Electroplating liquid leveling agent for advanced packaging copper cylinder and electroplating liquid
By using vinyl nitrogen heterocyclic polymers or copolymers as levelers in the copper pillar electroplating solution, the problem of plating defects in the micromorphology adjustment of the copper pillar top is solved, and the controllability of the copper pillar morphology and the improvement of packaging yield are achieved.
Patent Information
- Application Number
- CN202510778329.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-11
- Publication Date
- 2025-09-23
AI Technical Summary
In the prior art, there is a risk of residual additives in the copper pillar electroplating solution when adjusting the micromorphology of the copper pillar top, which can easily cause plating defects and affect the chip packaging yield.
A copper pillar electroplating solution for advanced semiconductor packaging is formed by using vinyl nitrogen heterocyclic polymers or copolymers as levelers, in combination with brighteners and inhibitors. The controllable micromorphology of the copper pillar top is achieved by controlling the dosage of the leveler.
The top surface of the copper pillar is bright and delicate, the plating layer is defect-free, the copper pillar morphology is controllable, and the yield rate of chip packaging is improved.
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Figure CN120683572A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a copper column electroplating solution leveler, in particular to a semiconductor advanced packaging copper column electroplating solution leveler, and especially to an electroplating solution leveler with controllable micromorphology of copper column top bumps. Background Art
[0002] In recent years, with the rapid development of the global semiconductor industry and the continuous advancement of thinner, higher-performance, and more multifunctional devices, the demand for electronic chemicals used in semiconductor packaging has continued to increase to meet the growing needs of the chip industry. Electronic chemicals, to a certain extent, determine the development and progress of downstream and end-user industries. Flip-chip technology is commonly used for packaging below the 45nm node. This effectively addresses the challenges of small chip size and high integration. To meet the needs of chip miniaturization and the increase in the number of multifunctional I / Os, bumping is a key process technology for flip-chip implementation. Copper pillar bonding replaces traditional wire bonding to achieve electrical interconnection between the chip and the substrate. Copper pillar bumping is a key process in the Under Bump Metallization (UBM) process, enabling the integration of various chip functions in system-in-package (SiP).
[0003] Copper electroplating solution is a core material in the advanced packaging manufacturing process. As chip technology miniaturizes, bump size is shrinking, increasing the demand and technical requirements for copper pillars. To improve copper pillar purity, minimize the impact of impurities (particles) on electrical signals, and reduce thermal losses, electroplating additives must be confined and precise. These additives must not only be highly functional, but also maintain strict control over both the overall uniformity of the bumps and the micromorphology of individual copper pillars. Conventional commercial additives typically combine two or more to achieve precise micromorphology at the copper pillar tip. This not only carries the risk of additive residue in the plating layer, but can also lead to microscopic defects in the copper pillar plating structure, such as Kirkendall voids. These defects can hinder subsequent bonding processes, hinder higher-density electrical connections, and ultimately impact the overall yield of chip packaging. Summary of the Invention
[0004] To address the shortcomings of the prior art, the present invention aims to provide a leveler for copper pillar electroplating solutions for advanced semiconductor packaging. The leveler comprises an aqueous solution of a vinyl nitrogen heterocyclic polymer or copolymer. This leveler, combined with a brightener, suppressor, and base solution, not only produces a bright and fine copper coating with a defect-free cross-section, but also enables controllable micromorphology of the copper pillar bumps.
[0005] The solution adopted by the present invention to solve the above technical problems is: A leveler for semiconductor advanced packaging copper pillar electroplating solution, with the general structural formula: , where m=0~40, n=10~50.
[0006] Preferably, the leveling agent R1 is (dihydropyridine), (pyrrole), Any compound of (pyrrolidone).
[0007] Preferably, the leveling agent R2 is (imidazole), (pyrazole), (N-tetrahydropyridine), (dihydropyrimidine), (dihydroquinoline), Any compound of the purine group.
[0008] A copper pillar electroplating solution for advanced packaging comprises the above-mentioned leveling agent.
[0009] Preferably, the copper column electroplating solution further includes a base solution, a brightener, and an inhibitor.
