A kind of MSAP processing technology of carrier-like board

Abstract

The application relates to the technical field of semiconductor packaging and relates to a kind of MSAP processing technology of carrier-like, copper foil is selected as starting material, the surface of copper foil is cleaned and activated, copper foil is immersed in special brown liquor, reaction time and temperature are controlled, copper foil is uniformly thinned to 4 mu m, copper foil is taken out from brown liquor, after washing and drying, a layer of photoresist is uniformly coated on the thinned copper foil, specific photomask is used to expose photoresist, then development treatment is carried out, the required circuit pattern is formed, electroplating is carried out in the area not protected by photoresist, conductive path is formed, remaining photoresist is removed by laser, and etchant is used to remove excess copper foil, leaving circuit pattern, the application can effectively replace the 18+3 mu m thick carrier copper foil manufactured by traditional technology by using brown liquor to thin copper foil to about 4 mu m, thereby solving the problems of thick carrier copper foil and high price in the prior art.

Description

Technical Field

[0001] This invention relates to the field of semiconductor packaging technology, specifically to a substrate-like MSAP processing technology. Background Technology

[0002] In the manufacturing process of SLP-type substrates, the traditional semi-additive MSAP process typically uses a 18μm+3μm thick carrier copper foil. This process requires attaching a 3μm thick copper foil layer onto an 18μm thick carrier copper layer, then peeling off and discarding the 18μm thick carrier copper layer before drilling, retaining only the 3μm thick copper foil for subsequent processing. This method not only increases production costs, but also, because the main supplier is a Japanese company, leads to a heavy reliance on imported carrier copper foil, further exacerbating the cost problem.

[0003] To address the above issues, this invention proposes a novel method: using a browning agent to thin the copper foil to approximately 4μm, replacing the traditional 18+3μm thick carrier copper foil. The advantages of this method are: reduced cost, as the 18μm thick carrier copper layer is unnecessary and conventional copper foil can be used, significantly reducing material costs; simplified process, eliminating the step of removing the 18μm thick carrier copper, simplifying the production process and improving efficiency; improved quality, as the new method allows for more precise control of the copper foil thickness, contributing to improved final product quality stability; and reduced dependence, eliminating reliance on imported carrier copper foil, thus reducing supply chain risks.

[0004] This innovative approach not only reduces the production cost of SLP 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] To address the shortcomings of existing technologies, this invention provides a substrate-like MSAP processing technology that features thin and low-cost carrier copper foil, thus solving the problems of thick and expensive carrier copper foil in existing technologies.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a substrate-like MSAP processing technology, comprising the following process steps:

[0007] Step 1: Material Preparation: Select copper foil as the starting material;

[0008] Step 2, Surface Treatment: Clean and activate the surface of the copper foil;

[0009] Step 3, Browning treatment: Immerse the copper foil in a specially prepared browning solution, control the reaction time and temperature, and make the copper foil uniformly thin to 4μm;

[0010] Step 4, Cleaning and Drying: Remove the copper foil from the browning solution, clean it, and then dry it in an oven;

[0011] Step 5, Photoresist Coating: A layer of photoresist is uniformly coated onto the thinned copper foil;

[0012] Step 6, Exposure and Development: The photoresist is exposed using a specific photomask and then developed to form the desired circuit pattern.

[0013] Step 7, Electroplating: Electroplating is performed on the areas not protected by photoresist to form conductive paths;

[0014] Step 8: Remove photoresist: Remove the remaining photoresist using a laser.

[0015] Step 9, Etching: Use an etchant to remove excess copper foil, leaving the circuit pattern;

[0016] Step 10, Cleaning and Inspection: After etching, the resulting PCB is cleaned and subjected to quality inspection.

[0017] Preferably, the activation process of the copper foil surface in step two is as follows: the copper foil is placed in a colloidal palladium activation solution and reacted at a temperature of 20-30°C for 8-15 minutes. The chemical reaction equation is as follows:

[0018] Pd 2+ +2SnCl2+4HCl→Pd+2SnCl4+2H2+Sn;

[0019] In the reaction formula, Pd 2+ The symbol 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, while stannous chloride is oxidized to stannous tetrachloride. At the same time, some stannous chloride reacts with hydrochloric acid to produce hydrogen chloride and hydrogen gas, as well as metallic tin.

