Filling fillers will weaken the chemical bonding and mechanical interlocking effect of the substrate surface, thereby restricting the level of substrate heterogeneous interface bonding force, and as the filling amount increases, the weakening effect increases. By adopting the method of the present invention, by depositing a modifier on the surface of the resin stacking film, the surface polar group density, quantity and adhesion of the substrate of the high-filling and ultra-high-filling system can be significantly improved, and the chemical bonding between the substrate and the metallic copper can be improved, thereby solving the problem of reduced substrate heterogeneous interface bonding force caused by high filler filling amount.

[0016] In some embodiments, the polymer resin is an epoxy-phenolic resin or an epoxy-cyanate resin. Epoxy-phenolic resin system substrates and epoxy-cyanate resin system substrates have a low degree of surface roughness and a low risk of copper plating during surface copper plating, making them suitable for large-scale substrate manufacturing.

[0017] In some embodiments, the method for preparing the resin substrate includes:

[0018] Fixing the two resin deposition films on the upper and lower surfaces of the core plate respectively, and then performing a heat pressing process at a temperature of 110-130° C. and a vacuum state of 0.5-0.7 MPa;

[0019] After hot pressing, the obtained samples were pre-cured at 100-120°C for 20-40 min and 180-200°C for 20-40 min in sequence;

[0020] After pre-curing, the sample surface is cleaned and then fluffed in a fluffing agent at 50-70°C for 5-20 minutes.

[0021] In some specific embodiments, the thermal compression temperature may be 110° C., 115° C., 120° C., 125° C., or 130° C. The thermal compression pressure may be 0.5 MPa, 0.55 MPa, 0.6 MPa, 0.65 MPa, or 0.7 MPa.

[0022] In some specific embodiments, a first pre-curing treatment may be performed at 100-120° C. for 20-40 minutes, and then a second pre-curing treatment may be performed at 180-200° C. for 20-40 minutes. The purpose of the pre-curing is to further cross-link and cure the resin deposition film.

[0023] In some specific embodiments, the temperature of the first pre-curing treatment may be 100° C., 105° C., 110° C., 115° C., or 120° C., and the time may be 20 min, 25 min, 30 min, 35 min, or 40 min.

[0024] In some specific embodiments, the temperature of the second pre-curing treatment may be 180° C., 185° C., 190° C., 195° C., or 200° C., and the time may be 20 min, 25 min, 30 min, 35 min, or 40 min.

[0025] In some specific embodiments, the temperature of the fluffing agent can be 50°C, 55°C, 60°C, 65°C, or 70°C. The fluffing time can be 5 minutes, 10 minutes, 15 minutes, or 20 minutes. The purpose of fluffing the resin substrate is to expose the silicon oxide filler in the resin deposited film to the film surface. This can increase the mechanical anchoring force between the film and the copper, enhance interfacial adhesion, and improve the bonding strength of the copper circuit.

[0026] In some embodiments, the cleaning process includes placing the sample in an alkaline solution to remove oil contamination, then ultrasonically washing the sample and drying the sample. The alkaline solution may be a sodium carbonate solution. Ultrasonic washing can remove surface impurities.

[0027] In some embodiments, the bulking agent is one or more of 2-(2-butoxyethoxy)ethanol, dimethylformamide, dihydroxy diethyl butyl ether, and ethylene glycol.

[0028] In some embodiments, after the deposition, the preparation method further comprises: cleaning the resin substrate; electroplating the surface of the resin substrate on which the polymer is deposited; baking; and curing. After the surface of the resin substrate is modified by the modifier, new polar groups such as hydroxyl, carboxyl and amino groups are generated, which increase the chemical bonding between the substrate and the copper plating and improve the interfacial bonding strength. It can be washed with water several times and blown dry after washing. The baking temperature can be 180-200°C, for example, 180°C, 185°C, 190°C, 195°C or 200°C. The baking time can be 30-90 min, for example, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min or 90 min.

[0029] In a second aspect, the present invention provides a surface chemically modified substrate obtained by the above-mentioned preparation method. The substrate of the present invention has a high interfacial bonding strength and meets the manufacturing requirements of large-scale substrates.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention provides a method for preparing a surface-chemically modified substrate. This method utilizes the ability of catechol-based modifiers, such as dihydroxyphenylalanine or dopamine, to self-polymerize and deposit on the surface of a resin substrate to achieve surface modification. After modification, new polar groups, such as hydroxyl, carboxyl, and amino groups, are generated on the substrate surface. These polar groups enhance the chemical bonding between the substrate and copper, improving interfacial adhesion. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Graphs showing the interface bonding force between the modified substrates prepared in Examples 1-3 and Comparative Example 1 and copper. DETAILED DESCRIPTION

[0033] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0034] Unless otherwise defined, the technical terms used in the following examples have the same meanings as commonly understood by those skilled in the art to which this invention belongs. The experimental reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the raw materials, instruments, and equipment used in the following examples are all commercially available or can be obtained through existing methods; the amounts of the experimental reagents used, unless otherwise specified, are the amounts used in conventional experimental procedures; and the experimental methods, unless otherwise specified, are all conventional methods.

