CN111778545A - Micropore filling method based on small-size quaternary ammonium salt single additive - Google Patents
Micropore filling method based on small-size quaternary ammonium salt single additive Download PDFInfo
- Publication number
- CN111778545A CN111778545A CN202010760001.1A CN202010760001A CN111778545A CN 111778545 A CN111778545 A CN 111778545A CN 202010760001 A CN202010760001 A CN 202010760001A CN 111778545 A CN111778545 A CN 111778545A
- Authority
- CN
- China
- Prior art keywords
- electroplating
- quaternary ammonium
- ammonium salt
- small
- size
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D21/00—Processes for servicing or operating cells for electrolytic coating
- C25D21/12—Process control or regulation
- C25D21/14—Controlled addition of electrolyte components
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D3/00—Electroplating: Baths therefor
- C25D3/02—Electroplating: Baths therefor from solutions
- C25D3/38—Electroplating: Baths therefor from solutions of copper
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D7/00—Electroplating characterised by the article coated
- C25D7/12—Semiconductors
- C25D7/123—Semiconductors first coated with a seed layer or a conductive layer
Abstract
The invention provides a micropore filling method based on a small-size quaternary ammonium salt single additive. The method adopts small-size quaternary ammonium salt with anode property as an inhibitor for micropore electroplating filling, immerses a pure copper plate into electroplating solution as an anode, immerses a silicon wafer containing micropores into the electroplating solution as a cathode, and electroplates and fills the micropores of the silicon wafer; the invention has better micropore electroplating filling effect, higher efficiency and lower cost.
Description
Technical Field
The invention relates to the technical field of micropore filling, in particular to a micropore filling method based on a small-size quaternary ammonium salt single additive.
Background
Through Silicon Vias (TSV) are core interconnection structures of chip three-dimensional packaging technology, and usually a deep hole etching method is adopted to obtain a micro-hole blind hole, and then copper is used as a filler to form a micro-channel interconnection structure in a copper electroplating manner. TSVs are typically several microns to tens of microns in diameter, with aspect ratios typically of 5: 1-10: 1, the aspect ratio under special scenes can be as high as 20: 1. due to the limitation of the deep-pore structure, the TSV has a huge challenge in the electroplating filling process, and filling defects such as holes and gaps are easily formed, so that the manufacturing yield of the TSV is low, the quality of the TSV is poor, and the cost of the TSV is too high (about 40% of the whole TSV manufacturing process).
Because the concentration field distribution in the micropores is uneven, the components of each plating solution present a concentration gradient in the micropores, namely the concentration at the bottom of the micropores is lower than that at the opening. Because the concentration of the copper ions at the TSV hole opening is greater than that of the hole bottom, the growth rate of electroplated copper at the hole opening is greater than that of the hole bottom according to Faraday's law, and therefore after the hole is sealed through electroplating, a region at the bottom is still not filled through electroplating, and filling defects are formed. Currently, the industry generally employs the addition of suppressor additives to the plating bath to suppress orifice plating growth, which achieves defect-free filling when the orifice plating growth rate is slower relative to the bottom of the hole. Meanwhile, in order to increase the plating rate difference between the hole bottom and the hole opening, a plating accelerating additive is usually added into the plating solution to increase the plating growth rate of the hole bottom, thereby achieving a better defect-free filling effect. In conventional TSV filling plating solutions, additives such as suppressor, leveler and accelerator are typically added to improve TSV filling. By means of the competitive adsorption relationship among the three additives, the inhibitor usually acts on the surface and the orifice to play a strong inhibition role; the leveling agent is arranged on the inner side wall of the hole and plays a weaker inhibiting role; the accelerator acts on the bottom of the hole and plays a role in weak acceleration.
However, the conventional micropore filling electroplating additive system has the following disadvantages:
(1) the additives in the electroplating solution are of various types and difficult to regulate and control
The electroplating solution of the traditional additive system comprises three additives of an inhibitor, a leveling agent and an accelerator besides the components of the base solution, and the three additives have very complex competitive adsorption relationship. In the process of preparing the electroplating solution, the whole body is usually pulled to move, so that the formulation of the specific electroplating solution required by preparing micropores with various sizes is particularly difficult. A large amount of experiments and analyses are required to find out a relatively suitable ratio. Moreover, due to the complexity of the relevant action relationship among various additives, the regularity and the mobility of the formula are not strong, so that the regulation and control of the electroplating solution are difficult.
