WO2015064809A1

WO2015064809A1 - Method for manufacturing recycling au target for semiconductor

Info

Publication number: WO2015064809A1
Application number: PCT/KR2013/009984
Authority: WO
Inventors: 강동한; 홍길수; 양승호; 윤원규
Original assignee: 희성금속 주식회사
Priority date: 2013-10-28
Filing date: 2013-11-06
Publication date: 2015-05-07
Also published as: KR20150048538A

Abstract

The present invention relates to a method for manufacturing an Au target used for a semiconductor redistributed layer (RDL) or a bump and, more particularly, to a novel method for recycling a waste target using plasma spray coating. In the present invention, a waste target is recycled by spraying high-purity powder thereto. Therefore, it is possible not only to provide a target having high-density, high-purity fine crystal grains, but also to effectively reduce manufacturing time and costs.

Description

【Specification】

[Name of invention]

Manufacturing Method of Recycling Au Target for Semiconductor 【Technical Field】

The present invention relates to a method for manufacturing a target by spraying a high-purity powder on Au waste target used 20% or more as a method for recycling the Au waste target, and to clean the surface through the waste target pre-treatment process and fine grain of high purity Eggplant relates to a new method of making a recycle target.

Background Art

Au targets are widely used for RDL (Redistributed Layer) or Bump.

The process for RDL is a process of changing a semiconductor chip input / output terminal to a package easily. NAND flash has a problem in that the pad position is located in the center, so that when the stacking is complicated, the package becomes complicated and the wire length becomes longer, thereby decreasing the speed. In order to solve this problem, an RDL process is used to facilitate padding by placing a pad position at an edge. Such RDL is advantageous in terms of semiconductor packaging process, but the metal is torn off in the bonding layer, and more problems occur when the metal thickness is thin. To compensate for this, it is necessary to uniformly form a gold target through sputtering.

Bumping is also used in wafer packaging and assembly during semiconductor packaging and assembly. It is a post-semiconductor process that delivers electrical signals by forming bump-shaped metals without connecting the electrical contacts of the circuit with existing bonding wires. In recent years, as semiconductor chips have become high-performance, high-integration, and light-weight and short-sized, bumping technology has emerged as an alternative, with technical limitations appearing in the existing wire method.

As the semiconductor process rapidly develops as described above, the Au target used is also required to improve performance. In order to control uniform thickness and surface impurities in the semiconductor film forming process, the crystal grains of the Au target are fine and a high purity target is required. In addition, as usage increases, innovative manufacturing methods for recycling waste targets are required to reduce costs.

[Detailed Description of the Invention]

[Technical problem]

The present invention has been made to solve the above-described problems, after the surface cleansing using Au waste target, after producing a fine and high purity Au powder prepared by coating a high purity powder prepared on the surface of the Au waste target When the waste target is recycled, it is conceived that a recycling target having fine grains of high purity can be newly manufactured.

Accordingly, the present invention removes impurities contaminated on the surface of the waste target, manufactures a highly purified powder using plasma, and then uses a plasma spray coating equipment to develop a new Au recycling target having fine grains of high purity. It is an object to provide a manufacturing method. Technical Solution

The present invention, in the production of a high density and high purity target by recycling the waste target, (a) De-bonding the waste target Au; (b) removing impurities attached to the waste target; (c) preparing Au powder to be coated on the waste target; (d) coating the waste target surface using the prepared Au powder-ol plasma spray coating equipment; And (e) bonding and processing the coated Au target.

According to a preferred embodiment of the present invention, the step (b) is carried out one or more times to remove the impurities attached to the waste target using nitric acid or aqua regia, the purity of the target from which impurities are removed in the step (b) Is preferably at least 99.995 wt%. In addition, according to another preferred embodiment of the present invention, the Au powder of step (c) is prepared by a plasma method, the purity is preferably 99.995 wt% or more.

In addition, in the present invention, the step (d) is equipped with the Au waste target from which impurities are removed to the plasma spray coating equipment, and after loading the Au powder prepared in the step (c), Au powder by plasma gas Melting may be to deposit on the waste target.

Here, the relative density of the recycled Au target deposited using the plasma spray coating equipment in step (d) is preferably 99.0% or more, and purity is 99.995 wt% or more.

In addition, the recycled Au target prepared in the present invention is a semiconductor RDL, Brnnp layer or It can be used for both of them.

In addition, according to another preferred embodiment of the present invention, the Au waste target and Au powder may be used by replacing each of the waste target and powder having a component selected from the group consisting of Ag, Pt, Ta, Ru, and Ir.