[0035] Example 1

[0036] (1) Two epoxy-cyanate resin stacking films (purchased from Ajinomoto Co., Ltd., Japan) were fixed on the upper and lower sides of a core board (an epoxy resin composite material composed of epoxy resin and glass fiber, purchased from Shenzhen Liuxin Industrial Co., Ltd.), and then heat-pressed at 120°C and 0.6 MPa in vacuum;

[0037] (2) After lamination, the samples were pre-cured at 100°C for 30 min and 180°C for 30 min.

[0038] (3) After pre-curing, the sample was placed in a sodium carbonate solution to remove oil stains, and then ultrasonically washed and blown dry to complete the surface cleaning of the sample; then, the sample was fluffed in a fluffing agent (2-(2-butoxyethoxy)ethanol) at 60°C for 10 minutes;

[0039] (4) After fluffing, transfer to 80℃ potassium permanganate solution for oxidation treatment for 10 minutes;

[0040] (5) After oxidation, the substrate was placed in a dihydroxyphenylalanine (DOPA) aqueous solution at room temperature and pH 8.5 for chemical modification reaction for 2 h;

[0041] (6) After modification, the substrate was rinsed three times with deionized water and dried;

[0042] (7) After copper electroplating, the substrate was baked at 190°C for 60 minutes to remove moisture, and then cured at 190°C for 90 minutes to increase chemical crosslinking, thereby obtaining a surface chemically modified substrate.

[0043] Interface bonding strength test between modified substrate and copper:

[0044] (1) Cut the substrate into 60×13 mm strips for testing.

[0045] (2) Evenly peel off the copper sheet on the surface of the long sample from the substrate surface with a length of 15 mm;

[0046] (3) Use the lower fixture of the universal testing machine to keep the sample in a horizontal state;

[0047] (4) Fold the uncovered copper sheet along the unpeeled copper sheet into a shape 90° to the horizontal sample, and then fix the starting end of the uncovered copper sheet with the upper fixture of the universal testing machine;

[0048] (5) After fixing the sample, pull the copper sheet vertically upward at a tensile speed of 50 mm / min until the test stops automatically, and the peeling test is completed. Figure 1 As shown in .

[0049] Example 2

[0050] (1) Two epoxy-cyanate resin stacking films (purchased from Ajinomoto Co., Ltd., Japan) were fixed on the upper and lower sides of a core board (an epoxy resin composite material composed of epoxy resin and glass fiber, purchased from Shenzhen Liuxin Industrial Co., Ltd.), and then heat-pressed at 120°C and 0.6 MPa in vacuum;

[0051] (2) After lamination, the samples were pre-cured at 100°C for 30 min and 180°C for 30 min.

[0052] (3) After pre-curing, the sample was placed in a sodium carbonate solution to remove oil stains, and then ultrasonically washed and blown dry to complete the surface cleaning of the sample. The sample was then fluffed in a fluffing agent (2-(2-butoxyethoxy)ethanol) at 60°C for 10 min.

[0053] (4) After fluffing, transfer to 80℃ potassium permanganate solution for oxidation treatment for 10 minutes;

[0054] (5) After oxidation, the substrate was placed in a dihydroxyphenylalanine (DOPA) aqueous solution at room temperature and pH 8.5 for chemical modification reaction for 5 h;

[0055] (6) After modification, the substrate was rinsed three times with deionized water and dried;

[0056] (7) After copper electroplating, the substrate was baked at 190°C for 60 minutes to remove moisture, and then cured at 190°C for 90 minutes to increase chemical crosslinking, thereby obtaining a surface chemically modified substrate.

[0057] The interfacial bonding strength between the modified substrate and copper was tested according to the method of Example 1. The results are as follows: Figure 1 shown.

[0058] Example 3

[0059] (1) Two epoxy-cyanate resin stacking films (purchased from Ajinomoto Co., Ltd., Japan) were fixed on the upper and lower sides of a core board (an epoxy resin composite material composed of epoxy resin and glass fiber, purchased from Shenzhen Liuxin Industrial Co., Ltd.), and then heat-pressed at 120°C and 0.6 MPa in vacuum;

[0060] (2) After lamination, the samples were pre-cured at 100°C for 30 min and 180°C for 30 min.

