Acid bank protection agent and application thereof

Abstract

The invention discloses an acidic bank protection agent, and belongs to the field of semiconductor manufacturing. The main components of the cleaning agent are lauryl sodium sulfate (C12H25SO4Na) and ammonium salt. And in the process of time, the dodecyl sulfate radicals are combined with cuprous to generate cuprous dodecyl sulfate which is deposited on the surface of copper. According to the invention, the technical effects of rapidly reducing burrs and improving etching factors in the etching link of the semiconductor class production process are realized.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing, in particular to a shore protection agent, especially an acidic shore protection agent and application thereof. Background Art

[0002] First, with the continuous upgrading of electronic products, PCB circuit board production faces increasingly fine and dense circuits. To address this, etching equipment has added vacuum etching and two-fluid etching, greatly improving etching capabilities. However, when faced with the production of thick copper, high-density fine circuits, there are still many difficulties, and etching quality needs to be improved.

[0003] However, in existing technologies, acidic etching solutions are difficult to remove due to residual grease and oil residues left after the previous development process, as well as sweat (containing organic matter such as urea) and grease left behind by careless handling. This can lead to localized copper residue after etching. Furthermore, there are also problems such as excessive burrs and undercuts during etching, as well as insufficient etching factors. Summary of the Invention

[0004] On the one hand, the technical problem to be solved by the present invention is to provide an acidic bank protection agent, which solves the technical problems of insufficient residual grease removal effect, excessive product burrs and excessive etching side etching, and insufficient etching factor in the prior art, and at least achieves one of the technical effects of effectively removing residual grease, quickly reducing burrs, properly etching, and improving the etching factor.

[0005] In order to solve the above technical problems, the technical solution of the present invention is:

[0006] An acidic bank protection agent, the main component of which is sodium lauryl sulfate (C 12 H 25 SO4Na) and ammonium salt; during the reaction, dodecyl sulfate combines with cuprous sulfate to form dodecyl cuprous sulfate which is deposited on the copper surface.

[0007] Preferably, the etching factor of the acidic revetment agent follows the following formula:

[0008] EF=2h / (ba), where a is the width of the gap reserved in the corrosion-resistant layer; b is the width of the etched copper layer; and h is the depth of the etched copper layer.

[0009] Preferably, the acidic bank protection agent is a weakly acidic surfactant.

[0010] Preferably, the acidic bank protection agent is a transparent liquid.

[0011] Preferably, the acidic bank protection agent has no solid components.

[0012] Preferably, the acidic bank protection agent generates bubbles under violent movement.

[0013] More preferably, the acidic bank protection agent can remove organic matter and grease containing urea.

[0014] Particularly preferably, the reaction process of cupric chloride-based acid etching includes the following reactions:

[0015] The divalent copper ions (Cu2+) in the solution react with metallic copper according to the following reaction formula:

[0016] Cu 2+ +Cu→2Cu + ;

[0017] Then Cu + Combined with chloride ions (Cl) in the solution to form insoluble CuCl, the reaction proceeds according to the following reaction formula:

[0018] Cu + +Cl - →CuCl↓,

[0019] The precipitation of cuprous chloride will hinder the etching reaction;

[0020] in,

[0021] Cu+ or CuCl is oxidized to Cu in an environment with strong oxidizing power. 2+ :

[0022] 4Cu + +O2+4H + →4Cu + +2H2O or

[0023] 4CuCl+O2+4H + →4Cu + +4Cl - +2H2O;

[0024] The above reaction is the regeneration of the acid etching solution.

[0025] Another problem to be solved by the present invention is to provide an application of an acidic revetment agent, wherein the application scenarios include acid etching of IC substrates, HDI boards, FPBC boards or PCB boards.

