MSAP processing technology of similar support plate

Abstract

The invention relates to the technical field of semiconductor packaging, in particular to a carrier-like MSAP processing technology, which comprises the following steps of: selecting a copper foil as a starting material, cleaning and activating the surface of the copper foil, immersing the copper foil into a specially-made browning liquid medicine, controlling the reaction time and temperature, uniformly thinning the copper foil to 4 microns, taking out the copper foil from the browning liquid medicine, cleaning and drying, and carrying out vacuum drying on the copper foil to obtain the carrier-like MSAP. The method comprises the following steps of: uniformly coating a layer of photoresist on a thinned copper foil, exposing the photoresist by using a specific photomask, performing developing treatment to form a required circuit pattern, electroplating a region which is not protected by the photoresist, forming a conductive path, removing the residual photoresist in a laser manner, and removing the redundant copper foil by using an etching agent to form a circuit pattern. According to the method for thinning the copper foil to about 4 microns by using the brownification liquid medicine, the carrier copper foil with the thickness of 18 + 3 microns manufactured by the traditional technology can be effectively replaced, so that the problems of thick carrier copper foil and high price in the prior art are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor packaging, and in particular to a carrier-like MSAP processing technology. Background Art

[0002] In the manufacturing of SLP substrates, the traditional semi-additive copper foil (MSAP) process typically uses an 18+3μm thick copper foil. This process requires attaching a 3μm thick copper foil to the 18μm thick copper foil. The 18μm thick copper foil is then removed and discarded before drilling, leaving only the 3μm thick foil for subsequent processing. This method not only increases production costs, but also, as the main supplier is Japanese companies, the carrier copper foil is largely imported, further exacerbating the cost problem.

[0003] To address the above issues, the present invention proposes a new method, using a browning solution to thin the copper foil to approximately 4μm, replacing the traditional 18+3μm thick carrier copper foil. The advantages of this method include: reduced costs, as the 18μm thick carrier copper layer is not required, conventional copper foil can be used instead, significantly reducing material costs; simplified production processes, eliminating the step of removing the 18μm thick carrier copper, streamlining the production process and improving production efficiency; improved quality, as the new method can more accurately control the thickness of the copper foil, helping to improve the quality stability of the final product; and reduced dependence on imported carrier copper foil, reducing supply chain risks.

[0004] This innovative method not only reduces the production cost of SLP-type substrates, but also improves production efficiency and product quality, which is of great significance for promoting the development of the electronics industry. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the present invention provides a carrier-like MSAP processing technology, which has the advantages of thin carrier copper foil and low price, and solves the problem of thick carrier copper foil and high price in the existing technology.

[0006] To achieve the above-mentioned object, the present invention provides the following technical solution: a carrier-like MSAP processing technology, comprising the following process steps: Step 1. Material preparation: Choose copper foil as the starting material; Step 2: Surface treatment: Clean and activate the copper foil surface; Step 3: Browning solution treatment: Immerse the copper foil in a special browning solution, control the reaction time and temperature, and uniformly thin the copper foil to 4μm; Step 4: Cleaning and drying: Remove the copper foil from the browning solution, clean it, and then dry it in an oven; Step 5: Photoresist coating: evenly coat a layer of photoresist on the thinned copper foil; Step 6: Exposure and development: Use a specific photomask to expose the photoresist, and then develop it to form the desired circuit pattern; Step 7: Electroplating: Electroplating is performed on the areas not protected by the photoresist to form a conductive path; Step 8: Remove the photoresist: remove the remaining photoresist by laser; Step 9: Etching: Use an etchant to remove excess copper foil, leaving behind the circuit pattern. Step 10: Cleaning and Inspection: After etching is completed, the PCB is cleaned and quality inspected.