[0010] Preferably, the amount of the leveling agent added is 0.05mg / L~50mg / L. Preferably, when the amount of the leveling agent added is 0.05mg / L~5mg / L (including 0.05mg / L and 5mg / L), the surface morphology of the top of the copper column is slightly convex (such as Figure 1 As shown); preferably, when the leveling agent is added in an amount of 5 mg / L to 10 mg / L, the surface morphology of the top of the copper column is flat (as shown Figure 2 As shown); preferably, when the leveling agent is added in an amount of 10 mg / L to 50 mg / L (including 10 mg / L and 50 mg / L), the surface morphology of the top of the copper column is slightly concave (as shown Figure 3 shown).
[0011] Preferably, the base liquid is copper sulfate pentahydrate, sulfuric acid and a small amount of hydrochloric acid, and the addition amounts of the base liquid are: copper sulfate pentahydrate 100-250 g / L, sulfuric acid 50-150 g / L, and hydrochloric acid 50-100 ppm.
[0012] Preferably, the brightener is sodium polydisulfide bis(propylene sulfonate) (SPS), and the addition amount of the brightener is 5 mg / L to 50 mg / L.
[0013] Preferably, the inhibitor is polyethylene glycol with a molecular weight of 1000-8000, and the added amount of the inhibitor is 100-500 mg / L.
[0014] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: The leveler in this invention, combined with a base solution, brightener, and inhibitor, effectively leveled the copper pillar in the electroplating solution, preventing defects such as microscopic voids in the coating. Furthermore, the leveler, while requiring minimal dosage, effectively modulates the microscopic morphology of the plated copper pillar tips, achieving a transition from slightly convex to slightly concave topography without affecting the coating structure or plating rate.
[0015] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following is a detailed description in conjunction with the preferred embodiments. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments are briefly introduced below.
[0017] Figure 1 It is a schematic diagram of the structure of slight convexity, flattening and slight concaveness.
[0018] Figure 2 The 3D profilometer test results of Example 1 of the present invention are shown. Figure (a) shows that the top of a single Cu pillar presents a slightly convex morphology. Figure (b) shows the cross-sectional linear morphology of the copper pillar.
[0019] Figure 3 The 3D profilometer test results of Example 2 of the present invention are shown. Figure (c) shows that the top of a single Cu pillar has a flat morphology. Figure (d) shows the cross-sectional linear morphology of the copper pillar.
[0020] Figure 4 The 3D profilometer test results of Example 3 of the present invention are shown. Figure (e) shows that the top of a single Cu pillar presents a slightly concave morphology. Figure (f) shows the cross-sectional linear morphology of the copper pillar. DETAILED DESCRIPTION
[0021] The embodiment was subjected to electroplating application test, and the specific method is as follows: An 8-inch bump structure wafer was placed in an 8-inch, 10L simple electroplating apparatus connected to a rectifier for electroplating experiments. The same current density and plating time were used: 3 ASD 800s, 6 ASD 300s, and 9 ASD 800s. After electroplating, the photoresist was stripped, and the plated hole filling and surface morphology were observed using a 50x interference lens on a 3D profilometer.
[0022] The specific embodiments of the present invention are described in detail below.
[0023] Example 1
[0024] Among them, the structural formula of leveler 1 (polyvinyl purine-10) is as follows: In leveling agent 1, m=0, n=10. (This structure and the leveling agents in Examples 2 to 8 below are all custom-made samples.) Preparation method of copper pillar electroplating solution for advanced packaging (taking the preparation of 10L electroplating solution as an example): First, use pure water to calibrate the exact position of the 10L liquid level inside and outside the 20L preparation barrel, make scale marks, empty the preparation barrel, and dry it with nitrogen. Then, add a certain amount of deionized water to the preparation barrel, slowly add sulfuric acid, stir evenly, add the pre-weighed copper sulfate pentahydrate, and stir thoroughly to dissolve. Next, use a 1-10mL pipette to pipette and add a certain amount of accelerator, inhibitor, and leveler that have been pre-prepared into a 5% aqueous solution. After cooling, use a filter equipped with a 0.5μm filter element to circulate and filter the above mixed solution for 1-2 hours. Finally, add deionized water to the preparation barrel to the pre-calibrated position to obtain the copper pillar electroplating solution for advanced packaging.