[0020] Preferably, the composition and proportions of the browning solution are as follows: 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%; mercaptoacetic acid 4.26%–4.66%; 2-mercaptobenzothiazole 0.66%–0.80%; methyltriazole 0.91%–1.02%; anhydrous copper sulfate 5.44%–5.72%; hydrochloric acid 4.07%–4.52%.

[0021] Preferably, the preparation process of the browning solution is as follows: prepare standard reagents with the specified component ratios, mix them evenly using a glass stirring rod at a temperature of 5-10°C, and the browning solution is prepared.

[0022] Preferably, the browning agent is used by diluting it with pure water at a ratio of 1:5 by weight.

[0023] Preferably, in step five, the photoresist is selected as follows: positive photoresist and deep ultraviolet photoresist are selected. The positive photoresist is applied to the surface with a thickness of 0.4-0.8 mm. After drying, the deep ultraviolet photoresist is applied to the surface with a thickness of 0.2-0.5 mm.

[0024] Preferably, the exposure process of the specific photomask is as follows: the photoresist is exposed for 5-10 seconds using a deep ultraviolet photomask under a high-intensity ultraviolet light source.

[0025] Preferably, the electroplating conditions in step seven are set as follows: current density of 1-5 A / dm², temperature of 45-60℃, and duration of 0.5-1 h.

[0026] Preferably, in step eight, the photoresist is removed by irradiating and evaporating the photoresist with a laser with a power of 60 watts to remove the remaining photoresist.

[0027] Preferably, the etching process in step nine is as follows: ammonium sulfate with a concentration of 20%–30% 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 chemical equation for the reaction is:

[0028] Cu+(NH4)2SO4→CuSO4+2NH3+H2O;

[0029] In the reaction equation, copper reacts with ammonium sulfate solution to produce copper sulfate, ammonia, and water.

[0030] Compared with the prior art, the present invention provides a substrate-like MSAP processing technology, which has the following advantages:

[0031] 1. This invention provides a novel method for thinning copper foil to approximately 4μm using a browning solution with a specific formulation. This method effectively replaces the 18+3μm thick carrier copper foil manufactured using traditional techniques for use in the semi-additive MSAP process. Furthermore, it eliminates the need for an 18μm thick carrier copper layer, thereby reducing the price of conventional copper foil and consequently lowering the cost of SLP-type substrates. This improvement not only enhances processing efficiency but also reduces processing costs, thus solving the problems of thick and expensive carrier copper foil in existing technologies. Attached Figure Description

[0032] Figure 1 This is a diagram illustrating the steps of the method of the present invention. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Please see Figure 1 A substrate-like MSAP fabrication process includes the following steps:

[0035] Step 1: Material preparation: Select copper foil as the starting material. Copper foil is easy to process into the required shape and thickness, which facilitates subsequent processing.

[0036] Step 2, Surface Treatment: Clean and activate the surface of the copper foil to ensure good adhesion;

[0037] Step 3, Browning treatment: Immerse the copper foil in a special browning solution, control the reaction time and temperature, and make the copper foil uniformly thin to 4μm. By controlling the reaction time and temperature, the copper foil can be uniformly thinned to 4μm. Thinner copper foil helps to improve circuit performance, such as reducing signal delay and improving frequency response.

[0038] 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 and prevent it from affecting the effect of subsequent processes. The drying process can prevent the copper foil surface from oxidizing and maintain its good conductivity.

[0039] Step 5, Photoresist Coating: A layer of photoresist is uniformly coated on the thinned copper foil. The photoresist can act as a protective layer to protect the unexposed areas from the etchant. Furthermore, through photolithography, the circuit pattern on the photomask can be precisely transferred onto the photoresist.

[0040] Step 6, Exposure and Development: The photoresist is exposed using a specific photomask and then developed to form the required circuit pattern. The exposure and development process can form high-precision circuit patterns to meet the needs of fine circuits.

[0041] Step 7, Electroplating: Electroplating is performed on the areas not protected by photoresist to form conductive paths. The electroplated layer can enhance conductivity and improve circuit performance.

[0042] Step 8: Remove photoresist: Remove the remaining photoresist using a laser. Laser removal of photoresist allows for precise control of the removal area, avoiding damage to the circuit pattern.

[0043] 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.

[0044] Step 10, Cleaning and Inspection: After etching is completed, the obtained PCB is thoroughly cleaned and quality inspected. Thorough cleaning can remove the residue generated during the etching process and ensure the cleanliness of the PCB.