[0007] Preferably, the activation treatment process of the copper foil surface in step 2 is as follows: placing the copper foil in a colloidal palladium activation solution and performing a reaction at a temperature of 20-30° C. for 8-15 minutes. The chemical reaction equation is: Pd 2+ +2SnCl2+4HCl→Pd+2SnCl4+2H2+Sn; In the reaction formula, Pd 2+ represents the palladium ion in palladium chloride, SnCl2 represents stannous chloride, and HCl represents hydrochloric acid. During the reaction, palladium ions are reduced to metallic palladium, and stannous chloride is oxidized to tin tetrachloride. At the same time, part of the stannous chloride will react with hydrochloric acid to generate hydrogen chloride and hydrogen, as well as metallic tin.

[0008] Preferably, the components and proportions of the browning solution are: 1.12% to 1.51% silane coupling agent; 2.16% to 2.22% benzotriazole; 5.20% to 6.00% hydrogen peroxide; 3.08% to 3.34% glycolic acid; 1.04% to 1.20% zinc nitrate; 4.26% to 4.66% thioglycolic acid; 0.66% to 0.80% 2-mercaptobenzothiazole; 0.91% to 1.02% tolutriazole; 5.44% to 5.72% anhydrous copper sulfate; and 4.07% to 4.52% hydrochloric acid.

[0009] Preferably, the preparation process of the browning solution is as follows: prepare standard reagents with the same composition ratio, mix them evenly with a glass stirring rod at a temperature of 5-10° C., and the browning solution is prepared.

[0010] Preferably, the browning solution is used by diluting the browning solution with pure water in a weight ratio of 1:5.

[0011] Preferably, in the step 5, the photoresist is selected by selecting positive photoresist and deep ultraviolet photoresist, applying the positive photoresist on the surface with a thickness of 0.4-0.8 mm, and after drying, applying deep ultraviolet photoresist on the surface with a thickness of 0.2-0.5 mm.

[0012] Preferably, the exposure process of the specific photomask is as follows: using a deep ultraviolet mask to expose the photoresist under a high-intensity ultraviolet light source for 5-10 seconds.

[0013] Preferably, the electroplating conditions in step seven are set as follows: current density is 1-5 A / dm², temperature is 45-60° C., and duration is 0.5-1 h.

[0014] Preferably, in step eight, the photoresist is removed by irradiating and evaporating the photoresist with a laser having a power of 60 watts to remove the remaining photoresist.

[0015] Preferably, the etching process in step nine is as follows: selecting ammonium sulfate with a concentration of 20% to 30% as the etchant, controlling the reaction temperature at 45-50° C., and controlling the reaction time at 3-5 minutes. The reaction chemical equation is: Cu+(NH4)2SO4→CuSO4+2NH3+H2O; In the reaction formula, copper reacts with ammonium sulfate solution to produce copper sulfate, ammonia gas and water.

[0016] Compared with the prior art, the present invention provides a carrier-like MSAP processing technology with the following beneficial effects: 1. The present invention uses a novel method to thin copper foil to approximately 4 μm by using a browning solution with a specific formula ratio. This method can effectively replace the 18+3 μm thick carrier copper foil manufactured using traditional technology for use in the semi-additive process (MSAP). It also eliminates the need for an 18 μm thick carrier copper layer, reducing the price of conventional copper foil and, consequently, the cost of SLP-type carrier boards. This improvement not only improves processing time but also reduces processing costs, thereby resolving the problem of thick and expensive carrier copper foil in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a step diagram of the method of the present invention. DETAILED DESCRIPTION