Advantageous Effects

As described above, since the present invention manufactures a recycling target by spraying powder on Au waste target used for RDL (Redistributed Layer) or Bump, the target particle size, process time and manufacturing cost are drastically reduced to increase economic efficiency. Can be.

In addition, the Au target recycling method used in the present invention can be usefully used in the process of recycling targets such as Ag, Pt, Ta, Ru, Ir used in the semiconductor and HDD process.

In addition, since the Au target manufactured in the present invention is recycled using a waste target without a recovery process, the manufacturing period can be shortened by 30% or more.

[Brief Description of Drawings]

1 is a work flow chart for manufacturing a high purity Au target using the waste target of the present invention.

2 is a waste target photograph before bonding used in the present invention.

Figure 3 is a photograph of the Au target manufactured using the recycling method according to the present invention. [Form for implementation of invention]

Hereinafter, the present invention will be described in detail.

Since the wet method, which is a method of manufacturing an Au target, is recovered by a dissolution method using aqua regia, the process takes a long time. On the other hand, as the semiconductor process develops, the Au target is required to improve performance. In particular, the grains are fine and the situation is required to manufacture a high purity Au target. Therefore, as the amount of Au is increased, economic deterioration is inevitably caused.

Accordingly, in the present invention, a high purity target is manufactured by recycling the Au waste target, and a high purity powder is prepared in a short time by using a dry plasma (plasma) for powder production, and the high purity powder prepared is plasma spray coated (Plasma). Spray coating) is sprayed on the surface of the waste target to be recycled using the manufacturing method, characterized in that the manufacture of recycled high purity target.

Plasma Spray Coating is a method in which plasma gas is injected into the nozzle between the anodes and is formed on the surface of the coating. The plasma gas, which is ionized between the cathode and the anode in the plasma gun, is released into the atmosphere, thereby providing high energy. When the powder is supplied to such a hot flame, the powder melts in a short time and forms a coating layer having uniform and fine grains while impinging on the substrate. Since the plasma spray coating method coats the molten powder, the coating (deposition) speed is very fast, and the formed coating layer maintains the powder composition almost intact, making it easy to control the composition of the coating layer, and in addition to the existing metals or organic compounds, ceramic materials, etc. Various composite materials can be easily deposited. In the present invention, since the high-purity powder is sprayed and recycled to the waste target through the above-described plasma spray coating method, it is possible to prepare an Au target having fine grains of high density and high purity equivalent to that of a conventional target in a short time, as well as manufacturing time. And cost effective.

In addition, in the present invention, since the waste target is recycled, the economic efficiency can be significantly increased through cost reduction.

Hereinafter, a method of manufacturing a recycle Au target for a semiconductor according to the present invention will be described. However, it is not limited only by the following manufacturing method, and the steps of each process may be modified or optionally commonly used as necessary.

The manufacturing method of the recycled Au target for semiconductors which concerns on this invention is high purity to Au waste target.

Au powder may be prepared by thermal spraying through a plasma spray coating method.

For one preferred embodiment of the manufacturing method, (a) debonding the waste target Au;

(b) removing impurities attached to the waste target; (c) preparing Au powder to be coated on the waste target; (d) coating the prepared Au powder on the waste target surface using a plasma spray coating equipment; And (e) bonding and processing using the coated Au target.

Hereinafter, the manufacturing method will be described by dividing each step as follows. First, (1) proceeds to debond the waste target (S10).

The waste target is not particularly limited as long as it is a previously used target.

20% or more of the targets can be used.

In addition, the waste target uses an Au target that is frequently used in a semiconductor process. However, the present invention is not limited to the above-described Au targets, and other waste targets used in semiconductor and HDD processes, for example, Ag, Pt, Ta, Ru, IT or waste targets having alloys thereof may also be used. Belongs to the category of.

Debonding is performed using the above-described waste target, and the debonding may be performed at a temperature of 200 ^° C. to 300 ^° C. At this time, before debonding, the waste target portion may be attached using a high temperature tape to prevent contamination of indium and impurities. After the high temperature tape is attached to the waste target, the temperature is raised, for example, the temperature may be increased to 200 to 300 ^° C at a temperature of 5 to 10 ° C. At this time, if the temperature is drastically raised to a temperature exceeding 10 ^° C, since deformation of the backing plate may occur, it is preferable to raise the temperature to 10 ^° C or less. In addition, when the temperature reaches 200 ~ 300 ^° C, it should be maintained for 30 ~ 60 minutes before debonding.

(2) remove impurities attached to the debonded waste target (S20).

