CN115261863A - A kind of metal particle corrosion solution and metal corrosion method for fast recovery diode - Google Patents

Abstract

The invention discloses a metal particle corrosive liquid and a metal corrosion method for a fast recovery diode in the technical field of fast recovery diodes. The metal corrosion method sequentially comprises the following steps: placing the photoetched wafer in an acid-washing basket, and performing primary metal corrosion treatment in a conventional manner; soaking the wafer subjected to the primary metal corrosion treatment in a metal particle corrosion solution, wherein the temperature of the metal particle corrosion solution is 18-22 ℃, the soaking time is 50-70s, and the pickling basket is continuously shaken during the soaking period to finish secondary corrosion; and (4) washing the wafer subjected to the secondary corrosion treatment by water, drying by spin-drying, and drying in a constant environment. The metal corrosion method carries out secondary corrosion on the basis of conventional corrosion, effectively solves the problem of residual metal particles on the surface of a product after corrosion through the specially-made metal particle corrosion solution, and ensures that the product cannot have the phenomenon of electric leakage mutation caused by the problem of the metal particles.

Description

Metal particle corrosion solution and metal corrosion method for fast recovery diode

technical field

The invention relates to the technical field of fast recovery diodes, in particular to a metal particle corrosion solution and a metal corrosion method for fast recovery diodes.

Background technique

At present, in the process of manufacturing fast recovery diodes, a metal corrosion process is required after the metal layer is prepared by evaporation and photolithography. The purpose of metal corrosion is to remove the exposed part of the underlying material in the photoresist micropattern after exposure and development, that is, to reproduce the same pattern as the photoresist on the underlying material.

After the metal corrosion treatment, the flushing and drying process is carried out according to the conventional process. However, after product testing, it was found that the leakage consistency between products was poor, and some products had abnormal leakage. In addition, through observation under a microscope, it was found that metal corrosion and some products after flushing treatment left a little metal particles in the corroded area, which could not be completely removed by the flushing process. During subsequent tests, the residual metal caused abnormal leakage.

Contents of the invention

The present application at least partly solves the above problems by providing a metal particle corrosion solution and a metal corrosion method for fast recovery diodes.

The embodiment of the present application provides a metal particle corrosion solution for fast recovery diodes, which includes water, hydrogen peroxide, ammonia water, glacial acetic acid, ethylene di The mixed solution of amine tetraacetic acid, wherein the mass ratio of water and ethylenediamine tetraacetic acid in the mixed solution of ethylenediamine tetraacetic acid is 40-66:1.

The beneficial effect of the above embodiment is that: the metal particle corrosion solution can effectively remove a little metal particles remaining in the corrosion area in the prior art, thereby reducing the abnormal leakage

On the basis of the foregoing embodiments, the present application can be further improved, specifically as follows:

In one of the embodiments of the present application, the metal particle corrosion solution also includes sodium hydroxide solution, and the water, hydrogen peroxide, ammonia water, glacial acetic acid, ethylenediaminetetraacetic acid mixed solution and sodium hydroxide solution have a corresponding volume ratio of 1: 0.7-0.8: 0.2-0.3: 0.2-0.3: 0.1-0.15: 0.1-0.15, wherein in the sodium hydroxide solution, the mass percent concentration of sodium hydroxide is 1.5-2.5%. Adding the sodium hydroxide solution can prevent discoloration of the chip after being soaked in the metal particle corrosion solution, and keep the metal color of the chip surface consistent.

In one of the embodiments of the present application, the corresponding volume ratio of the water, hydrogen peroxide, ammonia water, glacial acetic acid, ethylenediaminetetraacetic acid mixed solution and sodium hydroxide solution is 1:0.75:0.25:0.25:0.125:0.125, wherein , the mass ratio of water and EDTA in the EDTA mixture is 50:1, and in the sodium hydroxide solution, the mass percentage concentration of sodium hydroxide is 2%.

In one of the embodiments of the present application, the configuration method of the metal particle corrosion solution is as follows:

Mix water and ethylenediaminetetraacetic acid powder according to the above ratio to prepare an ethylenediaminetetraacetic acid mixed solution, and mix water and sodium hydroxide powder to prepare a sodium hydroxide solution;

Let the mixed solution of ethylenediaminetetraacetic acid and sodium hydroxide solution stand still for more than 1 hour;

Mix water, hydrogen peroxide, ammonia water, glacial acetic acid, and ethylenediaminetetraacetic acid mixture according to the above ratio, and then add sodium hydroxide solution to mix and prepare the metal particle corrosion solution.