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0019] See also Figure 1 , a substrate-like MSAP process, including the following process steps: Step 1: Material preparation: Choose copper foil as the starting material. Copper foil is easy to process into the required shape and thickness, which is convenient for subsequent processing. Step 2: Surface treatment: Clean and activate the copper foil surface to ensure good adhesion; Step 3: Browning solution treatment: Immerse the copper foil in a special browning solution, control the reaction time and temperature, and uniformly thin the copper foil to 4μm. By controlling the reaction time and temperature, the copper foil can be uniformly thinned to 4μm. Thinner copper foil helps improve circuit performance, such as reducing signal delay and improving frequency response. Step 4: Cleaning and Drying: Remove the copper foil from the browning solution, clean it thoroughly, and then dry it in an oven. Thorough cleaning can remove the residue in the browning solution to prevent it from affecting the results of subsequent processes. The drying process can prevent oxidation on the copper foil surface and maintain its good conductive properties. Step 5: Photoresist coating: A layer of photoresist is evenly coated on the thinned copper foil. The photoresist can serve as a protective layer to protect the unexposed areas from the effects of the etchant, and through photolithography technology, the circuit pattern on the photomask can be accurately transferred to the photoresist; Step 6: Exposure and Development: Use a specific photomask to expose the photoresist, and then develop it to form the required circuit pattern. The exposure and development process can form a high-precision circuit pattern to meet the needs of fine circuits; Step 7: Electroplating: Electroplating is performed on the areas not protected by the photoresist to form a conductive path. The electroplating layer can enhance the conductivity and improve the performance of the circuit. Step 8: Remove the photoresist: Use laser to remove the remaining photoresist. Laser photoresist removal can accurately control the removal area to avoid damaging the circuit pattern. Step 9, Etching: Use an etchant to remove excess copper foil, leaving the circuit pattern. The etching process can remove excess copper foil and leave the desired circuit pattern. Step 10. Cleaning and Inspection: After etching is completed, the PCB is thoroughly cleaned and quality inspected. Thorough cleaning can remove the residues generated during the etching process and ensure the cleanliness of the PCB.

[0020] Step 2: Activation of the copper foil surface: Place the copper foil in a colloidal palladium activation solution and allow the reaction to proceed for 8-15 minutes at a temperature of 20-30°C. The chemical reaction equation is: Pd 2+ +2SnCl2+4HCl→Pd+2SnCl4+2H2+Sn; In the reaction formula, Pd2+ represents the palladium ion in palladium chloride, SnCl2 represents stannous chloride, and HCl represents hydrochloric acid. During the reaction, palladium ions are reduced to metallic palladium (Pd), and stannous chloride is oxidized to tin tetrachloride (SnCl4). At the same time, part of the stannous chloride will react with hydrochloric acid to generate hydrogen chloride (HCl) and hydrogen (H2), as well as metallic tin (Sn).

[0021] The ingredients and proportions of the browning solution are: silane coupling agent 1.12%~1.51%; benzotriazole 2.16%~2.22%; hydrogen peroxide 5.20%~6.00%; glycolic acid 3.08%~3.34%; zinc nitrate 1.04%~1.20%; thioglycolic acid 4.26%~4.66%; 2-mercaptobenzothiazole 0.66%~0.80%; methylbenzotriazole 0.91%~1.02%; anhydrous copper sulfate 5.44%~5.72%; hydrochloric acid 4.07%~4.52%.

[0022] The browning solution is prepared by preparing the standard reagents at a ratio of 5-10°C using a glass stirring rod. Mixing at a low temperature of 5-10°C helps control the reaction rate and ensures uniform mixing of the components, avoiding uneven composition caused by local overheating or overcooling. Using a glass stirring rod prevents the introduction of impurities and maintains the purity of the solution.

[0023] Use of browning solution: Dilute the browning solution with pure water at a ratio of 1:5 by weight to ensure uniform thinning of the copper foil without damaging the substrate. By diluting it with pure water at a ratio of 1:5, the concentration of the solution can be reduced, reducing the risk of corrosion to the copper foil substrate while ensuring uniform thinning of the copper foil. This specific dilution method is both economical and environmentally friendly.

[0024] Selection of photoresist in step five: Select positive photoresist and deep ultraviolet photoresist, apply positive photoresist on the surface with a thickness of 0.4-0.8mm. After drying, apply deep ultraviolet photoresist on the surface with a thickness of 0.2-0.5mm, thereby increasing its resolution, adhesion and chemical resistance, improving the accuracy of pattern transfer, and reducing light sensitivity. The combination of positive photoresist and deep ultraviolet photoresist can form a thicker protective layer on the surface, improve resolution and adhesion, and deep ultraviolet photoresist has better chemical resistance, which can reduce light sensitivity and improve the accuracy of pattern transfer.