(2) Poor filling effect of micropores
The traditional additive system has good effect in TSV filling with low depth-to-width ratio, but filling defects are difficult to avoid in TSV filling with high depth-to-width ratio. With the decreasing size and increasing aspect ratio of microporous interconnection structures in recent years, the conventional additive systems have been unable to meet the technical requirements of the industry. The expression is as follows: 1) the macromolecular inhibitor with strong inhibition performance is often poor in transport capacity (such as PEG, PEI, Mr more than 5000), and cannot be effectively transported to a deep area to inhibit the growth of electroplated copper; 2) the small molecule leveling agent with strong transportation capability is poor in inhibition performance (such as JGB, Mr 511), and although the small molecule leveling agent can be transported to the deep hole bottom area, the small molecule leveling agent cannot strongly inhibit the growth of electroplated copper in the deep micropore area. Thereby failing to avoid formation of defects at the bottom of the high depth ratio micro-holes.
(3) Low efficiency and high cost
The low electroplating efficiency of the traditional additive system is firstly reflected in that the micropore filling process is too slow, and micropores with the diameter of 20 mu m and the depth of more than 120 mu m usually need several hours or even tens of hours to be filled. The main reason for this phenomenon is that the degree of inhibition on the aperture and the sidewall is insufficient, so that only the process current is reduced and the plating rate is slowed down to compensate (the inhibition effect is strong under the condition of low current), resulting in too slow filling rate.
On the other hand, due to the above disadvantages of the conventional additive system electroplating solution, a great amount of labor, material and time costs are consumed in the micropore electroplating filling process, so that the micropore filling process has low efficiency and high cost.
There is no current solution to such problems. Therefore, it is necessary to develop a plating solution system for filling micropores, which has a simpler formulation and higher micropore filling efficiency, to improve micropore filling quality and efficiency and to reduce process cost.
Disclosure of Invention
The invention provides a micropore filling method based on a small-size quaternary ammonium salt single additive, and aims to provide a single additive electroplating system which is easy to accurately regulate and control and realizes micropore filling with high quality and high efficiency.
In order to achieve the above object, the present invention provides a micropore filling method based on a small-sized quaternary ammonium salt single additive, comprising the steps of:
adding copper sulfate into deionized water, stirring, and then adjusting the pH to 0.8-2.0 by using dilute sulfuric acid to obtain electroplating base liquid;
adding small-size quaternary ammonium salt with anodic property into the electroplating base liquid obtained in the step (1) to obtain electroplating liquid;
pretreating a silicon wafer containing micropores, then immersing the silicon wafer into the electroplating solution obtained in the step 2, standing and soaking the silicon wafer to be used as a cathode, and immersing a pure copper wafer into the electroplating solution obtained in the step 2 to be used as an anode;
and (4) electrifying the anode and the cathode in the step (3) to carry out electroplating, and finishing filling the micropores of the silicon wafer.
Preferably, the concentration of the copper sulfate in the electroplating base solution is 80-280 g/L.
Preferably, the functional head group of the small-size quaternary ammonium salt is trimethyl ammonia or phenyl ammonia, and the tail group is 10-36 alkyl groups.
Preferably, the small size quaternary ammonium salt comprises one of dodecyltrimethylammonium bromide, octadecyltrimethylammonium bromide, and bromocetylpyridinium.
Preferably, in the step 2, the concentration of the small-sized quaternary ammonium salt in the electroplating solution is 0.01-1.5 g/L.
Preferably, in the step 3, the diameter of the micropores of the silicon wafer is 1-50 μm, and the depth is 10-200 μm.
Preferably, in step 3, the pretreatment is: and (3) cleaning the micropores of the silicon wafer by using dilute sulfuric acid and deionized water in sequence, and then performing suction filtration to remove air in the micropores.
Preferably, in the step 3, the soaking time is 8-12 min.
Preferably, in the step 4, the electroplating time is 30-200 min.
Preferably, a glass substrate containing micropores is used instead of the silicon wafer containing micropores.
The scheme of the invention has the following beneficial effects:
(1) compared with the traditional multi-additive electroplating system, the single-additive electroplating system provided by the invention has a simple formula and is easy to realize accurate regulation and control.
(2) Compared with the traditional inhibiting additives, the small-size quaternary ammonium salt inhibitor has stronger inhibiting performance and transport capacity, can effectively avoid the defect of filling micropores with high aspect ratio, and simultaneously improves the micropore filling efficiency.
(3) The new method provided by the invention has the advantages of better micropore electroplating filling effect, higher efficiency and lower cost.
