阅读说明：本技术 引线框架用逆流水洗的电镀工艺 (Electroplating process of countercurrent washing for lead frame ) 是由 任志军 秦小波 段升红 刘琪 于 2021-11-22 设计创作，主要内容包括：本发明涉及导电线框的电镀工艺技术领域,具体涉及一种引线框架用逆流水洗的电镀工艺。所述的引线框架用逆流水洗的电镀工艺,包括以下步骤：预水洗→显影→一级逆流水洗→预镀铜→二级逆流水洗→镀银→三级逆流水洗→烘干,新鲜水流入一级逆流水洗,一级逆流水洗流入一级逆流水洗,二级逆流水洗流入三级逆流水洗,三级逆流水洗与预水流直排,并且一级逆流水洗、一级逆流水洗、三级逆流水洗按照依次降低的方式成阶梯状分布。本发明提供一种引线框架用逆流水洗的电镀工艺,解决了引线框的电镀工艺中清洗中的用水量大,电镀废水产生量大,引线框架清洗较差问题。(The invention relates to the technical field of electroplating processes of conductive wire frames, in particular to an electroplating process for countercurrent washing of a lead frame. The electroplating process of the lead frame by countercurrent washing comprises the following steps: pre-washing → developing → first-stage countercurrent washing → pre-copper plating → second-stage countercurrent washing → silver plating → third-stage countercurrent washing → drying, wherein fresh water flows into the first-stage countercurrent washing, the first-stage countercurrent washing flows into the first-stage countercurrent washing, the second-stage countercurrent washing flows into the third-stage countercurrent washing, the third-stage countercurrent washing and the pre-water flow are directly discharged, and the first-stage countercurrent washing, the first-stage countercurrent washing and the third-stage countercurrent washing are distributed in a stepped manner in a sequentially decreasing manner. The invention provides an electroplating process for lead frame by countercurrent washing, which solves the problems of large water consumption, large electroplating wastewater generation amount and poor lead frame cleaning in the electroplating process of lead frame.)

1. The electroplating process of the countercurrent washing for the lead frame is characterized by comprising the following steps of: the method comprises the following steps: pre-washing → developing → first-stage countercurrent washing → pre-copper plating → second-stage countercurrent washing → silver plating → third-stage countercurrent washing → drying, wherein fresh water flows into the first-stage countercurrent washing, the first-stage countercurrent washing flows into the first-stage countercurrent washing, the second-stage countercurrent washing flows into the third-stage countercurrent washing, the third-stage countercurrent washing and the pre-water flow are directly discharged, and the first-stage countercurrent washing, the first-stage countercurrent washing and the third-stage countercurrent washing are distributed in a stepped manner in a sequentially decreasing manner.

2. The plating process of lead frame with counter current water washing according to claim 1, characterized in that: the method comprises the following steps:

(1) pre-washing: a DI spray water washing mode is adopted, and the water washing pressure is 4-5 Psi;

(2) and (3) developing: developing the unexposed dry film, and retaining the exposed dry film;

(3) primary countercurrent water washing: a DI spray water washing mode is adopted, and the water washing pressure is 9-10 Psi;

(4) pre-copper plating: at normal temperature, the thickness of the copper plating is 0.2-0.3 μm, the pH of the plating solution is 9-11, the current density is 0.8-1.3Asd, and the copper content is 30-45 g/L;

(5) secondary countercurrent water washing: a DI spray water washing mode is adopted, and the water washing pressure is 12-13 Psi;

(6) silver plating: at normal temperature, the thickness of silver plating is 1.5-8.9 μm, the pH of the plating solution is 9-11, the specific gravity of the plating solution is 17-28, and the silver content is 50-60 g/L;

(7) three-stage countercurrent water washing: a DI spray water washing mode is adopted, and the water washing pressure is 14-15 Psi;

(8) and (5) drying.

3. The plating process of lead frame with countercurrent water washing according to claim 2, characterized in that: the development is to develop the unexposed dry film by using a sodium carbonate solution, and the exposed dry film is reserved, wherein the concentration of a developing solution is 5-20g/L, the development temperature is 20-30 ℃, and the development speed is 3-5 m/min.

4. The plating process of lead frame with countercurrent water washing according to claim 2, characterized in that: the water flow speed of the pre-washing, the first-stage countercurrent washing, the second-stage countercurrent washing and the third-stage countercurrent washing is 5-6L/min.