[0026] One or more technical solutions provided in this application have at least the following technical effects or advantages:

[0027] The above technical solution adopts sodium lauryl sulfate (C 12 H 25SO4Na) and ammonium salts and a series of technical means make it possible that during the etching process, dodecyl sulfate combines with cuprous sulfate to generate dodecyl cuprous sulfate which is deposited on the copper surface, effectively solving the technical problems of insufficient residual grease removal effect, excessive product burrs, excessive etching side etching and insufficient etching factor in the prior art, thereby achieving the technical effects of effectively removing residual grease, quickly reducing burrs, properly etching and improving etching factor. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the revetment principle of the acid etching solution itself;

[0029] Figure 2 Schematic diagram of the revetment mechanism of the etching process in the early stage of etching;

[0030] Figure 3 Schematic diagram of the revetment mechanism of the etching process in the middle stage of etching;

[0031] Figure 4 Schematic diagram of the revetment mechanism of the etching process at the end of etching;

[0032] Figure 5 Schematic diagram of the mechanism for removing oil stains. Figure 6 Schematic diagram of the etching factor calculation formula. DETAILED DESCRIPTION

[0033] The following is a further description of specific embodiments of the present invention in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is intended to facilitate understanding of the present invention and does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0034] The revetment agent mainly solves the problems of excessive burrs and excessive side etching during etching. During the production process (under the same conditions), the addition of the acidic revetment agent (model XO-290) according to the embodiment of the present invention can quickly reduce the burrs by 50-80%, and the etching factor can be increased by at least 50% and at most 150% or even higher.

[0035] The technical solution of the embodiment of the present application solves the problems of excessive side etching, excessive burrs and low etching factor in the prior art by providing an acidic revetment agent. The addition of the acidic revetment agent of the embodiment of the present invention achieves the beneficial effects of significantly reducing burrs and improving the etching factor.

[0036] The overall idea of ​​the implementation scheme of the present invention to solve the above technical problems is as follows:

[0037] An acidic bank protection agent, the main component of which is sodium lauryl sulfate (C12 H 25 SO4Na) and ammonium salts; during the etching process, dodecyl sulfate combines with cuprous sulfate to form cuprous dodecyl sulfate, which is deposited on the copper surface. The shore protection agent contains surfactants that help remove these greases and effectively reduce residual copper. At the end of the etching process, the exposed copper layer is less likely to be precipitated by cuprous chloride or activator-cuprous compounds due to the spraying effect, allowing it to be etched cleanly. The thick protective layer beneath the "eaves" of the etch-stop layer protects the sidewalls from further etching, making them nearly vertical, resulting in minimal side erosion and a high etching factor.

[0038] The application scenarios of the embodiments of the present application include acid etching of IC substrates, HDI boards, FPBC boards or PCB boards. The basic principle of the bank protection agent is shown in the figure.

[0039] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0040] An acidic bank protection agent, the main component of which is sodium lauryl sulfate (C 12 H 25 SO4Na) and ammonium salt; during the reaction, dodecyl sulfate combines with cuprous sulfate to form dodecyl cuprous sulfate which is deposited on the copper surface.

[0041] Preferably, the etching factor of the acidic revetment agent follows the following formula:

[0042] EF=2h / (ba), where a is the width of the gap reserved in the corrosion-resistant layer; b is the width of the etched copper layer; and h is the depth of the etched copper layer.

[0043] Among them, the acidic bank protection agent is a weakly acidic surfactant.

[0044] Specifically, the acidic bank protection agent is a transparent liquid.

[0045] More specifically, the acidic revetment agent has no solid components.

[0046] Specifically, acidic bank protection agents produce bubbles under violent movement.

[0047] Acidic revetment agents can remove organic matter and grease containing urea.

[0048] When the acidic revetment agent is used for revetment, the copper ions (Cu2+) in the solution react with the metallic copper according to the following reaction formula:

[0049] Cu 2+ +Cu→2Cu + ;

[0050] Then Cu +Combined with chloride ions (Cl) in the solution to form insoluble CuCl, the reaction proceeds according to the following reaction formula:

[0051] Cu + +Cl - →CuCl↓,

[0052] The precipitation of cuprous chloride will hinder the etching reaction;

[0053] in,

[0054] Cu+ or CuCl is oxidized to Cu in an environment with strong oxidizing power. 2+ :

[0055] 4Cu + +O2+4H + →4Cu + +2H2O or

[0056] 4CuCl+O2+4H + →4Cu + +4Cl - +2H2O;

[0057] The above reaction is the regeneration of the acid etching solution.