[0025] Figure 2 Figure 3 shows the 3D profilometer test results of Example 1 of the present invention. With a certain amount of leveling agent, Figure (a) shows that the tip of a single Cu pillar exhibits a slightly convex morphology. Figure (b) shows the linear cross-sectional morphology of the copper pillar, with a slightly convex tip and a flat, defect-free surface, verifying the good morphology of Figure (a).
[0026] Example 2
[0027] The structural formula of leveling agent 2 (polyvinyl dihydropyridine-10 and polyvinyl imidazole-20 copolymer) is as follows: , in leveler 2, m=10, n=20.
[0028] The preparation method of the copper pillar electroplating solution for advanced packaging is the same as that in Example 1.
[0029] Figure 3 Figure 2 shows the 3D profilometer test results of Example 2 of the present invention. With a certain amount of leveling agent, Figure (c) shows that the top of a single Cu pillar exhibits a flat morphology. Figure (d) shows the linear morphology of the cross-section of the copper pillar, with a flat top and a smooth, defect-free surface, confirming the good morphology of Figure (c).
[0030] Example 3
[0031] The structural formula of leveler 3 (polyvinylpyrrole-40 and polyvinylpyrazole-10 copolymer) is as follows: , in leveler 3, m=40, n=10.
[0032] The preparation method of the copper pillar electroplating solution for advanced packaging is the same as that in Example 1.
[0033] Figure 4 Figure 3 shows the 3D profilometer test results of Example 3 of the present invention. With a certain amount of leveling agent, Figure (e) shows a slightly concave top surface at the tip of a single Cu pillar. Figure (f) shows the linear cross-sectional morphology of the copper pillar, with a slightly concave top surface and a flat, defect-free surface, confirming the good morphology of Figure (e).
[0034] Example 4
[0035] Among them, the structural formula of leveling agent 4 (polyvinyldihydroquinoline-50) is as follows: , in leveler 4, m=0, n=50.
[0036] The preparation method of the copper pillar electroplating solution for advanced packaging is the same as that in Example 1.
[0037] Example 5
[0038] The structural formula of leveling agent 5 (polyvinyl pyrrolidone-40 and polyvinyl dihydropyrimidine-50 copolymer) is as follows: , in leveling agent 5, m=40, n=50.
[0039] The preparation method of the copper pillar electroplating solution for advanced packaging is the same as that in Example 1.
[0040] Example 6
[0041] The structural formula of leveler 6 (polyvinyl dihydropyridine-15 and polyvinyl N-tetrahydropyridine-50 copolymer) is as follows: , in leveling agent 6, m=15, n=50.
[0042] The preparation method of the copper pillar plating solution for advanced packaging is the same as that in Example 1.
[0043] Example 7
[0044] The structural formula of leveling agent 7 (polyvinylpyrrole-25 and polyvinylimidazole-10 copolymer) is as follows: , in leveler 7, m=25, n=10.
[0045] The preparation method of the copper pillar electroplating solution for advanced packaging is the same as that in Example 1.
[0046] Example 8
[0047] The structural formula of leveling agent 8 (polyvinyl pyrrolidone-20 and polyvinyl pyrazole-40 copolymer) is as follows: , in leveling agent 8, m=20, n=40.
[0048] The preparation method of the copper pillar electroplating solution for advanced packaging is the same as that in Example 1.
[0049] In the above examples, the leveler, along with other additives, maintains the stability of the copper electroplating solution and is a key factor in controlling the plating rate, surface, and internal morphology of the copper coating. However, the leveler in this invention is the only additive capable of achieving controllable micromorphology at the copper pillar tips. The additives used in the above examples are all within the optimal range.