5. The plating process of lead frame with countercurrent water washing according to claim 2, characterized in that: the drying temperature is 100-120 ℃, and the drying speed is 2-4 m/min.

6. The plating process of lead frame with countercurrent water washing according to claim 2, characterized in that: the fan-shaped nozzles are adopted for water washing, primary countercurrent water washing, secondary countercurrent water washing and tertiary countercurrent water washing.

Technical Field

The invention relates to the technical field of electroplating processes of lead frames, in particular to an electroplating process for countercurrent washing of lead frames.

Background

With the increasing competition of the global semiconductor industry, all the technical strength countries in the world strive for research and development of the lead frame which belongs to the complete semiconductor industry, the lead frame is used as a supporting frame of a semiconductor chip and is an important branch of the semiconductor industry, in the manufacturing process of the lead frame, an electroplating process is an important process, the electroplating process needs to be plated with a clean and high-compactness single plating layer or a composite plating layer with proper thickness at a specified position to meet the requirement of a wire bonding test of a wafer, in the electroplating process, the washing effect among medicine cylinders directly influences the concentration of impurity ions in the medicine cylinders and the surface cleanliness of lead frame products, the wire bonding effect and stability of a client are directly influenced, in addition, the water consumption is large in the implementation process of the electroplating process, the cleanliness degree of the lead frame products is insufficient, and the use of subsequent processes is influenced.

CN104900536A discloses a surface treatment method for a semiconductor lead frame, which comprises ultrasonic degreasing, electrolytic degreasing, water washing, sulfuric acid neutralization and activation, water washing, copper electroplating, water washing, acid neutralization, water washing, copper protection, water washing, hot water washing and drying, wherein the purpose of protection is achieved mainly by a plated copper protective film, the operation steps are complex, and the water consumption is large.

CN102534711B discloses a water-saving method in a metal plate electroplating cleaning process, which utilizes the processes of uncoiling, alkali cleaning, brushing, alkali flushing, straightening, acid cleaning, acid flushing, electroplating and coiling, and utilizes acid-base flushing water to achieve the purpose of water saving.

CN209722349U discloses tertiary wash bowl is electroplated to water conservation formula, this wash bowl has set up one-level wash bowl, second grade wash bowl, tertiary wash bowl, first overflow mouth, second water pump and microporous membrane filter, and the sewage of one-level wash bowl can supply the second grade wash bowl to use, and the second grade wash bowl uses and can supply the one-level wash bowl to use, and microporous membrane filter can carry out filtration treatment to final exhaust sewage, can carry out filtration treatment to final sewage when realizing the water conservation purpose, avoids the direct discharge polluted environment.

Disclosure of Invention

The invention aims to solve the technical problem of providing an electroplating process for lead frame by countercurrent washing, which solves the problems of large water consumption, large electroplating wastewater generation amount and poor lead frame cleaning in the electroplating process of the lead frame.

The electroplating process of the lead frame by countercurrent washing comprises the following steps: pre-washing → developing → first-stage countercurrent washing → pre-copper plating → second-stage countercurrent washing → silver plating → third-stage countercurrent washing → drying, wherein fresh water flows into the first-stage countercurrent washing, the first-stage countercurrent washing flows into the first-stage countercurrent washing, the second-stage countercurrent washing flows into the third-stage countercurrent washing, the third-stage countercurrent washing and the pre-water flow are directly discharged, and the first-stage countercurrent washing, the first-stage countercurrent washing and the third-stage countercurrent washing are distributed in a stepped manner in a sequentially decreasing manner.

The electroplating process of the lead frame by countercurrent washing comprises the following steps:

(1) pre-washing: a DI spray water washing mode is adopted, and the water washing pressure is 4-5 Psi;

(2) and (3) developing: developing the unexposed dry film, and retaining the exposed dry film;

(3) primary countercurrent water washing: a DI spray water washing mode is adopted, and the water washing pressure is 9-10 Psi;

(4) pre-copper plating: at normal temperature, the thickness of the copper plating is 0.2-0.3 μm, the pH of the plating solution is 9-11, the current density is 0.8-1.3Asd, and the copper content is 30-45 g/L;

(5) secondary countercurrent water washing: a DI spray water washing mode is adopted, and the water washing pressure is 12-13 Psi;

(6) silver plating: at normal temperature, the thickness of silver plating is 1.5-8.9 μm, the pH of the plating solution is 9-11, the specific gravity of the plating solution is 17-28, and the silver content is 50-60 g/L;

(7) three-stage countercurrent water washing: a DI spray water washing mode is adopted, and the water washing pressure is 14-15 Psi;

(8) and (5) drying.