Drawings
FIG. 1(a) shows the principle of the conventional multi-additive micro-hole filling electroplating system, and (b) shows the principle of the small-size quaternary ammonium salt single-additive micro-hole filling electroplating system.
FIG. 2 is a schematic structural diagram of a micropore filling apparatus according to the present invention.
FIG. 3 is an electron micrograph of a filled micropore according to example 1 of the present invention.
FIG. 4 is an electron micrograph of a filled micropore according to example 2 of the present invention.
FIG. 5 is an electron micrograph of the filling of micropores in a comparative example of the present invention.
[ description of reference ]
a 1-inhibitor; a 2-leveler; a 3-accelerator; b 1-small size quaternary ammonium salt inhibitor; 1-electroplating solution; 2-a silicon wafer; 21-micropores; 3-copper sheet; 4-precision power supply.
Detailed Description
In order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific embodiments.
Example 1
This example used cetylpyridinium bromide (HPB) as the sole plating additive for via plating fill with via sizes of 20 μm diameter and 200 μm depth.
The filling method comprises the following steps:
Adding copper sulfate into deionized water, fully stirring to prepare a solution with the copper sulfate concentration of 180g/L, and adjusting the pH value of the solution to 0.8 by using dilute sulfuric acid to form a stable electroplating base solution for later use;
weighing HPB, adding the HPB into the electroplating base solution obtained in the step (1) to enable the concentration of the HPB to be 0.4g/L, and obtaining electroplating solution 1 of a single inhibitor;
cleaning the surface of the silicon wafer 1 containing a large number of micropores 21 by using dilute sulfuric acid and deionized water in sequence; then, a vacuum filtration system is used for pumping out air in the micropores 21;
cleaning a pure copper sheet 3, and immersing the copper sheet 3 into the electroplating solution 1 in the step 2 under the clamping of an electrode clamp to be used as an anode of an electroplating system; immersing the processed silicon wafer 2 into the electroplating solution 1 in the step 2 under the clamping of an electrode clamp to be used as a cathode of an electroplating system; standing and soaking for 10min to fully convey the electroplating solution 1 to the insides of the micropores 21;
electrifying the anode and the cathode of the electroplating system in the step 3 by using a precise power supply to carry out electroplating;
and repeating the steps 3-4, wherein the electroplating time is respectively 30min, 45min and 60 min.
The silicon wafer 2 was subjected to slicing analysis, and the results are shown in FIG. 3.
Example 2
This example uses octadecyl trimethyl ammonium bromide (STAB) as the sole plating additive for a microvoid plating fill experiment, with a preferred microvoid size of 20 μm in diameter and 120 μm in depth.
The filling method comprises the following steps:
Adding copper sulfate into deionized water, fully stirring to prepare a solution with the copper sulfate concentration of 200g/L, and adjusting the pH value of the solution to 1.0 by using dilute sulfuric acid to form a stable electroplating base solution for later use;
weighing STAB, adding the STAB into the electroplating base solution obtained in the step 1 to enable the concentration of the STAB to be 0.35g/L, and obtaining electroplating solution 1 of a single inhibitor;
cleaning a pure copper sheet 3, and immersing the copper sheet 3 into the electroplating solution in the step 2 under the clamping of an electrode clamp to be used as an anode of an electroplating system; immersing the processed silicon wafer 2 into the electroplating solution 1 in the step 2 under the clamping of an electrode clamp to be used as a cathode of an electroplating system; standing and soaking for 10min to fully convey the electroplating solution 1 to the insides of the micropores 21;
electrifying the anode and the cathode of the electroplating system in the step 3 by using a precise power supply to carry out electroplating;
and repeating the steps 3-4, wherein the electroplating time is respectively 60min, 90min, 105min and 135 min.
The silicon wafer was subjected to slicing analysis, and the results are shown in FIG. 4.
The principle of the small-sized quaternary ammonium salt single additive micropore filling electroplating system in the embodiments 1-2 is shown in fig. 1 (b). The small-size quaternary ammonium salt inhibitor b1 generally comprises a functional head group (such as trimethyl ammonia and phenyl ammonia) and an alkyl chain, the molecular chain length is short (10-36 alkyl groups), and the molecular weight is generally below 600. On one hand, the small-size quaternary ammonium salt inhibitor b1 has stronger plating inhibition performance because the head group usually has stronger polarity and has higher adsorption rate (or coverage rate) on the cathode; on the other hand, compared with the traditional macromolecular inhibitor (with the molecular weight of more than 5000), the small-size quaternary ammonium salt inhibitor b1 has shorter tail group, smaller molecular weight and strong diffusion capability, thereby having stronger transport capability. Therefore, the small-size quaternary ammonium salt inhibitor b1 can effectively inhibit the quaternary ammonium salt from being transported to the bottom of the micropore and adsorbed on the side wall of the bottom, and the formation of an underfill defect is avoided.