[0025] The exposure process of a specific photomask: Use a deep ultraviolet (DUV) photomask to expose the photoresist under a high-intensity ultraviolet light source for 5-10 seconds. Using a deep ultraviolet (DUV) photomask for exposure under a high-intensity ultraviolet light source can shorten the exposure time and improve production efficiency. The exposure time of 5-10 seconds can ensure that the photoresist is fully cured to form a clear circuit pattern.

[0026] The electroplating conditions in step seven are set as follows: current density of 1-5A / dm², temperature of 45-60℃, and duration of 0.5-1h to ensure the uniformity and conductivity of the circuit. The electroplating conditions of current density of 1-5A / dm², temperature of 45-60℃, and duration of 0.5-1h can ensure the uniformity and conductivity of the electroplating layer. Appropriate current density and temperature can also improve electroplating efficiency and shorten the processing cycle.

[0027] Removing the photoresist in step eight: Using a 60-watt laser to irradiate and evaporate the photoresist to remove the remaining photoresist. Using a 60-watt laser to irradiate and evaporate the photoresist can quickly and efficiently remove the remaining photoresist and avoid damaging the substrate. This method helps improve processing efficiency and reduce costs.

[0028] The etching process in step nine is as follows: select 20% to 30% concentration of ammonium sulfate as the etchant, control the reaction temperature at 45-50°C, and control the reaction time at 3-5 minutes. The reaction chemical equation is: Cu+(NH4)2SO4→CuSO4+2NH3+H2O; In the reaction formula, copper reacts with ammonium sulfate solution to generate copper sulfate, ammonia gas, and water. Etching under these conditions can avoid circuit breakage caused by over-etching or short circuit caused by insufficient etching. Example

[0029] The ingredients and proportions of the browning solution are: 1.12% silane coupling agent; 2.16% benzotriazole; 5.55% hydrogen peroxide; 3.24% glycolic acid; 1.10% zinc nitrate; 4.36% thioglycolic acid; 0.68% 2-mercaptobenzothiazole; 0.98% methylbenzotriazole; 5.50% anhydrous copper sulfate; and 4.47% hydrochloric acid. Example

[0030] The ingredients and proportions of the browning solution are: 1.51% silane coupling agent; 2.22% benzotriazole; 6.00% hydrogen peroxide; 3.34% glycolic acid; 1.20% zinc nitrate; 4.66% thioglycolic acid; 0.80% 2-mercaptobenzothiazole; 1.02% methylbenzotriazole; 5.72% anhydrous copper sulfate; and 4.52% hydrochloric acid. Example

[0031] The ingredients and proportions of the browning solution are: 1.19% silane coupling agent; 2.19% benzotriazole; 5.40% hydrogen peroxide; 3.14% glycolic acid; 1.10% zinc nitrate; 4.46% thioglycolic acid; 0.70% 2-mercaptobenzothiazole; 1.00% methylbenzotriazole; 5.62% anhydrous copper sulfate; and 4.42% hydrochloric acid.

[0032] Comparative Example 1 The ingredients and proportions of the browning solution are: silane coupling agent 0.98%; benzotriazole 2.01%; hydrogen peroxide 4.55%; glycolic acid 2.44%; zinc nitrate 0.81%; thioglycolic acid 3.56%; 2-mercaptobenzothiazole 0.48%; methylbenzotriazole 0.88%; anhydrous copper sulfate 5.00%; and hydrochloric acid 4.37%.

[0033] Comparative Example 2 The ingredients and proportions of the browning solution are: 1.71% silane coupling agent; 3.22% benzotriazole; 7.00% hydrogen peroxide; 4.34% glycolic acid; 2.20% zinc nitrate; 5.06% thioglycolic acid; 1.80% 2-mercaptobenzothiazole; 1.42% methylbenzotriazole; 5.92% anhydrous copper sulfate; and 5.52% hydrochloric acid.