Preferably, the developing is to develop the unexposed dry film by using a sodium carbonate solution, and the exposed dry film is retained, wherein the concentration of the developing solution is 5-20g/L, the developing temperature is 20-30 ℃, and the developing speed is 3-5 m/min.

Preferably, the water flow speed of the pre-washing, the first-stage countercurrent washing, the second-stage countercurrent washing and the third-stage countercurrent washing is 5-6L/min, and ultrapure water (DI water) is used for washing the lead frame in a spraying mode, the DI water is used for adsorbing calcium ions/chloride ions/magnesium ions and the like of anions and cations of a physically large-particle-free water body through resin, and the treated DI water can meet the application of a conductive wire frame.

Preferably, the drying temperature is 100-120 ℃, and the drying speed is 2-4 m/min.

Preferably, fan-shaped nozzles are adopted for water washing, primary counter-current water washing, secondary counter-current water washing and tertiary counter-current water washing.

Compared with the prior art, the invention has the following beneficial effects:

(1) according to the electroplating process for the lead frame by using the countercurrent washing, the lead frame product with high purity is prepared by using a DI washing mode, the water for electroplating is reduced, and the wastewater discharge is reduced;

(2) the electroplating process of the lead frame by using the countercurrent washing saves tap water and DI water treated by complex water;

(3) the electroplating process of the lead frame by using the countercurrent washing reduces the environmental pollution, greatly reduces the discharge amount of electroplating sewage and reduces the risk of environmental pollution;

(4) the electroplating process of the lead frame with the countercurrent washing reduces product pollution, improves the yield of lead frame products, and saves the consumption of noble metals such as copper, silver, gold and the like.

Detailed Description

The invention provides an electroplating process for countercurrent washing of a lead frame, and the electroplating process can be realized by appropriately improving process parameters by taking the contents of the electroplating process as reference by a person skilled in the art. It is expressly intended that all such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the scope and ambit of the invention. While the process of the present invention has been described in terms of preferred embodiments, it will be apparent to those skilled in the art that variations and appropriate modifications and combinations of the process of the present invention may be made to implement and use the techniques of the present invention without departing from the spirit and scope of the invention.

The electroplating process of the lead frame by countercurrent washing comprises the following steps: pre-washing → developing → first-stage countercurrent washing → pre-copper plating → second-stage countercurrent washing → silver plating → third-stage countercurrent washing → drying, wherein fresh water flows into the first-stage countercurrent washing, the first-stage countercurrent washing flows into the first-stage countercurrent washing, the second-stage countercurrent washing flows into the third-stage countercurrent washing, the third-stage countercurrent washing and the pre-water flow are directly discharged, and the first-stage countercurrent washing, the first-stage countercurrent washing and the third-stage countercurrent washing are distributed in a stepped manner in a sequentially decreasing manner.

The electroplating process of the lead frame by countercurrent washing comprises the following steps:

(1) pre-washing: a DI spray water washing mode is adopted, and the water washing pressure is 4-5 Psi;

(2) and (3) developing: developing the unexposed dry film, and retaining the exposed dry film;

(3) primary countercurrent water washing: a DI spray water washing mode is adopted, and the water washing pressure is 9-10 Psi;

(4) pre-copper plating: at normal temperature, the thickness of the copper plating is 0.2-0.3 μm, the pH of the plating solution is 9-11, the current density is 0.8-1.3Asd, and the copper content is 30-45 g/L;

(5) secondary countercurrent water washing: a DI spray water washing mode is adopted, and the water washing pressure is 12-13 Psi;

(6) silver plating: at normal temperature, the thickness of silver plating is 1.5-8.9 μm, the pH of the plating solution is 9-11, the specific gravity of the plating solution is 17-28, and the silver content is 50-60 g/L;

(7) three-stage countercurrent water washing: a DI spray water washing mode is adopted, and the water washing pressure is 14-15 Psi;

(8) and (5) drying.

Further, the developing step is to develop the unexposed dry film by using a sodium carbonate solution, and to retain the exposed dry film, wherein the concentration of a developing solution is 5-20g/L, the developing temperature is 20-30 ℃, and the developing speed is 3-5 m/min;

further, the water flow speed of the pre-washing, the first-stage countercurrent washing, the second-stage countercurrent washing and the third-stage countercurrent washing is 5-6L/min.