The embodiment of the present application also provides a metal corrosion method for a fast recovery diode, which includes the following steps in sequence:

Place the wafer after photolithography in the pickling flower basket, and perform preliminary metal corrosion treatment in a conventional manner;

The wafer after preliminary metal corrosion treatment is soaked in the aforementioned metal particle corrosion solution, the temperature of the metal particle corrosion solution is 18-22°C, the soaking time is 50-70s, and the pickling flower basket is continuously shaken during the soaking period to complete the second secondary corrosion;

The wafer after the secondary etching treatment is rinsed with water and dried by drying, and then placed in a constant environment to dry.

The beneficial effects of the above embodiment are: on the basis of conventional corrosion, a tank of metal particle corrosion solution is added for secondary corrosion, which effectively solves the problem of metal particles remaining on the surface of the product after corrosion, and ensures that the product will not leak electricity due to metal particles. mutation phenomenon; at the same time, a drying step is added after the secondary corrosion to remove the water vapor brought by the product due to corrosion and flushing, so as to ensure the consistency of product leakage.

In one embodiment of the present application, during the secondary corrosion, the temperature of the metal particle corrosion solution is 18° C., and the immersion time is 60 s.

In one of the embodiments of the present application, the constant ambient temperature is 20° C., the humidity is 15%, and the drying time is 20-24 hours.

In one embodiment of the present application, the material of the pickling flower basket is Teflon, the pickling flower basket includes a mask and an H surface, and the pickling flower basket is provided with a plurality of through holes at intervals on the mask surface, so The inner diameter of the through hole gradually decreases from inside to outside. Optimizing the pickling flower basket by opening a bell-shaped through hole in the mask can effectively improve the difference in the amount of side corrosion between the metal corrosion sheets, achieve the effect of balancing the corrosion amount in the flower basket, ensure the consistency of product leakage, and reduce the Rework rates for metal corrosion.

One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

1. Carry out secondary corrosion on the basis of conventional corrosion, and effectively solve the problem of residual metal particles on the surface of the product after corrosion through the metal particle corrosion solution, so as to ensure that the product will not have sudden leakage caused by metal particles;

2. Add a drying step after the secondary corrosion to remove the water vapor brought by the product due to corrosion and flushing to ensure the consistency of product leakage;

3. By opening bell-shaped through holes in the mask to optimize the pickling flower basket, it can effectively improve the difference in the amount of side corrosion between the metal corrosion sheets, achieve the effect of balancing the amount of corrosion in the flower basket, and ensure the consistency of product leakage. Reduced rework rates for metal corrosion.

Description of drawings

In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings that need to be used in the description of the specific embodiments or the prior art. Throughout the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, elements or parts are not necessarily drawn in actual scale.

Fig. 1 is the step flowchart of the metal corrosion method of a kind of fast recovery diode in embodiment 2;

Fig. 2 is the structural representation of pickling flower basket in embodiment 3.

Among them, 1. Masked surface, 2. H surface, 3. Through hole.

Detailed ways

Below in conjunction with specific embodiment, further illustrate the present invention, it should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention, after reading the present invention, those skilled in the art will understand the various equivalent forms of the present invention All modifications fall within the scope defined by the appended claims of the present application.

It should be noted that like numerals and letters denote similar items in the following figures, therefore, once an item is defined in one figure, it does not require further definition and explanation in subsequent figures.

In describing the present invention, the schematic representations of the above terms are not necessarily referring to the same embodiment or example. Furthermore, the described specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in the present invention and features of different embodiments or examples under the condition of not contradicting each other.

The embodiments of the present application provide a metal particle corrosion solution and a metal corrosion method for fast recovery diodes to solve the problem in the prior art that a small amount of metal particles remain in the corrosion area, resulting in abnormal leakage of the product.

The technical solution in the embodiment of the present application is to solve the above problems, and the general idea is as follows:

Example 1:

A metal particle corrosion solution for fast recovery diodes, including water, hydrogen peroxide, ammonia water, glacial acetic acid, and ethylenediamine tetrachloride in a volume ratio of 1:0.7-0.8:0.2-0.3:0.2-0.3:0.1-0.15:0.1-0.15 Acetic acid mixture and sodium hydroxide solution, wherein the mass ratio of water to ethylenediaminetetraacetic acid in the EDTA mixture is 40-66:1, and the sodium hydroxide solution has a mass percent concentration of 1.5- 2.5%.

