KR100853797B1 - Method and apparatus for manufacturing slurry in cmp process - Google Patents

Abstract

A method for fabricating slurry for a CMP process is provided to avoid malfunction of a storage tank, a filter and a transfer pump and excessive preventive maintenance by preventing large slurry particles from being left in the storage tank by a transfer pipe that is fabricated in a manner that ground slurry can be scattered and diluted during a transfer process. Slurry including deionized water and a polishing agent is fabricated and mixed. The mixed slurry is ground. The ground slurry is transferred to a storage tank part(210) wherein deionized water is added to dilute the ground slurry so that the slurry has a predetermined content of a polishing agent. Additive including a pH(hydrogen ion concentration) adjust agent and a polishing acceleration agent is mixed with the slurry diluted and transferred to the storage tank part. The additive-mixed slurry is filtered to obtain slurry having a desired size or less. The filtered slurry can be stored in a secondary storage tank part(216), and the slurry stored in the secondary storage tank part can be filtered again to obtain slurry having a predetermined size or less.

Description

Slurry production method and apparatus for chemical mechanical polishing process {METHOD AND APPARATUS FOR MANUFACTURING SLURRY IN CMP PROCESS}

1 is a view showing a slurry production apparatus for a general oxide film chemical mechanical polishing process.

2 is a view showing a slurry production apparatus for an oxide film chemical mechanical polishing process according to an embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

102, 202: mixer 104, 204: impeller

106,206: grinder 108,208: first pump part

110, 210: primary storage tank section 112, 212: second pump section

114, 214: primary filter section 116, 216: secondary storage tank section

118, 218: third pump section 120, 220: secondary filter section

     222: transfer pipe 224: deionized water addition unit

The present invention relates to a method and a manufacturing apparatus for a slurry (polishing liquid; slurry) of the chemical mechanical polishing (hereinafter referred to as 'CMP') process, and more particularly, dispersion and dilution during transportation after slurry grinding. A manufacturing method and apparatus for preventing malfunction and excessive maintenance of the storage tank, the filter, and the transfer pump by preventing large particles of slurry from remaining in the storage tank by using a transfer pipe manufactured to enable this possibility will be.

The CMP method was developed in the late 1980s by IBM in the US as a new polishing process that combines mechanical removal and chemical removal into a single processing method. In the conventional mechanical polishing method, a modified layer is formed. It is a defect on a semiconductor chip, and chemical polishing does not produce a deteriorated layer, but a planarized shape, that is, shape precision, cannot be obtained, and only a smooth surface can be obtained. Polishing the object by combining the advantages of these two processes is the basic concept of CMP.

The wafer is polished by a pad (a polishing cloth having a mechanical polishing element) and a slurry, and the polishing table on which the pad is attached performs a simple rotational movement, and the head part simultaneously performs the rotational movement and the oscillation movement. Pressurize at a constant pressure.

The wafer is mounted on the head part by surface tension or vacuum, and the surface of the head and the pad are brought into contact with each other by the self-load of the head part and the pressing force applied, and the slurry which is the processing liquid between the minute gaps (pores of the pad) between the contact surfaces. The flow is mechanically removed by the abrasive particles in the slurry and the surface protrusions of the pad, and chemically by the chemical components in the slurry.

In the CMP process, contact is made from the top of the device protrusion by the pressing force between the pad and the wafer, and the pressure is concentrated on this part to have a relatively high surface removal rate, and as the processing progresses, the recess is reduced and uniformly spread over the entire area. Removed.

The most important part of the chemistry of CMP is the role of abrasives. Despite the low content of abrasives, which is directly related to semiconductor production, the technique of increasing the polishing rate is a reality only possible with chemicals. Silica is widely used for semiconductor abrasives around the world, and mainly divided into fumed silica and colloidal silica.

1 is a view for explaining a slurry manufacturing method for CMP and a slurry manufacturing apparatus using the same according to a general technique.

1 is a view showing a slurry production apparatus for a general oxide film CMP, a mixer 102, an impeller 104, a mill 106, a first pump unit 108, a primary storage tank unit 110, It consists of the 2nd pump part 112, the primary filter part 114, the secondary storage tank part 116, the 3rd pump part 118, and the 2nd filter part 120. FIG.

Slurry for general oxide film CMP is first made of a high concentration slurry containing de-ionized water (DIW) and the abrasive silica (SiO2) in the mixer 102, and is mixed, the rotation of the impeller 104 Is prevented from rocking and adhering.