[0058] The above embodiment of the acidic shore protection agent X-290 is a weak acid surfactant, the main component of which is dodecane.

[0059] Sodium sulfate (C2H2sSO4Na), ammonium salts, etc. are all substances that are easily soluble in water.

[0060] Acidic bank protection agent X-290 has the appearance of a transparent liquid with no solid components; bubbles will be generated after shaking.

[0061] During the etching process, dodecyl sulfate will combine with cuprous sulfate to form dodecyl cuprous sulfate which is deposited on the copper surface, achieving a revetment effect, thereby improving the etching quality and increasing the etching factor.

[0062] Another problem to be solved by the embodiments of the present invention is to provide an application of an acidic revetment agent, wherein the application scenarios include acid etching of IC substrates, HDI boards, FPBC boards or PCB boards.

[0063] Mechanism of action

[0064] 1. Mechanism of assisting in oil removal

[0065] The metal layer of the PCB to be etched is prone to residual grease after the previous development process, or sweat (containing urea and other organic matter) and grease left by careless manual handling. Generally, acidic etching solutions are not easy to remove, which will lead to local copper residue after etching.

[0066] Our bank protection agent contains surfactants, which can help remove these greases and effectively reduce the residual copper phenomenon.

[0067] Figure 5 This is a schematic diagram of how the lipophilic group (long strip) of a surfactant helps remove oil stains.

[0068] 2. Etching reaction of common etching solution and CuCl revetment mechanism

[0069] 1. The divalent copper ions (Cu2+) in the solution react with metallic copper; Cu 2+ +Cu→2Cu+

[0070] Rough etching layer (such as dry film)

[0071] 2. Cu+ combines with chloride ions (Cl) in the solution to form insoluble CuCl

[0072] Cu + +Cl - →CuCl precipitation will hinder the etching reaction

[0073] 3. Cu+ or CuCl is oxidized to Cu in an environment with strong oxidizing ability. 2+

[0074] 4Cu + +O2+4H + →4Cu + +2H2O or

[0075] 4CuCl+O2+4H + →4Cu + The above reaction of +4Cl+2H2O is the regeneration of acidic etching solution.

[0076] Bank protection mechanism during etching process: initial stage of etching

[0077] In the early stage of etching, Figure 2 As shown, in a chlorine-rich environment, divalent copper and zero-valent copper react to form cuprous chloride or a compound of activator and cuprous chloride, which is quickly washed away by the spray of the liquid.

[0078] Because the side walls are protected by the "eaves" of the erosion-resistant layer, more sediment will be retained, forming a "bank protection" effect.

[0079] Bank protection mechanism during etching process: mid-etching

[0080] Etching mid-term, such as Figure 3 As shown, the reaction continues to generate cuprous chloride or a compound of the activator and cuprous chloride, and the precipitate on the surface of the copper layer can still be quickly washed away under the spraying of the liquid.

[0081] Although the scouring is weak, the cuprous chloride precipitates on the side walls will still be gradually washed away, while the hydrophobic groups of the compound of activator and cuprous chloride are not easily carried away by the liquid, forming a thick protective layer.

[0082] Bank protection mechanism during etching process: late etching stage

[0083] At the end of etching, Figure 4 As shown in the figure, due to the spraying effect, the copper layer exposed to the outside is less precipitated by cuprous chloride or activator and cuprous compound, so it can be etched cleanly;

[0084] The thick protective layer under the "eaves" of the corrosion-resistant layer has been protecting the side wall from being etched further. The side wall is almost a vertical surface, so the side erosion is small and the etching factor is large, forming a good bank protection effect and avoiding insufficient etching and excessive etching.