[0045] Step two, the activation treatment of the copper foil surface, is as follows: The copper foil is placed in a colloidal palladium activation solution and reacted at 20-30℃ for 8-15 minutes. The chemical reaction equation is:

[0046] Pd 2+ +2SnCl2+4HCl→Pd+2SnCl4+2H2+Sn;

[0047] In the reaction formula, Pd 2+ The symbol 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), while stannous chloride is oxidized to stannous tetrachloride (SnCl4). At the same time, some stannous chloride reacts with hydrochloric acid to produce hydrogen chloride (HCl) and hydrogen gas (H2), as well as metallic tin (Sn).

[0048] The composition and proportions of the browning solution are as follows: 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%; mercaptoacetic acid 4.26%–4.66%; 2-mercaptobenzothiazole 0.66%–0.80%; methyltriazole 0.91%–1.02%; anhydrous copper sulfate 5.44%–5.72%; hydrochloric acid 4.07%–4.52%.

[0049] The preparation process of the browning solution is as follows: Prepare standard reagents with the specified component ratios, and mix them thoroughly using a glass stirring rod at a temperature of 5-10℃. Mixing at a low temperature of 5-10℃ helps control the reaction rate, ensures uniform mixing of all components, and avoids uneven composition caused by localized overheating or undercooling. Using a glass stirring rod prevents the introduction of impurities and maintains the purity of the solution.

[0050] Application of browning agent: Dilute the browning agent with pure water at a ratio of 1:5 by weight to ensure that the copper foil is thinned evenly without damaging the substrate. By diluting with pure water at a ratio of 1:5, the concentration of the agent can be reduced, thereby reducing the risk of corrosion to the copper foil substrate, while ensuring that the copper foil can be thinned evenly. This specific dilution method is both economical and environmentally friendly.

[0051] Step 5: Selection of photoresist: Select positive photoresist and deep ultraviolet photoresist. Apply positive photoresist to the surface with a thickness of 0.4-0.8 mm. After drying, apply deep ultraviolet photoresist to the surface with a thickness of 0.2-0.5 mm. This increases the resolution, adhesion, and chemical resistance, improving the accuracy of pattern transfer and reducing light sensitivity. The combined use of positive and deep ultraviolet photoresist forms a thicker protective layer on the surface, improving resolution and adhesion. Deep ultraviolet photoresist has better chemical resistance, reducing light sensitivity and improving the accuracy of pattern transfer.

[0052] The specific photomask exposure process: Using a deep ultraviolet (DUV) photomask under a high-intensity ultraviolet light source, the photoresist is exposed for 5-10 seconds. Using a deep ultraviolet (DUV) photomask under a high-intensity ultraviolet light source can shorten the exposure time and improve production efficiency. The 5-10 second exposure time can ensure that the photoresist is fully cured and forms a clear circuit pattern.

[0053] The electroplating conditions in step seven are set as follows: current density of 1-5 A / dm², temperature of 45-60℃, and duration of 0.5-1 h. These conditions ensure the uniformity and conductivity of the circuit. Appropriate current density and temperature can also improve electroplating efficiency and shorten the processing cycle.

[0054] In step eight, the photoresist is removed by irradiating and evaporating it with a 60-watt laser. This method can quickly and efficiently remove the remaining photoresist without damaging the substrate, thus improving processing efficiency and reducing costs.

[0055] The etching process in step nine is as follows: Ammonium sulfate with a concentration of 20%–30% is selected as the etchant; the reaction temperature is controlled at 45–50℃; and the reaction time is controlled at 3–5 minutes. The chemical equation for the reaction is:

[0056] Cu+(NH4)2SO4→CuSO4+2NH3+H2O;

[0057] In the reaction formula, copper reacts with ammonium sulfate solution to produce copper sulfate, ammonia and water. Etching under these conditions can avoid circuit breakage due to over-etching or short circuits due to under-etching.

[0058] Example 1

[0059] The composition and proportions of the browning solution are as follows: silane coupling agent 1.12%; benzotriazole 2.16%; hydrogen peroxide 5.55%; glycolic acid 3.24%; zinc nitrate 1.10%; mercaptoacetic acid 4.36%; 2-mercaptobenzothiazole 0.68%; methylbenztriazole 0.98%; anhydrous copper sulfate 5.50%; hydrochloric acid 4.47%.