[0034] Comparative Example 3 The ingredients and proportions of the browning solution are: 0.12% silane coupling agent; 3.19% benzotriazole; 5.40% hydrogen peroxide; 1.14% glycolic acid; 1.10% zinc nitrate; 5.46% thioglycolic acid; 0.70% 2-mercaptobenzothiazole; 1.00% methylbenzotriazole; 5.62% anhydrous copper sulfate; and 5.42% hydrochloric acid.

[0035] Ingredient Comparison Table 1 Element Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Silane coupling agent (%) 1.12 1.51 1.19 0.98 1.71 0.12 Benzotriazole (%) 2.16 2.22 2.19 2.01 3.22 3.19 Hydrogen peroxide (%) 5.55 6.00 5.40 4.55 7.00 5.40 Glycolic acid (%) 3.24 3.34 3.14 2.44 4.34 1.14 Zinc nitrate (%) 1.10 1.20 1.10 0.81 2.20 1.10 Thioglycolic acid (%) 4.36 4.66 4.46 3.56 5.06 5.46 2-Mercaptobenzothiazole(%) 0.68 0.80 0.70 0.48 1.8 0.70 Methylbenzotriazole (%) 0.98 1.02 1.00 0.88 1.42 1.00 Anhydrous copper sulfate (%) 5.50 5.72 5.62 5.00 5.92 5.62 hydrochloric acid(%) 4.47 4.52 4.42 4.37 5.52 5.42 The browning solutions prepared in Examples 1 and 3, and Comparative Examples 1 and 3, were used in the method of the present invention. The substrates processed with the browning solutions were then tested for thickness (μm), peel strength (N / mm), thermal shock resistance (pass / fail), and microetching (μm). The data are shown in Table 2 below: Table 2 Comparison of performance indicators of browning solution formula Case / Test Project Thickness (μm) Peel strength (N / mm) Thermal shock resistance Micro-etching amount (μm) Cost of browning solution (compared with traditional process) Example 1 3.99 1.2 pass 0.5 down 0.95% Example 2 4.00 1.1 pass 0.4 down 0.5% Example 3 4.01 0.9 pass 0.3 down 1.5% Example 1 13 0.9 fail 0.3 down 0.8% Example 2 13 0.9 fail 0.3 down 1.15% Example 3 9 0.6 fail 0.2 down 0.1% Note: 3.95μm≤standard thickness (μm)≤4.05μm; From Tables 1 and 2, we can get the following information: The browning solution formulations of Examples 1, 2, and 3 all exhibited good performance in terms of thickness, peel strength, thermal shock resistance, and micro-etching. The carrier-like boards of the Examples all had a thickness of approximately 4 μm, a peel strength between 0.9 and 1.2 N / mm, passed the thermal shock resistance test, and had micro-etching amounts of 0.3 to 0.5 μm. In comparison, the carrier-like boards of Comparative Examples 1 and 3 performed poorly in terms of performance indicators of thickness (μm), peel strength (N / mm), thermal shock resistance (pass / fail), and micro-etching amount (μm), especially failing the thermal shock resistance test. Furthermore, their thicknesses were all between 9 and 13 μm, failing to meet the standard thickness indicators. This indicates that the changes in the components and proportions of the comparative examples exceeded the specific gravity range of the formulation of the present invention, resulting in deterioration of the above-mentioned properties. Furthermore, the cost of the browning solution in the Examples and Comparative Examples decreased compared to the traditional process, with a decrease of between 0.1% and 1.5%.

[0036] The above results show that the new method of thinning copper foil to about 4μm using the browning solution with a formula ratio used in the present invention can effectively replace the 18+3μm thick carrier copper foil manufactured by traditional technology for use in the semi-additive MSAP process, and does not require the use of an 18μm thick carrier copper layer, thereby reducing the price of conventional copper foil and thus reducing the cost of SLP-type carrier boards. This improvement not only improves processing time but also reduces processing costs, thereby solving the problem of thick and expensive carrier copper foil in the prior art.