In the second step, indium and surface contaminants attached to the waste target are removed using nitric acid or aqua regia.

For example, in order to remove indium and surface contaminants remaining on the waste target surface, the waste target is first introduced into nitric acid for 1 to 3 hours. Maintain a degree. Then, in order to increase the removal time and effect of the rhythm, it is taken out of nitric acid every 30 minutes and wiped the surface with a polishing cloth. At this time, when using a polishing cloth containing a polishing liquid, since the impurities are attached to the target surface is lowered purity, it is preferable to use a polishing cloth containing no polishing liquid.

In the present invention, in order to check whether impurities attached to the surface are removed during the holding process, the specimens are collected by time and subjected to ICP analysis. The purity of the waste target from which the impurities are removed is preferably adjusted to 99.995 wt% or more. At this time, if the analysis value is 99.995 wt% or more, the process proceeds to the next third step. If the analysis value is less than 99.995 wt%, the impurities removal process, for example, nitric acid treatment and polishing process, is repeated one or more times.

(3) The high purity powder to be coated on the waste target is prepared by the plasma method (S30). In the third step, as a high purity powder to be deposited on the cleaned waste target, a powder having the same components as the waste target is prepared.

In the present invention, Au high purity powder is preferably prepared by a plasma (plasma) method, it can be prepared by other conventional methods known in the art. In the case of using the plasma method, the waste target may be cleaned or added, or a high purity bulk may be added as a raw material, and then residual impurities may be removed by using plasma, and then the plasma silver may be increased to obtain a highly purified powder. have.

According to a preferred example of this step, the powder is produced using a plasma apparatus. High purity bulk of 99.995 wt% or more inside the chamber of the plasma apparatus; Use granules or clean the lung target before cutting it. At this time, the input weight should not exceed 500 ~ 2000gr range. If the input weight is less than 500gr, there is a high risk that the plasma reacts with the crucible and is damaged. If the input weight is more than 2000gr, there is a possibility that the molten metal overflows the outside of the crucible and attaches to the chamber. The injected raw material is simply melted by forming a plasma at low power (less than 10 kW) and then removes impurities. At this time, the plasma power is adjusted low to vaporize the impurities of low melting point and removed to the outside by the vacuum apparatus. It is particularly effective for removing indium (In) used in the target manufacturing process.

After the impurities are removed, the power is elevated to produce a powder of high purity. In this case, the power used may increase the power in the range of 10 to 30 kw, and the plasma gas may be prepared by using argon, argon and nitrogen, argon and hydrogen mixed gas. The working vacuum during the powder production is carried out at 200 to 600 Torr. In this case, when the working vacuum degree is less than 200torr, the electrode life used is shortened, and impurities due to electrode damage are increased, and when the working vacuum degree exceeds 600torr, there is a problem that the powder manufacturing speed is drastically reduced.

A classification process is performed to ensure uniformity of the powder. At this time, the classification process can be carried out using a 200 mesh classifier, the powder exceeding 200 mesh is used during the spraying process, the powder below 200 mesh is put into the powder production.

As described above, the Au high purity powder prepared by the plasma method may have a purity of 99.995 wt% or more, and the crystal grains may be spherical powder having a range of 4 to 10 im. (4) The waste target from which impurities are removed is mounted on the plasma spray coating equipment and then deposited on the waste target using the prepared powder (S40).

In the fourth step, the high-purity powder obtained in the previous step is injected into the plasma spray equipment to spray the waste part of the waste target. At this time, the plasma spray coating method can change the density, porosity, etc. of the coating layer according to their characteristics according to the process conditions.

As a preferable example of the above step, the Au waste target from which impurities are removed is mounted on a plasma spray coating equipment, the high purity Au powder prepared in the previous step is charged, and the Au powder is melted by plasma gas to melt the waste target. It is to deposit on. First, the waste target from which impurities are removed is mounted on the Plasma Spray Coating Equipment. The prepared powder is charged with 500 ~ 1000gr into the feeder, the chamber is closed, and the vacuum is removed using a rotary pump up to 5.0 Χ ΐσ ² ton or less. When the aforementioned vacuum degree is reached, the working vacuum degree is maintained in the range of 200 to 600 torr using nitrogen gas. If the vibration is less than 200torr, the electrode is likely to be damaged, and if it exceeds 600 torr, the air outside the chamber is introduced and oxidized.