[0085] The method of using the shore protection agent according to the embodiment of the present invention is as follows:

[0086] 1. Operating conditions:

[0087] parameter XO-290 (acidic shore protection agent) CU(g / L) 120-190 HCl(N) 1.6-2.2 (hydrogen peroxide series below 2.5) proportion 1.275-1.375 temperature 45℃-55℃ Acidic shore protection agent (XO-290) 4% open cylinder

[0088] 1) The same operating conditions as ordinary copper chloride solution;

[0089] 2) Acidic bank protection agent (XO-290) - add 1%-1.5% of hydrochloric acid to the replenishment tank during standard operation;

[0090] 3) The etching rate is about 3% lower than that of ordinary copper chloride solution.

[0091] 2. Matching slot

[0092] Tank volume 1000L standard:

[0093] 1) Add bank protection agent XO-290 into the tank at a rate of 4% of the tank solution and circulate for 10-15 minutes;

[0094] 2) Bank protection agent supplementation method: During the production process, add 1%-1.5% of XO-290 into the hydrochloric acid supplementation tank to fully dissolve it in the hydrochloric acid;

[0095] 3. Etching factor calculation formula:

[0096] Etching factor EF = 2h / (ba)

[0097] 4. Physical properties

[0098] Product Name Acidic bank protection agent XO-290 form liquid Appearance Transparent (bubbles are generated when moving) stability Non-flammable and non-explosive proportion 1.02±0.05

[0099] From the above, it can be seen that adding the acidic revetment agent (model XO-290) according to the embodiment of the present invention during the production process (under the same conditions) can quickly reduce burrs by 50-80%, and the etching factor can be increased by at least 50% and at most 150% or even higher.

[0100] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. It is apparent to those skilled in the art that various changes, modifications, substitutions, and variations to these embodiments may be made without departing from the principles and spirit of the present invention, and these changes and modifications still fall within the scope of protection of the present invention.

Claims

1. An acidic bank protection agent, characterized in that: Its main component is sodium lauryl sulfate (C 12 H 25 SO4Na) and ammonium salt; during the reaction, dodecyl sulfate combines with cuprous sulfate to form dodecyl cuprous sulfate which is deposited on the copper surface.

2. The acidic shore protection agent according to claim 1, characterized in that: The etching factor of the acidic revetment agent follows the following formula: EF=2h / (ba), where a is the width of the gap reserved in the corrosion-resistant layer; b is the width of the etched copper layer; and h is the depth of the etched copper layer.

3. The acidic shore protection agent according to claim 1, characterized in that: The acidic bank protection agent is a weakly acidic surfactant.

4. The acidic shore protection agent according to claim 1, characterized in that: The acidic bank protection agent is a transparent liquid.

5. The acidic shore protection agent according to claim 1, characterized in that: The acidic bank protection agent has no solid components.

6. The acidic shore protection agent according to claim 1, characterized in that: The acidic bank protection agent generates bubbles under violent movement.

7. The acidic shore protection agent according to claim 1, characterized in that: The acidic shore protection agent can remove organic matter and grease containing urea.

8. The acidic shore protection agent according to claim 1, characterized in that: The reaction process of copper chloride acid etching includes the following reactions: The reaction between divalent copper ions (Cu2+) and metallic copper is carried out according to the following reaction formula: With 2+ +Cu→2Cu + ; Then Cu + Combined with chloride ions (Cl) in the solution to form insoluble CuCl, the reaction proceeds according to the following reaction formula: With + +Cl - →CuCl; The precipitation of cuprous chloride will hinder the etching reaction; in, Cu+ or CuCl is oxidized to Cu in an environment with strong oxidizing power. 2+ : 4Cu + +O2+4H + →4Cu + +2H2O or 4CuCl+O2+4H + →4Cu + +4Cl - +2H2O; The above reaction is the regeneration of the acid etching solution.

9. The use of the acidic shore protection agent according to any one of claims 1 to 8, characterized in that: Its application scenarios include acid etching of IC substrates, HDI boards, FPBC boards or PCB boards.

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