Further, the drying temperature is 100-120 ℃, and the drying speed is 2-4 m/min.

Furthermore, fan-shaped nozzles are adopted for water washing, primary countercurrent water washing, secondary countercurrent water washing and tertiary countercurrent water washing.

In order to further illustrate the present invention, the electroplating process of the lead frame with counter-current water washing according to the present invention will be described in detail with reference to the following examples.

Example 1

The electroplating process of the lead frame by countercurrent washing comprises the following steps:

(1) pre-washing: adopting a DI spray washing mode and fan-shaped nozzles, wherein 6 washing spray pipes are adopted, the washing pressure is 4Psi, and the water flow speed is 5L/min;

(2) and (3) developing: developing the unexposed dry film by using a sodium carbonate solution, and keeping the exposed dry film, wherein the concentration of a developing solution is 5g/L, the developing temperature is 20 ℃, and the developing speed is 3 m/min;

(3) primary countercurrent water washing: adopting a DI spray washing mode and fan-shaped nozzles, wherein 6 washing spray pipes are adopted, the washing pressure is 9Psi, and the water flow speed is 5L/min;

(4) pre-copper plating: at normal temperature, the thickness of the copper plating is 0.2 mu m, the pH of the plating solution is 9, the current density is 0.8Asd, and the copper content is 30 g/L;

(5) secondary countercurrent water washing: adopting a DI spray washing mode and fan-shaped nozzles, wherein 6 washing spray pipes are adopted, the washing pressure is 12Psi, and the water flow speed is 5L/min;

(6) silver plating: at normal temperature, the thickness of silver plating is 1.5 mu m, the pH of the plating solution is 9, the specific gravity of the plating solution is 17, and the silver content is 50 g/L;

(7) three-stage countercurrent water washing: adopting a DI spray water washing mode and fan-shaped nozzles, wherein the number of water washing spray pipes is 6, the water washing pressure is 14Psi, and the water flow speed is 5L/min;

(8) drying: the drying temperature is 100 ℃, and the drying speed is 2 m/min.

The lead frame is washed by counter-current water, the water consumption in the process is 6.02LPM, and the water washing effect is that the inorganic salt on the surface of the lead frame contains 120ng/cm²Product stain loss was 2.5%.

Example 2

The electroplating process of the lead frame by countercurrent washing comprises the following steps:

(1) pre-washing: adopting a DI spray water washing mode and a fan-shaped nozzle, wherein the water washing pressure is 5Psi, the number of water washing spray pipes is 6, and the water flow speed is 6L/min;

(2) and (3) developing: developing the unexposed dry film by using a sodium carbonate solution, and keeping the exposed dry film, wherein the concentration of a developing solution is 15g/L, the developing temperature is 25 ℃, and the developing speed is 4 m/min;

(3) primary countercurrent water washing: adopting a DI spray washing mode and fan-shaped nozzles, wherein 6 washing spray pipes are adopted, the washing pressure is 9Psi, and the water flow speed is 6L/min;

(4) pre-copper plating: at normal temperature, the thickness of the copper plating is 0.3 mu m, the pH of the plating solution is 10, the current density is 1.0Asd, and the copper content is 40 g/L;

(5) secondary countercurrent water washing: adopting a DI spray washing mode and fan-shaped nozzles, wherein 6 washing spray pipes are adopted, the washing pressure is 13Psi, and the water flow speed is 6L/min;

(6) silver plating: at normal temperature, the thickness of silver plating is 3.5 mu m, the pH of the plating solution is 10, the specific gravity of the plating solution is 20, and the silver content is 55 g/L;

(7) three-stage countercurrent water washing: adopting a DI spray water washing mode and fan-shaped nozzles, wherein 6 washing spray pipes are adopted, the washing pressure is 14Psi, and the water flow speed is 6L/min;

(8) drying: the drying temperature is 110 ℃, and the drying speed is 3 m/min.

The lead frame is washed by counter-current water, the water consumption in the process is 5.89LPM, and the water washing effect is that the inorganic salt on the surface of the lead frame contains 112ng/cm²Product stain loss was 2.0%.