Comparative example
In this example, the additive system commonly used in the industry is used for filling the micro-via electroplating, and as a comparative example, the principle of the micro-via filling electroplating system is shown in fig. 1 (a). In this example, a plating filling experiment of a micro-hole 21 was performed using PEG as an inhibitor a1, JGB as a leveler a2, and SPS as an accelerator a3, and the micro-hole size was 20 μm in diameter and 120 μm in depth.
The filling method comprises the following steps:
adding copper sulfate and sodium chloride into deionized water, stirring thoroughly, and then adjusting pH to 1.0 with dilute sulfuric acid to form stable electroplating base solution for use; wherein the concentration of copper sulfate is 200g/L, and the concentration of sodium chloride is 0.1 g/L;
weighing PEG, JGB and SPS, adding into the electroplating base solution obtained in the first step to obtain electroplating solution with PEG concentration of 0.5g/L, JGB and PEG concentration of 0.2g/L, SPS and PEG concentration of 0.1 g/L;
cleaning a pure copper sheet, and immersing the silicon wafer into the electroplating solution in the step 2 under the clamping of an electrode clamp to be used as an anode of an electroplating system; immersing the processed silicon wafer into the electroplating solution in the step 2 under the clamping of the electrode clamp to be used as a cathode of an electroplating system; standing and soaking for 10min to fully convey the electroplating solution to the insides of the micropores;
electrifying the anode and the cathode of the electroplating system in the step 3 by a precise power supply to carry out electroplating;
and (5) repeating the steps 3-4, wherein the electroplating time is 180min and 360min respectively.
The silicon wafer was subjected to slicing analysis, and the results are shown in FIG. 5.
The results show that, compared with the traditional inhibiting additives, the small-size quaternary ammonium salt inhibitor of the embodiment 1-2 has stronger inhibiting performance and transport capacity, can effectively avoid the defect of micropore filling with high aspect ratio, and simultaneously improves the micropore filling efficiency.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (10)
1. A micropore filling method based on small-size quaternary ammonium salt single additive is characterized by comprising the following steps:
step 1, preparing electroplating base liquid:
adding copper sulfate into deionized water, stirring, and then adjusting the pH to 0.8-2.0 by using dilute sulfuric acid to obtain electroplating base liquid;
step 2, preparing electroplating solution:
adding small-size quaternary ammonium salt with anodic property into the electroplating base liquid obtained in the step (1) to obtain electroplating liquid;
step 3, assembling an electrode:
pretreating a silicon wafer containing micropores, then immersing the silicon wafer into the electroplating solution obtained in the step 2, standing and soaking the silicon wafer to be used as a cathode, and immersing a pure copper wafer into the electroplating solution obtained in the step 2 to be used as an anode;
step 4, electroplating and filling:
and (4) electrifying the anode and the cathode in the step (3) to carry out electroplating, and finishing filling the micropores of the silicon wafer.
2. The method for filling micropores based on small-size quaternary ammonium salt single additive according to claim 1, wherein the concentration of copper sulfate in the electroplating base solution is 80-280 g/L.
3. The micropore filling method based on small-size quaternary ammonium salt single additive according to claim 1, wherein the small-size quaternary ammonium salt functional head group is trimethyl ammonia or phenyl ammonia, and the tail group is 10-36 alkyl groups.
4. The method of claim 1, wherein the small size quaternary ammonium salt comprises one of dodecyl trimethyl ammonium bromide, octadecyl trimethyl ammonium bromide, and cetyl pyridinium bromide.
5. The method for filling micropores based on small-size quaternary ammonium salt single additive in accordance with claim 1, wherein in the step 2, the concentration of small-size quaternary ammonium salt in the electroplating solution is 0.01-1.5 g/L.
6. The method for filling micropores based on small-size quaternary ammonium salt single additive in claim 1, wherein in the step 3, the diameter of the micropores of the silicon wafer is 1-50 μm, and the depth is 10-200 μm.
7. The method for filling micropores based on small-size quaternary ammonium salt single additive according to claim 1, wherein in the step 3, the pretreatment is: and (3) cleaning the micropores of the silicon wafer by using dilute sulfuric acid and deionized water in sequence, and then performing suction filtration to remove air in the micropores.