[0037] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A carrier-like MSAP processing technology, characterized in that: The process steps include: Step 1. Material preparation: Choose copper foil as the starting material; Step 2: Surface treatment: Clean and activate the copper foil surface; Step 3: Browning solution treatment: Immerse the copper foil in a special browning solution, control the reaction time and temperature, and uniformly thin the copper foil to 4μm; Step 4: Cleaning and drying: Remove the copper foil from the browning solution, clean it, and then dry it in an oven; Step 5: Photoresist coating: evenly coat a layer of photoresist on the thinned copper foil; Step 6: Exposure and development: Use a specific photomask to expose the photoresist, and then develop it to form the desired circuit pattern; Step 7: Electroplating: Electroplating is performed on the areas not protected by the photoresist to form a conductive path; Step 8: Remove the photoresist: remove the remaining photoresist by laser; Step 9: Etching: Use an etchant to remove excess copper foil, leaving behind the circuit pattern. Step 10: Cleaning and Inspection: After etching, the PCB is cleaned and quality inspected. The composition and proportion of the browning solution are as follows: 1.12% to 1.51% silane coupling agent; 2.16% to 2.22% benzotriazole; 5.20% to 6.00% hydrogen peroxide; 3.08% to 3.34% glycolic acid; 1.04% to 1.20% zinc nitrate; 4.26% to 4.66% thioglycolic acid; 0.66% to 0.80% 2-mercaptobenzothiazole; 0.91% to 1.02% tolyltriazole; 5.44% to 5.72% anhydrous copper sulfate; 4.07% to 4.52% hydrochloric acid; The exposure process of the specific photomask is as follows: using a deep ultraviolet mask to expose the photoresist under a high-intensity ultraviolet light source for 5-10 seconds.

2. The MSAP processing technology for a carrier-like substrate according to claim 1, characterized in that: The activation treatment process of the copper foil surface in step 2 is as follows: placing the copper foil in colloidal palladium activation solution and reacting at a temperature of 20-30° C. for 8-15 minutes. The chemical reaction equation is: Pd 2+ +2SnCl2+4HCl→Pd+2SnCl4+2H2+Sn ； In the reaction formula, Pd 2+ represents the palladium ion in palladium chloride, SnCl2 represents stannous chloride, and HCl represents hydrochloric acid. During the reaction, palladium ions are reduced to metallic palladium, and stannous chloride is oxidized to tin tetrachloride. At the same time, part of the stannous chloride will react with hydrochloric acid to generate hydrogen chloride and hydrogen, as well as metallic tin.

3. The MSAP processing technology for a carrier-like substrate according to claim 1, characterized in that: The preparation process of the browning solution is as follows: prepare standard reagents with the same composition ratio, mix them evenly with a glass stirring rod at a temperature of 5-10° C., and the browning solution is prepared.

4. The MSAP processing technology for a carrier-like substrate according to claim 3, characterized in that: The use of the browning solution: dilute the browning solution with pure water in a ratio of 1:5 by weight.

5. The MSAP processing technology for a carrier-like substrate according to claim 1, characterized in that: The selection of photoresist in the step 5: select positive photoresist and deep ultraviolet photoresist, apply positive photoresist on the surface with a thickness of 0.4-0.8mm, and after drying, apply deep ultraviolet photoresist on the surface with a thickness of 0.2-0.5mm.

6. The MSAP processing technology for a carrier-like substrate according to claim 1, characterized in that: The electroplating conditions in step seven are as follows: current density of 1-5 A / dm², temperature of 45-60°C, and duration of 0.5-1 h.

7. The MSAP processing technology for a carrier-like substrate according to claim 1, characterized in that: In the step eight, the photoresist is removed by irradiating and evaporating the photoresist with a laser having a power of 60 watts to remove the remaining photoresist.

8. The MSAP processing technology for a carrier-like substrate according to claim 1, characterized in that: The etching process in step nine is as follows: 20% to 30% ammonium sulfate is selected as the etchant, the reaction temperature is controlled at 45-50°C, and the reaction time is controlled at 3-5 minutes. The reaction chemical equation is: Cu+(NH4)2SO4→CuSO4+2NH3+H2O; In the reaction formula, copper reacts with ammonium sulfate solution to produce copper sulfate, ammonia gas and water.

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