JPH01129982A - Recycling method and etching method of ferric chloride etchant - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] The present invention relates to a method for regenerating and etching a ferric chloride etchant.

[Prior Art] Methods for regenerating aged ferric chloride etchant include adding an oxidizing agent such as hydrogen peroxide or sodium hypochlorite, contacting it with chlorine gas, or electrolysis. There is a way.

The method of adding hydrogen peroxide has poor reaction efficiency, and a large amount must be added in order to achieve the desired regeneration. Therefore, the etch end is likely to be considerably diluted, which is undesirable since it will adversely affect etching performance. This method is quite problematic in terms of cost.

The method of using sodium hypochlorite is dangerous because it generates chlorine gas when added as a concentrated solution. Therefore, the etchant must be added in a diluted state, resulting in the problem of diluting the etchant as in the case of hydrogen peroxide. In addition, salt accumulates, which is inconvenient for repeated regeneration methods.

Similarly, a method using a chlorate such as sodium chlorate is also unfavorable in terms of accumulation of alkali salts.

As described above, the method of oxidation regeneration using chemicals is not suitable for the method of the present invention, in which a regeneration device and an etching device are connected to continuously regenerate and utilize the etchant.

Although the regeneration method using chlorine gas is the most efficient and ideal method in terms of chemical reactions, chlorine gas is extremely harmful and poses problems in terms of the working environment and pollution.

The electrolytic method does not have the problems of the methods explained above, and it is an ideal method in terms of regeneration because it allows the metal dissolved by etching to be precipitated and separated, but it lacks stability and is difficult to maintain. Currently, there are problems and it is not put into practical use.

Although conventional regeneration methods have been described, there are problems with any of the methods when it comes to continuously and safely regenerating the etchant and supplying it to an etching device for environmental use.

[Object of the Invention] An object of the present invention is to eliminate the drawbacks of the conventional methods described above, and to provide a method for inexpensively and safely regenerating an edger, and an etching method using the method.

Summary of the Invention The summary of the invention is to utilize air oxidation in the presence of nitric acid as a method to regenerate ferric chloride etchant.

As a result, an etchant with good properties without any safety issues can be regenerated and recycled.

The amount of nitric acid added is not particularly specified, but if it is in a small amount, the catalytic effect will be weak, and if it is humane, it may damage some resists. , affects etching properties.

Common sense suggests that a range of 5 to 500 g of nitrate radicals is considered to be appropriate for 1 K9 of iron in edgeants.

For air oxidation, a temperature range of 75 to 80° C. is efficient and desirable, but the heat resistance of pumps and the like is limited in the piping area of the circulation route. - Inside the membrane, the heat resistance of high-density polyethylene is limited to 50-70°C, but in some cases,
It is also possible to increase the air oxidation temperature by lining the inner surface of the piping used in the circulation route with a highly corrosion-resistant material such as titanium or an organic material with high heat and high chemical resistance such as Teflon. be.

[Example] Fig. 1 is a system diagram showing the etching method of the present invention, in which 1 is an air oxidizer main body, 1a is a mist removal device, and 1b is a system diagram showing the etching method of the present invention.
is a spray, 1C is a filling material, 1d is a blower, 1e is a blower pipe, 1f is a heat insulator, 2 is a chemical addition tank body, 2e is a stirrer, 2b is an oxidation-reduction electrometer, 2C is a specific gravity measurement sensor, 2
d is an electrometer for measuring acid concentration, 2e is a chemical supply pipe, 3 is an etching device, 4 is a pump, and 5 is a transport pipe.

In FIG. 1, the air oxidizer main body 1 includes a sprayer 1b
, a filling material 1C, and a blower 1d, a blower pipe 1e, a mist removing device 1a, and a pump 4. Pump 4 has a pressure of 50Kyf/aA.
1! /win (7) Has the ability to transport and ejects the etchant from spray 1b to the award certificate.

The temperature of the etchant is 60°C. Sending [41111d
Air is sent in at a rate of 1 m3/1 lin to oxidize the etchant. The oxidized etchant is transferred to the chemical addition tank 2, and the oxidation-reduction potentiometer 2b and specific gravity measurement sensor 2c
, appropriate hydrochloric acid and water are automatically added from the chemical supply pipe 2e based on the value measured by the acid concentration measuring electrometer 2d.

The amount of nitric acid is limited by chemical and chemical analysis to 30 to 50 g per 1 kg of iron in the etchant, and the inside of the chemical addition tank 2 is stirred by a stirrer 2a.

The chemically added etchant flows into the etching device 3 through the transport pipe 5 and is circulated again by the pump 4 to the spray 1b of the air oxidizer 1.

Under the conditions explained above, the dissolution bond to the etchant is 200
When a lead frame made of an alloy made of 58% iron and 42% nickel was continuously etched at a speed of 0/hour, the degree of aging of the etchant (the total number of iron in the etchant excluding divalent iron) was 0. It was possible to maintain the value within the range of 12 to 0.13, and sufficient practicality was recognized. If nitric acid is not added, the degree of aging increases and it is not possible to maintain the above degree of aging.

In this embodiment, the chemical addition tank 2 is placed before the etching device 3, but it may also be placed after the etching device 3.

[Effects of the Invention] The present invention establishes a safe etching method that allows etching to be carried out under conditions where the concentration of ferric chloride is kept constant without the presence of substances that interfere with etching such as alkali metals. be done.

[Brief explanation of the drawing]

FIG. 1 is a systematic diagram of the etching method of the present invention. 1: Air oxidizer main body, 1a: Mist removal device, 1b Nispray, 1C; filling, d: blower, 1e: Air pipe, 1f: Heat insulation material, 2: Chemical addition tank body, 2a: Stirrer, 2b: redox electrometer, 2C: specific gravity measurement sensor, 2d: acid concentration measuring electrometer, 2e: Chemical supply pipe, 3: Etch, Young device, 4: Pump, 5: Transport pipe.

Claims (2)

[Claims] (1) Ferric chloride, which is characterized by being regenerated by air oxidation in the presence of nitrate radicals in the ferric chloride etchant.
How to regenerate iron etchant. (2) An etching method characterized by using a device that can maintain the degree of aging of the etchant within a certain range by combining a reconditioning device according to the method described above and an etching device.