[0060] Example 2

[0061] The composition and proportions of the browning solution are as follows: silane coupling agent 1.51%; benzotriazole 2.22%; hydrogen peroxide 6.00%; glycolic acid 3.34%; zinc nitrate 1.20%; mercaptoacetic acid 4.66%; 2-mercaptobenzothiazole 0.80%; methylbenztriazole 1.02%; anhydrous copper sulfate 5.72%; hydrochloric acid 4.52%.

[0062] Example 3

[0063] The composition and proportions of the browning solution are as follows: silane coupling agent 1.19%; benzotriazole 2.19%; hydrogen peroxide 5.40%; glycolic acid 3.14%; zinc nitrate 1.10%; mercaptoacetic acid 4.46%; 2-mercaptobenzothiazole 0.70%; methylbenztriazole 1.00%; anhydrous copper sulfate 5.62%; hydrochloric acid 4.42%.

[0064] Comparative Example 1

[0065] The composition and proportions of the browning solution are as follows: silane coupling agent 0.98%; benzotriazole 2.01%; hydrogen peroxide 4.55%; glycolic acid 2.44%; zinc nitrate 0.81%; mercaptoacetic acid 3.56%; 2-mercaptobenzothiazole 0.48%; methylbenztriazole 0.88%; anhydrous copper sulfate 5.00%; hydrochloric acid 4.37%.

[0066] Comparative Example 2

[0067] The composition and proportions of the browning solution are as follows: silane coupling agent 1.71%; benzotriazole 3.22%; hydrogen peroxide 7.00%; glycolic acid 4.34%; zinc nitrate 2.20%; mercaptoacetic acid 5.06%; 2-mercaptobenzothiazole 1.80%; methylbenztriazole 1.42%; anhydrous copper sulfate 5.92%; hydrochloric acid 5.52%.

[0068] Comparative Example 3

[0069] The composition and proportions of the browning solution are as follows: silane coupling agent 0.12%; benzotriazole 3.19%; hydrogen peroxide 5.40%; glycolic acid 1.14%; zinc nitrate 1.10%; mercaptoacetic acid 5.46%; 2-mercaptobenzothiazole 0.70%; methylbenztriazole 1.00%; anhydrous copper sulfate 5.62%; hydrochloric acid 5.42%.

[0070] Ingredient Comparison Table 1

[0071] 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 Methyltriazole (%) 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

[0072] The chemical solutions prepared in Examples 1 and 3, and Comparative Examples 1 and 3, were used in the method steps of the present invention, and the thickness (μm), peel strength (N / mm), thermal shock resistance (pass / fail), and micro-etching amount (μm) of the substrates processed with the corresponding chemical solutions were tested. The data are shown in Table 2 below:

[0073] Table 2 Comparison of Performance Indicators of Browning Chemical Solution Formulation

[0074] Case / Test Project Thickness (μm) Peel strength (N / mm) Thermal shock resistance Micro-etching amount (μm) Cost of browning chemicals (compared to traditional processes) Example 1 3.99 1.2 pass 0.5 Decrease of 0.95% Example 2 4.00 1.1 pass 0.4 Decrease of 0.5% Example 3 4.01 0.9 pass 0.3 Down 1.5% Example 1 13 0.9 fail 0.3 Decrease of 0.8% Example 2 13 0.9 fail 0.3 Decrease of 1.15% Example 3 9 0.6 fail 0.2 Decrease of 0.1%

[0075] Note: 3.95μm ≤ standard thickness (μm) ≤ 4.05μm;

[0076] Information obtained from Tables 1 and 2:

[0077] The browning agent formulations of Examples 1, 2, and 3 all exhibited good performance in terms of thickness, peel strength, thermal shock resistance, and micro-etching amount. Furthermore, the thickness of the carrier-like plates in these examples was approximately 4 μm, the peel strength was between 0.9 and 1.2 N / mm, the thermal shock resistance test was passed, and the micro-etching amount was 0.3 to 0.5 μm. In comparison, the carrier-like plates of Comparative Examples 1 and 3 performed poorly in terms of thickness (μm), peel strength (N / mm), thermal shock resistance (pass / fail), and micro-etching amount (μm), especially failing the thermal shock resistance test. Their thicknesses were between 9 and 13 μm, failing to meet the standard thickness specifications. This indicates that the composition and proportions of the comparative examples exceeded the specific gravity range of the formulation of this invention, leading to the aforementioned performance degradation. Additionally, the cost of the browning agent in the examples and comparative examples was reduced compared to the traditional process, with a reduction ranging from 0.1% to 1.5%.