If the working vacuum is maintained in the range of 200 ~ 600torr, plasma gas is injected and spraying is performed. At this time, the plasma gas used may be a gas having a conventional composition known in the art, and for example, argon, nitrogen, argon + nitrogen, argon + hydrogen, nitrogen + hydrogen may be used. After generating the plasma, the rotational speed of the waste target is adjusted to a range of 2 to 10 RPM. If the rotational speed of the waste target is less than 2 RPM, the waste target is melted and the grain size is increased. It is fast and deposits unevenly.

After adjusting the rotational speed of the waste target as described above, the powder of the same component as the waste target is added, wherein the powder injection rate may be in the range of 10 ~ 50gr / min. If the input speed is less than 10gr / min takes a long time, if it exceeds 50gr / min waste target is not deposited and falls to the bottom of the chamber, the yield is lowered. In addition, the deposition time is about 10 to 120 minutes, and after the completion of the deposition is sufficiently angled more than 30 minutes, and then the chamber is opened to take out the target.

The recycled Au target prepared as described above preferably has a relative density of 99.0% or more, and a purity of 99.995 wt% or more.

(5) Process and bond the deposited target using a plasma spray coating equipment (S50).

In the above step, the carbon attached to the surface of the sintered body is removed by using a shelfol and then bonded.

Bonding is carried out using indium, in which the temperature can be carried out in the range of 200 ~ 300 ^° C. After bonding, the bonding rate is measured using ultrasonic flaw detection. The bonding rate measured should be at least 99.0%. When the bonding ratio is less than 99.0%, bonding is performed again after debonding.

After bonding, the lathe is processed to the final thickness. Beading process is performed on the backing plate surface of the processed target. The processed target is packaged after cleaning the semiconductor. In the present invention, the Au waste target and Au powder are mainly described, but other waste and waste targets of components selected from the group consisting of Ag, Pt, Ta, Ru, and Ir are used in semiconductor and HDD processes. It can be used in place of each powder. For example, when using an Ag waste target, the powder component to be deposited on the Ag waste target may be used as an Ag powder.

The present invention also provides a recycle Au target prepared by the above-described method.

The recycled Au target is preferably used for a semiconductor RDL, a bump layer, or both, and may be applied without limitation to other technical fields in which other _Au targets may be usefully applied.

The present invention is a waste target that is cleaned by removing the contaminated impurities on the surface; And the same components as the waste target and manufactured by using the plasma process, respectively, followed by melting the high-purity powder by using a plasma spray coating (Plasma Spray coating) equipment to spray the waste on the consumed portion of the target. Recycle target was prepared. As described above, the present invention can not only recycle the waste target but also exhibit the same physical properties as that of the target manufactured by other methods, that is, high purity and high density, and thus, economical efficiency can be secured by shortening the manufacturing time and cost.

Hereinafter, the present invention will be described in detail with reference to Examples, but the following Examples and Experimental Examples are merely illustrative of one embodiment of the present invention, and the scope of the present invention is not limited to the following Examples and Experimental Examples. EXAMPLE

The used 4 inch waste target 600gr was debonded. The target size, thickness and weight before consumption were 4 inch, 5 mm (t) and 800 gr, respectively. The waste target was maintained at 200 ^° C. for 60 minutes and then debonded. Indium remaining on the target surface after debonding was removed. A waste target from which indium was removed was put in a beaker containing nitric acid to remove residual indium and impurities. The removal time was about 2 hours, and surface impurities were removed using a polishing cloth every 30 minutes. Samples of the waste target from which impurities were removed were analyzed for impurities using ICP, and the purity was 99.999%.

The new powder to be prepared was prepared using a plasma equipment. Au waste target l, 000gr was charged into the crucible. After arranging the vacuum to 5.0 x l (r ² torr) by using a rotary pump, argon atmosphere was formed by argon gas injection. At this time, the working vacuum was maintained at 400 torr. Plasma was formed on the injected raw material and the high purity W electrode rod. Au powder was initially removed, and impurities remaining in the waste target were removed at 5 kw, and power consumption was increased by 20 kw to prepare a fine powder of high purity. Au powder 800gr was prepared using the powder, and the obtained powder was obtained by classifying a 200 mesh powder 600gr.For comparison, the powder was prepared by increasing the power to 30kw.The conditions of the manufacturing process are shown in Table 2 below. , Purity, average powder size and carbon content of the prepared Au powder is shown in Table 3.