[0061] (3) After pre-curing, the sample was placed in a sodium carbonate solution to remove oil stains, and then ultrasonically washed and blown dry to complete the surface cleaning of the sample. The sample was then fluffed in a fluffing agent (2-(2-butoxyethoxy)ethanol) at 60°C for 10 min.

[0062] (4) After fluffing, transfer to 80℃ potassium permanganate solution for oxidation treatment for 10 minutes;

[0063] (5) After oxidation, the substrate was placed in a dihydroxyphenylalanine (DOPA) aqueous solution at room temperature, pH 8.5, for chemical modification reaction for 10 h;

[0064] (6) After modification, the substrate was rinsed three times with deionized water and dried;

[0065] (7) After copper electroplating, the substrate was baked at 190°C for 60 minutes to remove moisture, and then cured at 190°C for 90 minutes to increase chemical crosslinking, thereby obtaining a surface chemically modified substrate.

[0066] The interfacial bonding strength between the modified substrate and copper was tested according to the method of Example 1. The results are as follows: Figure 1 shown.

[0067] Example 4

[0068] (1) Two epoxy-cyanate resin stacking films (purchased from Ajinomoto Co., Ltd., Japan) were fixed on the upper and lower sides of a core board (an epoxy resin composite material composed of epoxy resin and glass fiber, purchased from Shenzhen Liuxin Industrial Co., Ltd.), and then heat-pressed at 120°C and 0.6 MPa in vacuum;

[0069] (2) After lamination, the samples were pre-cured at 100°C for 30 min and 180°C for 30 min.

[0070] (3) After pre-curing, the sample was placed in a sodium carbonate solution to remove oil stains, and then ultrasonically washed and blown dry to complete the surface cleaning of the sample. The sample was then fluffed in a fluffing agent (2-(2-butoxyethoxy)ethanol) at 60°C for 10 min.

[0071] (4) After fluffing, transfer to 80℃ potassium permanganate solution for oxidation treatment for 10 minutes;

[0072] (5) After oxidation, the substrate was placed in a dihydroxyphenylalanine (DOPA) aqueous solution at room temperature, pH 8.5, for chemical modification reaction for 10 min;

[0073] (6) After modification, the substrate was rinsed three times with deionized water and dried;

[0074] (7) After copper electroplating, the substrate was baked at 190°C for 60 minutes to remove moisture, and then cured at 190°C for 90 minutes to increase chemical crosslinking, thereby obtaining a surface chemically modified substrate.

[0075] The interfacial bonding strength between the modified substrate and copper was tested according to the method of Example 1, and the results obtained were similar to those of Example 1.

[0076] Example 5

[0077] (1) Two epoxy-cyanate resin stacking films (purchased from Ajinomoto Co., Ltd., Japan) were fixed on the upper and lower sides of a core board (an epoxy resin composite material composed of epoxy resin and glass fiber, purchased from Shenzhen Liuxin Industrial Co., Ltd.), and then heat-pressed at 110°C and 0.7 MPa in vacuum;

[0078] (2) After lamination, the samples were pre-cured at 110°C for 40 min and 190°C for 40 min.

[0079] (3) After pre-curing, the sample was placed in a sodium carbonate solution to remove oil stains, and then ultrasonically washed and blown dry to complete the surface cleaning of the sample. The sample was then fluffed in a fluffing agent (2-(2-butoxyethoxy)ethanol) at 50°C for 20 minutes.

[0080] (4) After fluffing, transfer to a 70°C potassium permanganate solution for oxidation treatment for 15 minutes;

[0081] (5) After oxidation, the substrate was placed in a dihydroxyphenylalanine (DOPA) aqueous solution at room temperature, pH 8.5, for chemical modification reaction for 10 min;

[0082] (6) After modification, the substrate was rinsed three times with deionized water and dried;

[0083] (7) After copper electroplating, the substrate was baked at 190°C for 60 minutes to remove moisture, and then cured at 190°C for 90 minutes to increase chemical crosslinking, thereby obtaining a surface chemically modified substrate.

[0084] The interfacial bonding strength between the modified substrate and copper was tested according to the method of Example 1, and the results obtained were similar to those of Example 1.