[0078] The above results demonstrate that the novel method of using the browning solution in the formulation of this invention to thin copper foil to approximately 4 μm can effectively replace the 18+3 μm thick carrier copper foil manufactured by traditional technology for use in the semi-additive MSAP process. Furthermore, it eliminates the need for an 18 μm thick carrier copper layer, thereby reducing the price of conventional copper foil and consequently lowering the cost of SLP-type substrates. This improvement not only enhances processing efficiency but also reduces processing costs, thus solving the problem of thick and expensive carrier copper foil in existing technologies.

[0079] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A MSAP processing methodology of a board-like object, characterized by, It comprises the following steps: Step one, material preparation: select copper foil as the starting material; Step two, surface treatment: clean and activate the surface of the copper foil; Step three, brown liquor treatment: immerse the copper foil in a specially prepared brown liquor, control the reaction time and temperature, and uniformly thin the copper foil to 4 microns; Step four, cleaning and drying: take out the copper foil from the brown liquor, clean it, and then dry it in an oven; Step five, photoresist coating: evenly coat a layer of photoresist on the thinned copper foil; Step six, exposure and development: expose the photoresist using a specific photomask, then develop it to form the desired circuit pattern; Step seven, electroplating: electroplate in the areas not protected by the photoresist to form conductive paths; Step eight, remove the photoresist: remove the remaining photoresist by laser; Step nine, etching: use etchant to remove excess copper foil, leaving the circuit pattern; Step ten, cleaning and inspection: after etching, clean the obtained PCB and conduct quality inspection; The composition and ratio of the brown liquor are as follows: 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%, mercaptoacetic acid 4.26%-4.66%, 2-mercaptobenzothiazole 0.66%-0.80%, methylbenzotriazole 0.91%-1.02%, anhydrous copper sulfate 5.44%-5.72%, and hydrochloric acid 4.07%-4.52%; The exposure process of the specific photomask: use a deep ultraviolet photomask under a high-intensity ultraviolet light source to expose the photoresist for 5-10 seconds.

2. A MSAP processing method of a kind of carrier plate according to claim 1, characterized in that: The activation process of the copper foil surface in step two is as follows: place the copper foil in a colloidal palladium activation solution and react for 8-15 minutes at a temperature of 20-30°C. The chemical reaction equation is as follows: Pd 2+ + 2 SnCl2 + 4 HC1 → Pd + 2 SnCl4 + 2 H2 + Sn; In the reaction formula, Pd 2+ represents the palladium ion in palladium chloride, SnCl2represents stannous chloride, and HCl represents hydrochloric acid. During the reaction, the palladium ion is reduced to metallic palladium, and stannous chloride is oxidized to stannic chloride. At the same time, part of the stannous chloride reacts with the hydrochloric acid to produce hydrogen chloride and hydrogen gas, and metallic tin.

3. A MSAP processing method of a kind of carrier plate according to claim 1, characterized in that: The preparation process of the brown liquor is as follows: prepare the standard reagents according to the ratio, mix them uniformly at a temperature of 5-10°C using a glass stirring rod, and the brown liquor is prepared.

4. A MSAP processing method of claim 3, wherein: The use of the brown liquor: dilute the brown liquor with pure water at a ratio of 1:5 by weight.

5. A MSAP processing method of claim 1, wherein: The selection of photoresist in step five: select positive photoresist and deep ultraviolet photoresist, apply the positive photoresist to the surface with a thickness of 0.4-0.8 mm, and after drying, apply the deep ultraviolet photoresist to the surface with a thickness of 0.2-0.5 mm.

6. A MSAP processing methodology of claim 1, wherein: The setting of electroplating conditions in step seven: current density is 1-5 A / dm², temperature is 45-60°C, and time is 0.5-1 hour.

7. A MSAP processing method of claim 1, wherein: The removal of photoresist in step eight: use a 60-watt laser to irradiate and evaporate the photoresist to remove the remaining photoresist.

8. A MSAP processing method of claim 1, wherein: The etching process in step nine is as follows: select 20%-30% 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 as follows: Cu+(NH4)2SO4→CuSO4+2NH3+H2O; In the reaction, copper reacts with ammonium sulfate solution to produce copper sulfate, ammonia gas, and water.

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