Among them, the preferred volume ratio of water, hydrogen peroxide, ammonia water, glacial acetic acid, ethylenediamine tetraacetic acid mixed solution and sodium hydroxide solution is 1:0.75:0.25:0.25:0.125:0.125. The preferred mass ratio of water and EDTA in the EDTA mixed solution is 50:1, and in the sodium hydroxide solution, the preferred mass percentage concentration of sodium hydroxide is 2%.

The metal particle corrosion solution with the above ratio can effectively remove metal particles such as Ag, Ti, Ni, Al, etc.

Specifically, the metal particle corrosion solution configuration method is as follows:

Mix water and ethylenediaminetetraacetic acid powder according to the above ratio to prepare an ethylenediaminetetraacetic acid mixed solution, and mix water and sodium hydroxide powder to prepare a sodium hydroxide solution;

Let the mixed solution of ethylenediaminetetraacetic acid and sodium hydroxide solution stand still for more than 1 hour;

Mix water, hydrogen peroxide, ammonia water, glacial acetic acid, and ethylenediaminetetraacetic acid mixture according to the above ratio, and then add sodium hydroxide solution to mix and prepare a metal particle corrosion solution.

It should be noted that the metal corrosion solution needs to be prepared and used immediately, and generally can only be used within 5 hours after the configuration is completed.

Example 2:

As shown in Figure 1, a metal corrosion method for a fast recovery diode comprises the following steps in turn:

S1: Preliminary corrosion: place the photoetched wafer in a pickling flower basket, and perform preliminary metal corrosion treatment in a conventional manner.

An example of the general method of preliminary corrosion that can be used is as follows: first put the wafer into the nitrifying acid mixed corrosion solution to corrode metal Ag and Ni, the corrosion time is 150-160s, after corrosion, put it into the water tank for 10 minutes, and then put it Put the product into the B solution (1:200=HF:H2O) to corrode metal Ti, the corrosion time is 30-35s, after the corrosion, flush with water for 10 minutes, after the flushing is completed, put the product into the Al corrosion solution to corrode metal Al , The corrosion time is 290-310s, flush with water for 20 minutes after corrosion, and complete the preliminary corrosion after flushing, after the preliminary corrosion, a small amount of granular metal will be oxidized or carbonized and remain.

S2: Secondary corrosion: soak the wafer after preliminary metal corrosion treatment in the metal particle corrosion solution as in Example 1, the temperature of the metal particle corrosion solution is 18-22°C, and the soaking time is 50-70s. Shake the pickling flower basket to complete the secondary corrosion.

Among them, the preferred temperature of the metal particle corrosion solution is 18°C, and the soaking time is 60s. If the temperature is too high, over-corrosion is prone to occur, that is, there are bumps on the edge of the ring, which is inconvenient to operate. Therefore, reducing the corrosion temperature and prolonging the soaking time can improve the product yield.

S3: Drying: the wafer after the secondary corrosion treatment is rinsed with water and dried, and then placed in a constant environment to dry.

Among them, the preferred temperature of the constant environment is 20°C, the humidity is 15%, and the drying time is 20-24h. The mobile ions brought by the residual water vapor during the corrosion process may cause a small amount of leakage instability in the product. Therefore, drying in a standard constant environment can remove water vapor to ensure the consistency of product leakage and improve product yield.

Example 3:

In Example 2, the pickling flower basket used in the primary corrosion and secondary corrosion steps is shown in Figure 2. The pickling flower basket is made of Teflon, including mask 1 and H surface 2. A plurality of through holes 3 are spaced apart on the surface 1, and the inner diameters of the through holes 3 gradually decrease from inside to outside.

Teflon flower baskets are often used in cleaning and corrosion treatment. In order to prevent the particles from falling on the surface of the product and avoid the deformation of the Teflon flower basket during the pickling process, the structure of the Teflon flower basket includes a mask. However, due to the blocking of the mask, the acid fluidity is poor, resulting in poor corrosion effect on the side close to the mask. After metal corrosion, the corrosion effect of the wafers in the flower basket is different, and after the product is processed, it is found that some wafers have a large leakage problem. , leading to low yield.

As shown in Table 1 and Table 2 below, chip numbers 1-5 and 26-30 are wafers close to the mask. Optimizing the pickling flower basket by opening a bell-shaped through hole in the mask can effectively improve the difference in the amount of side corrosion between the metal corrosion sheets, achieve the effect of balancing the corrosion amount in the flower basket, ensure the consistency of product leakage, and reduce the Rework rates for metal corrosion.