8. The method for filling micropores based on small-size quaternary ammonium salt single additive in claim 1, wherein in the step 3, the soaking time is 8-12 min.
9. The method for filling micropores based on small-size quaternary ammonium salt single additive in accordance with claim 1, wherein in the step 4, the electroplating time is 30-200 min.
10. The method for filling micropores based on small-size quaternary ammonium salt single additive according to claim 1, characterized in that a glass substrate containing micropores is used instead of a silicon wafer containing micropores.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010760001.1A CN111778545A (en) | 2020-07-31 | 2020-07-31 | Micropore filling method based on small-size quaternary ammonium salt single additive |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010760001.1A CN111778545A (en) | 2020-07-31 | 2020-07-31 | Micropore filling method based on small-size quaternary ammonium salt single additive |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111778545A true CN111778545A (en) | 2020-10-16 |
Family
ID=72765595
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010760001.1A Pending CN111778545A (en) | 2020-07-31 | 2020-07-31 | Micropore filling method based on small-size quaternary ammonium salt single additive |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111778545A (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108118372A (en) * | 2017-12-22 | 2018-06-05 | 广州美迪斯新材料有限公司 | A kind of high dispersive acidic copper plating additive and preparation method and application |
-
2020
- 2020-07-31 CN CN202010760001.1A patent/CN111778545A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108118372A (en) * | 2017-12-22 | 2018-06-05 | 广州美迪斯新材料有限公司 | A kind of high dispersive acidic copper plating additive and preparation method and application |
Non-Patent Citations (1)
| Title |
|---|
| HOUYA WU等: "Inhibition Effect of CTAB on Electrodeposition of Cu in Micro Via: Experimental and MD Simulation Investigations", 《JOURNAL OF THE ELECTROCHEMICAL SOCIETY》 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR101750664B1 (en) | Additive c capable of changing microvia-filling method by tsv copper plating, and electroplating solution containing same | |
| JP6012723B2 (en) | Copper plating method | |
| CN103572336B (en) | A kind of PCB blind hole copper electroplating solution and preparation method thereof and electro-plating method | |
| KR101627390B1 (en) | High speed copper plating bath | |
| US20160190007A1 (en) | A method for microvia filling by copper electroplating with tsv technology for 3d copper interconnection at high aspect ratio | |
| CN103103585B (en) | A kind of high speed salient point electro-plating method for copper-connection | |
| US20140299476A1 (en) | Electroplating method | |
| US20080087549A1 (en) | Additive For Copper Plating And Process For Producing Electronic Circiut Substrate Therewith | |
| CN112899736A (en) | PCB high-longitudinal-transverse-through-hole electro-coppering additive and preparation method thereof | |
| KR20120026462A (en) | By-product mitigation in through-silicon-via plating | |
| CN111058066A (en) | Application of sodium polydithio-ethane sulfonate as accelerator and electroplating solution containing sodium polydithio-ethane sulfonate | |
| CN115074789B (en) | Circuit board blind hole rapid filling electrolytic copper plating solution and rapid filling method | |
| CN114381769B (en) | Synthesis method and application of overspeed hole-filling copper plating leveling agent | |
| CN103484908B (en) | Electrochemical copper deposition method of TSV | |
| CN110642731A (en) | Leveling agent for blind hole full-copper electroplating, preparation method thereof and electroplating solution | |
| TWI499697B (en) | Wafer pretreatment for copper electroplating | |
| CN112030203A (en) | Through hole electroplating filling method and preparation method of printed circuit board | |
| CN113930813B (en) | Electro-coppering solution applied to wafer-level packaging and electroplating process thereof | |
| KR102381835B1 (en) | Anode for electrolytic copper plating and electrolytic copper plating apparatus using same | |
| CN111778545A (en) | Micropore filling method based on small-size quaternary ammonium salt single additive | |
| KR101840436B1 (en) | electrolytic copper solution and copper plating method using the electrolytic copper solution | |
| Koo et al. | Electrochemical process for 3D TSV without CMP and lithographic processes | |
| JP2017503929A (en) | Copper electrodeposition | |
| CN115976584A (en) | Copper electroplating solution suitable for filling ultra-deep hole TSV and copper electroplating process thereof | |
| CN110808229B (en) | Method for filling silicon-based high-aspect-ratio micro-nano through hole |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20201016 |
|
| RJ01 | Rejection of invention patent application after publication |