[0085] Example 6

[0086] (1) Two epoxy-cyanate resin stacking films (purchased from Ajinomoto Co., Ltd., Japan) were fixed on the upper and lower sides of a core board (an epoxy resin composite material composed of epoxy resin and glass fiber, purchased from Shenzhen Liuxin Industrial Co., Ltd.), and then heat-pressed at 130°C and 0.5 MPa in vacuum;

[0087] (2) After lamination, the samples were pre-cured at 120°C for 20 min and 200°C for 20 min.

[0088] (3) After pre-curing, the sample was placed in a sodium carbonate solution to remove oil stains, and then ultrasonically washed and blown dry to complete the surface cleaning of the sample. The sample was then fluffed in a fluffing agent (2-(2-butoxyethoxy)ethanol) at 70°C for 5 minutes.

[0089] (4) After fluffing, transfer to a 90°C potassium permanganate solution for oxidation treatment for 5 minutes;

[0090] (5) After oxidation, the substrate was placed in a dihydroxyphenylalanine (DOPA) aqueous solution at room temperature, pH 8.5, for chemical modification reaction for 10 min;

[0091] (6) After modification, the substrate was rinsed three times with deionized water and dried;

[0092] (7) After copper electroplating, the substrate was baked at 190°C for 60 minutes to remove moisture, and then cured at 190°C for 90 minutes to increase chemical crosslinking, thereby obtaining a surface chemically modified substrate.

[0093] The interfacial bonding strength between the modified substrate and copper was tested according to the method of Example 1, and the results obtained were similar to those of Example 1.

[0094] Comparative Example 1

[0095] The method of Example 1 was followed, except that step (5) was not performed.

[0096] The interfacial bonding strength between the modified substrate and copper was tested according to the method of Example 1. The results are as follows: Figure 1 As shown (i.e., the curve represented by the control sample).

[0097] The foregoing description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be readily conceived by a person skilled in the art within the technical scope disclosed herein are intended to be encompassed within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A method for preparing a surface chemically modified substrate, characterized in that: The following steps are involved: placing a resin substrate in a catechol monomer solution to allow the catechol monomer to undergo a self-polymerization reaction, and the generated polymer is deposited on the surface of the resin substrate; Wherein, the catechol monomer is dihydroxyphenylalanine or dopamine.

2. The preparation method according to claim 1, characterized in that The pH value of the catechol monomer solution is 8-9; the time of the self-polymerization reaction is 5 minutes to 10 hours; the catechol monomer solution is an aqueous solution of catechol monomers.

3. The preparation method according to claim 1 or 2, characterized in that Before placing the resin substrate in the catechol monomer solution, the preparation method further comprises: placing the resin substrate in an oxidant solution for oxidation treatment.

4. The preparation method according to claim 3, characterized in that The oxidant is one or more of potassium permanganate, hydrogen peroxide, peracetic acid, sodium dichromate, chromic acid, nitric acid, ammonium persulfate, sodium hypochlorite, sodium percarbonate, sodium perborate, and potassium perborate; the oxidation temperature is 70-90° C.; and the oxidation time is 5-15 minutes.

5. The preparation method according to claim 1 or 2, characterized in that The resin substrate includes a core plate and a resin deposition film arranged on the upper and lower surfaces of the core plate; the material of the resin deposition film is a mixture of polymer resin and silica filler; the core plate is a silicon substrate, a ceramic substrate, a glass substrate or an epoxy resin composite material composed of epoxy resin and glass fiber.

6. The preparation method according to claim 5, characterized in that The polymer resin is epoxy-phenolic resin or epoxy-cyanate resin.

7. The preparation method according to claim 5, characterized in that The method for preparing the resin substrate comprises: Fixing the two resin deposition films on the upper and lower surfaces of the core plate respectively, and then performing a heat pressing process at a temperature of 110-130° C. and a vacuum state of 0.5-0.7 MPa; After hot pressing, the obtained samples were pre-cured at 100-120°C for 20-40 min and 180-200°C for 20-40 min in sequence; After pre-curing, the sample surface is cleaned and then fluffed in a fluffing agent at 50-70°C for 5-20 minutes.

8. The preparation method according to claim 7, characterized in that The cleaning process includes: placing the sample in an alkaline solution to remove oil stains, then ultrasonically washing and drying; The bulking agent is one or more of 2-(2-butoxyethoxy)ethanol, dimethylformamide, dihydroxy diethyl butyl ether, and ethylene glycol.

9. The preparation method according to claim 1 or 2, characterized in that: After the deposition, the preparation method further comprises: cleaning the resin substrate; electroplating the surface of the resin substrate on which the polymer is deposited; baking; and curing.

10. A surface chemically modified substrate, characterized in that: The method is obtained by the preparation method according to any one of claims 1 to 9.

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