Table 1. Metal corrosion effect table before optimization of pickling flower basket

Table 2. Metal corrosion effect table after optimization of pickling flower basket

The above-mentioned technical solutions in the embodiments of the present application have at least the following technical effects or advantages:

1. Carry out secondary corrosion on the basis of conventional corrosion, and effectively solve the problem of residual metal particles on the surface of the product after corrosion through the metal particle corrosion solution, so as to ensure that the product will not have sudden leakage caused by metal particles;

2. Add a drying step after the secondary corrosion to remove the water vapor brought by the product due to corrosion and flushing to ensure the consistency of product leakage;

3. By opening bell-shaped through holes in the mask to optimize the pickling flower basket, it can effectively improve the difference in the amount of side corrosion between the metal corrosion sheets, achieve the effect of balancing the amount of corrosion in the flower basket, and ensure the consistency of product leakage. Reduced rework rates for metal corrosion.

Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and those skilled in the art can make the above-mentioned The embodiments are subject to changes, modifications, substitutions and variations.

Claims (8)

1. The metal particle corrosive liquid for the fast recovery diode is characterized by comprising the following components in percentage by volume of 1:0.7-0.8:0.2-0.3:0.2-0.3:0.1-0.15 of water, hydrogen peroxide, ammonia water, glacial acetic acid and an ethylene diamine tetraacetic acid mixed solution, wherein the mass ratio of the water to the ethylene diamine tetraacetic acid in the ethylene diamine tetraacetic acid mixed solution is 40-66:1.

2. the metal particle etching solution of claim 1, wherein: the hydrogen peroxide-based water-soluble paint also comprises a sodium hydroxide solution, wherein the water, hydrogen peroxide, ammonia water, glacial acetic acid, an ethylene diamine tetraacetic acid mixed solution and the sodium hydroxide solution are mixed according to a volume ratio of 1:0.7-0.8:0.2-0.3:0.2-0.3:0.1-0.15:0.1 to 0.15, wherein the mass percentage concentration of the sodium hydroxide in the sodium hydroxide solution is 1.5 to 2.5 percent.

3. The metal particle etching solution of claim 2, wherein: the water, hydrogen peroxide, ammonia water, glacial acetic acid, ethylene diamine tetraacetic acid mixed solution and sodium hydroxide solution are mixed according to the corresponding volume ratio of 1:0.75:0.25:0.25:0.125:0.125, wherein the weight ratio of water to the ethylenediamine tetraacetic acid in the ethylenediamine tetraacetic acid mixed solution is 50:1, in the sodium hydroxide solution, the mass percentage concentration of the sodium hydroxide is 2%.

4. The metal particle etching solution of claim 2, wherein: the preparation method of the metal particle corrosive liquid comprises the following steps:

mixing water and ethylene diamine tetraacetic acid powder according to the proportion to prepare ethylene diamine tetraacetic acid mixed solution, and mixing water and sodium hydroxide powder to prepare sodium hydroxide solution;

standing the ethylenediamine tetraacetic acid mixed solution and the sodium hydroxide solution for more than 1 h;

and mixing the water, hydrogen peroxide, ammonia water, glacial acetic acid and ethylenediamine tetraacetic acid mixed solution according to the proportion, and then adding a sodium hydroxide solution to mix to prepare the metal particle corrosive liquid.

5. A metal corrosion method of a fast recovery diode is characterized by sequentially comprising the following steps:

placing the photoetched wafer in an acid-washing basket, and performing primary metal corrosion treatment in a conventional manner;

soaking the wafer subjected to the primary metal corrosion treatment in the metal particle corrosion solution according to any one of claims 1 to 3, wherein the temperature of the metal particle corrosion solution is 18 to 22 ℃, the soaking time is 50 to 70s, and the pickling basket is shaken continuously during the soaking period to finish secondary corrosion;

and (4) flushing the wafer subjected to the secondary corrosion treatment, drying by spin-drying, and drying in a constant environment.

6. The metal etching method according to claim 5, wherein: and during secondary corrosion, the temperature of the metal particle corrosive liquid is 18 ℃, and the soaking time is 60s.

7. The metal etching method according to claim 6, wherein: the constant environment temperature is 20 ℃, the humidity is 15%, and the drying time is 20-24h.

8. The metal etching method according to claim 5, wherein: the pickling basket of flowers material is teflon, the pickling basket of flowers includes matte and H face, the pickling basket of flowers spaced apart on the matte is equipped with a plurality of through-holes, the through-hole internal diameter reduces from inside to outside gradually.

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