[0050] like Figure 1 As shown, the microscopic morphology of a single copper column is expressed by TIR, TIR=(H Center -H Edge ) / H maxThe industry's standard TIR value is -10% to 10% (inclusive of ±10%). TIR values within this range are considered acceptable, while values outside this range are considered unacceptable. The TIR value varies depending on the leveling agent dosage, revealing different micromorphological features of the copper pillar tips. When the leveling agent addition amount is 0.05mg / L~5mg / L (including 0.05mg / L and 5mg / L), the TIR qualified range is 2%~10% (including 10%), and the surface morphology of the top of the copper pillar is slightly convex (as shown in schematic diagram (1)); when the leveling agent addition amount is 5mg / L~10mg / L, the TIR qualified range is -2%~2% (including ±2%), and the surface morphology of the top of the copper pillar is flat (as shown in schematic diagram (2)); when the leveling agent addition amount is 10mg / L~50mg / L (including 10mg / L and 50mg / L), the TIR qualified range is -10%~-2% (including -10%), and the surface morphology of the top of the copper pillar is slightly concave (as shown in schematic diagram (3)). According to the distribution of 8-inch wafer die, 128 sample points are evenly selected to test the TIR value of each copper pillar, and the average value is recorded as the TIR value of the wafer.
[0051] The electroplating effects and evaluations of the copper column electroplating solutions of Examples 1 to 8 are shown in the following table:
[0052] Figure 2 、 Figure 3 and Figure 4 The surface morphology of the copper pillar is complete, the plating layer is dense, and there are no defects such as defects and holes. This shows that the leveling agent plays a good leveling role on the copper plating layer in the copper pillar electroplating solution formula. At the same time, the top morphology can be directional adjusted by adjusting the amount of additive.
[0053] All the raw materials listed in the present invention, as well as the upper and lower limits and interval values of the raw materials in the present invention can realize the present invention, and the embodiments are not listed one by one here.
[0054] The above description is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and changes can be made without departing from the principles of the present invention. These improvements and changes are also considered to be within the scope of protection of the present invention.
Claims
1. A leveler for advanced packaging copper pillar electroplating solution, characterized in that: The general structural formula of the electroplating solution leveler is: , where m=0~40, n=10~50.
2. The copper pillar electroplating solution leveler for advanced packaging according to claim 1, characterized in that: The leveling agent R1 is (dihydropyridine), (pyrrole), (pyrrolidone) any one.
3. The copper pillar electroplating solution leveler for advanced packaging according to claim 1, characterized in that: The leveling agent R2 is (imidazole), (pyrazole), (N-tetrahydropyridine), (dihydropyrimidine), (dihydroquinoline), Any of the purines.
4. A copper pillar electroplating solution for advanced packaging, characterized in that: The copper column electroplating solution comprises any one of the levelers described in claim 1, 2, or 3.
5. The copper pillar electroplating solution for advanced packaging according to claim 4, characterized in that The copper column electroplating solution also includes a base solution, a brightener, and an inhibitor.
6. The copper pillar electroplating solution for advanced packaging according to claim 4, characterized in that The added amount of the leveling agent is 0.05 mg / L to 50 mg / L.
7. The copper pillar electroplating solution for advanced packaging according to claim 6, characterized in that When the leveling agent is added in an amount of 0.05 mg / L to 5 mg / L, the surface morphology of the top of the copper column is slightly convex; When the leveling agent is added in an amount of 5 mg / L to 10 mg / L, the surface morphology of the top of the copper column is flat; When the leveling agent is added in an amount of 10 mg / L to 50 mg / L, the surface morphology of the top of the copper column is slightly concave.
8. The copper pillar electroplating solution for advanced packaging according to claim 5, characterized in that The base liquid is copper sulfate pentahydrate, sulfuric acid and hydrochloric acid, and the addition amounts of the base liquid are: copper sulfate pentahydrate 100-250g / L, sulfuric acid 50-150g / L, and hydrochloric acid 50-100ppm.
9. The copper pillar electroplating solution for advanced packaging according to claim 5, characterized in that The brightener is sodium polydisulfide dipropane sulfonate SPS, and the addition amount of the brightener is 5 mg / L to 50 mg / L.
10. The copper pillar electroplating solution for advanced packaging according to claim 5, characterized in that The inhibitor is polyethylene glycol with a molecular weight of 1000-8000, and the added amount of the inhibitor is 100-500 mg / L.