Example 3

The electroplating process of the lead frame by countercurrent washing comprises the following steps:

(1) pre-washing: adopting a DI spray washing mode and fan-shaped nozzles, wherein 6 washing spray pipes are adopted, the washing pressure is 5Psi, and the water flow speed is 6L/min;

(2) and (3) developing: developing the unexposed dry film by using a sodium carbonate solution, and keeping the exposed dry film, wherein the concentration of a developing solution is 20g/L, the developing temperature is 30 ℃, and the developing speed is 5 m/min;

(3) primary countercurrent water washing: adopting a DI spray washing mode and fan-shaped nozzles, wherein 6 washing spray pipes are adopted, the washing pressure is 10Psi, and the water flow speed is 6L/min;

(4) pre-copper plating: at normal temperature, the thickness of the copper plating is 0.3 mu m, the pH of the plating solution is 11, the current density is 1.3Asd, and the copper content is 45 g/L;

(5) secondary countercurrent water washing: adopting a DI spray washing mode and fan-shaped nozzles, wherein 6 washing spray pipes are adopted, the washing pressure is 13Psi, and the water flow speed is 6L/min;

(6) silver plating: at normal temperature, the thickness of silver plating is 8.9 μm, the pH of the plating solution is 11, the specific gravity of the plating solution is 28, and the silver content is 60 g/L;

(7) three-stage countercurrent water washing: adopting a DI spray water washing mode and a fan-shaped nozzle, wherein the water washing pressure is 15Psi, the number of water washing spray pipes is 6, and the water flow speed is 6L/min;

(8) drying: the drying temperature is 120 ℃, and the drying speed is 4 m/min.

The lead frame is washed by counter-current water, the water consumption in the process is 5.44LPM, and the water washing effect is that the inorganic salt on the surface of the lead frame contains 100ng/cm²Product stain loss was 1.5%.

Comparative example 1

An electroplating process for a conductive wire frame, comprising the steps of:

(1) pre-washing: adopting a DI spray washing mode and a conical nozzle, wherein 9 washing spray pipes are adopted, the washing pressure is 20Psi, and the water flow speed is 6L/min;

(2) and (3) developing: developing the unexposed dry film by using a sodium carbonate solution, and keeping the exposed dry film, wherein the concentration of a developing solution is 20g/L, the developing temperature is 30 ℃, and the developing speed is 5 m/min;

(3) primary flow water washing: adopting a DI spray washing mode and a conical nozzle, wherein 9 washing spray pipes have washing pressure of 20Psi and water flow speed of 6L/min;

(4) pre-copper plating: at normal temperature, the thickness of the copper plating is 0.3 mu m, the pH of the plating solution is 11, the current density is 1.3Asd, and the copper content is 45 g/L;

(5) secondary flow water washing: adopting a DI spray washing mode and a conical nozzle, wherein 9 washing spray pipes are adopted, the washing pressure is 20Psi, and the water flow speed is 6L/min;

(6) silver plating: at normal temperature, the thickness of silver plating is 3.0 μm, the pH of the plating solution is 11, the specific gravity of the plating solution is 28, and the silver content is 60 g/L;

(7) third-stage flowing water washing: adopting a DI spray washing mode and a conical nozzle, wherein 9 washing spray pipes are adopted, the washing pressure is 20Psi, and the water flow speed is 6L/min;

(8) drying: the drying temperature is 120 ℃, and the drying speed is 4 m/min.

Through the electroplating process of the conductive wire frame, the water consumption in the process is 16.32LPM, and the water washing effect is that the inorganic salt on the surface of the lead frame contains 500ng/cm²Product stain loss was 5.0%.

As can be seen from the comparative example 1 and the examples 1 to 3, the water consumption of the electroplating process method of the comparative example 1 reaches 16.32LPM, and compared with the electroplating process in the embodiment of the invention, the water consumption is more than 2.5 times, which also increases great difficulty in sewage treatment; and the inorganic salt content on the surface of the conductive wire frame after water washing is still as high as 500ng/cm²The stain loss of the product is as high as 5.0 percent, and the electroplating process of the conductive wire frame provided by the invention has the advantages of low water consumption, low inorganic salt content on the surface of the product washed by water and small stain loss of the product.

Of course, the foregoing is only a preferred embodiment of the invention and should not be taken as limiting the scope of the embodiments of the invention. The present invention is not limited to the above examples, and equivalent changes and modifications made by those skilled in the art within the spirit and scope of the present invention should be construed as being included in the scope of the present invention.