Table 1

Step 1 Step 2

(Low Power) (High Power)

Applied Plasma Output 5Kw 20Kw

Composition for plasma Ar Ar, Ar + N ₂ , Ar + He

Gas Gas Flow Rate 20L / min 20L / min Quenching Gas Composition (Flow) Ar + N ₂ (150L / min) Ar + N ₂ (150L / min)

Table 2

Table 3

From the results of Table 3, in the case of Au powder prepared by plasma to obtain a spherical powder of 4 ~ 10 m level. The purity of the powder also secured the results at 99.995-99.999 wt%. The carbon content tended to increase rapidly as the power increased. When the power increased, the carbon content of the surface of the crucible reacted with the manufactured powder, and the carbon content tended to increase. However, if the carbon content of the powder is increased, it may affect the formation of nodule during film formation using the final target. Less than 30kw The powder should be prepared under the conditions. Purity 99.999wt%, average powder size 10 / m, carbon content 40ppm at 20kw powder production conditions.

Reuse targets were prepared using Au powder and Au waste targets prepared under 20 kw conditions. First, high-purity waste targets (4inch, 5t, 600gr) with debonding and impurities removed were mounted on a plasma spray coating equipment. After loading 200 gr of Au powder below 200 mesh into the feeder, vacuum was extracted up to 5.0 X l () ^"2 torr. The working vacuum was maintained at 500 torr using N ₂ Gas, and the rotational speeds of the mounted targets were respectively 2, 5, 10 RPM, the rotation speed was 15 RPM for comparison The manufacturing process is shown in Table 4. Plasma Gas used is Ar, N ₂ , Ar + N ₂ , Ar + He The feed rate was 20 L / min Feeder speed was 20 gr / min and the results are shown in Table 5 below.

From the results in Table 5 below, in Example 3 having a working vacuum of 500 torr, a rotational speed of 10 RPM, a plasma gas of 20 L / min, and a feeder amount of 20 gr / min, the highest deposition property and a high density target having a relative density of 99.5% or more were obtained. In the case of the comparative example, the rotation speed was high, and the thickness was unevenly deposited on the target.

Bonding was performed after removing the carbonol from the surface by using the secured high density target of Example 3. Bonding was performed at 200 ^° C. using indium, and a bonding rate of 99.5% was secured. The bonded target was machined to 4 inch × 5t using a lathe. After the bead treatment was performed on the backing, semiconductor grade cleaning and vacuum packaging were performed.

Table 4 Rotational Speed (RPM) 2 5 10 15 For Plasma

Composition Ar, N ₂ , Ar + N ₂ , Ar + He Gas

For plasma

Flow rate (L / min) 20 gas

Working Vacuum Degree (Torr) 500

Feeder amount (gr / min) 20

[Table 5]

Claims

【Scope of Claim】

【Claim 1】

In manufacturing high-density and high-purity targets by recycling waste targets,

(a) debonding the Au lung target;

(b) removing impurities attached to the lung target;

(c) preparing Au powder to be coated on the lung target;

(d) coating the prepared Au powder on the surface of the waste target using plasma spray coating equipment; and

(e) bonding and processing using the coated Au target;

A method for manufacturing a recycled Au target comprising:

【Claim 2】

The method of manufacturing a recycled Au target according to claim 1, wherein step (b) is performed at least once to remove impurities attached to the waste target using nitric acid or aqua regia.

【Claim 3】

The method of manufacturing a recycled Au target according to claim 1, wherein the purity of the target from which impurities are removed in step (b) is 99.995 wt% or more.

【Claim 4】

The method of claim 1, wherein the Au powder in step (c) is manufactured by a plasma method and has a purity of 99.99 ⁵ wt% or more.

【Claim 5】 The method of claim 1, wherein the Au powder prepared in step (c) is a spherical powder with a crystal grain size in the range of 4 to 10.

【Claim 6】

The method of claim 1, wherein in step (d), the Au waste target from which impurities have been removed is mounted on a plasma spray coating equipment, the Au powder prepared in step (c) is charged, and the Au powder is sprayed by plasma gas. A method of manufacturing a recycled Au target, characterized in that melting and depositing on the waste target.

【Claim 7】

The method of claim 6, wherein the relative density of the recycled Au target deposited in step (d) is 99.0% or more.

【Claim 8】

The method of claim 6, wherein the purity of the recycled Au target deposited in step (d) is 99.995 wt% or more.

【Claim 9】

The method of claim 1, wherein the recycled Au target produced by the method is RDL for semiconductors,

A method of manufacturing a recycled Au target, characterized in that it is used in the bump layer or both.

[Claim 10]

The recycled Au of claim 1, wherein the Au waste target and Au powder can be replaced with a waste target and powder having components selected from the group consisting of Ag, Pt, Ta, Ru, and Ir, respectively. Target manufacturing method.