Subsequently, the grinder 106 connected to the connecting tube located at the bottom of the mixer 102 grinds a high concentration of silica slurry. Here, grinding includes not only the granularity of the fused silica but also the dispersion of the ground and granulated silica particles in an aqueous solvent.

Subsequently, the pulverized and granular slurry is transferred to the primary storage tank unit 110 through a connecting pipe, and the transfer is smoothed with the help of the first pump unit 108.

The slurry transferred to the primary storage tank unit 110 is diluted to a desired concentration, and a pH adjusting agent, a polishing accelerator, and the like are added.

Subsequently, the slurry to which the pH adjuster, the polishing promoter, and the like are added and mixed is transferred to the secondary storage tank unit 116 through a connection pipe attached to the bottom of the primary storage tank unit 110. With the help of 112, it passes through the primary filter 114 in the middle of the transfer. The primary filter unit 114 serves to filter out the coarse slurry particles agglomerated.

Subsequently, the slurry transferred to the secondary storage tank part 116 is transferred to the secondary filter part 120 with the help of the third pump part 118 to filter out the coarse slurry particles once more, and the secondary filter part. In step 120, the filtering process is performed.

The slurry thus prepared may be stored in another storage tank or sprayed directly into the CMP apparatus, although not shown.

However, the mixed and dispersed high concentration slurry transferred to the primary storage tank unit 110 is easily aggregated in the primary storage tank unit 110 to exist in a large mass, and is subsequently diluted and chemically added. It is not redistributed even during

If large chunks of slurry remain, this will shorten the life of the filter in the filtering step and cause a malfunction of the pump for transfer, which will affect the quality of the slurry.

Therefore, an object of the present invention is a slurry manufacturing method and apparatus of a chemical mechanical polishing process, to make a slurry of a certain concentration, mixed in a mixer, to pulverize the mixed slurry and to transfer the crushed slurry to the storage tank, the deionized water during the transfer It is to provide a manufacturing method and apparatus that can minimize the coarse slurry particles generated in the storage tank by diluting the ground slurry to a predetermined concentration by adding a.

In order to achieve the above object, one feature of the slurry manufacturing method of the chemical mechanical polishing process according to the present invention comprises the steps of making and mixing a slurry comprising deionized water and the abrasive; Pulverizing the mixed slurry; Transferring the pulverized slurry to a storage tank, and diluting the pulverized slurry to have a predetermined abrasive content by adding deionized water during transfer; Mixing an additive including a pH adjusting agent and an abrasive promoter to the diluted and transferred slurry to a storage tank part; And filtering the slurry mixed with the additive to obtain a slurry having particles having a desired size or less. It is made to include.

In order to achieve the above object, one feature of the slurry production apparatus of the chemical mechanical polishing process according to the present invention, a mixer for making and mixing a slurry comprising deionized water and the abrasive; A grinder connected to the mixer to grind the mixed slurry from the mixer; A transfer pipe for transferring the pulverized slurry to a storage tank part; A deionized water addition unit connected to a portion of a transfer path of the transfer pipe and diluting the slurry being pulverized and transferred to a storage tank to have a predetermined abrasive content by adding deionized water; A storage tank unit connected to the grinder through the transfer pipe and mixing and storing an additive including a pH adjusting agent and an abrasive promoter in a slurry in which deionized water is added during the transfer to dilute the content of the abrasive to have a predetermined value; And a filter unit connected to the storage tank unit to filter the slurry mixed with the additive to obtain a slurry having particles having a desired size or less. It is made to include.

Other objects, features and advantages of the invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

Hereinafter, with reference to the accompanying drawings illustrating the configuration and operation of the embodiment of the present invention, the configuration and operation of the present invention shown in the drawings and described by it will be described as at least one embodiment, By the technical spirit of the present invention described above and its core configuration and operation is not limited.

2 is a view for explaining a slurry manufacturing method for CMP and a slurry manufacturing apparatus using the same according to an embodiment of the present invention.

2 is a view showing a slurry manufacturing apparatus for oxide film CMP of the present invention, a mixer 202, an impeller 204, a grinder 206, a first pump portion 208, a primary storage tank portion 210, Second pump portion 212, primary filter portion 214, secondary storage tank portion 216, third pump portion 218, secondary filter portion 220, transfer pipe 222, and deionized water The addition part 224 is comprised.

2, first, deionized water and silica (SiO 2) are mixed in the mixer 202 to form a slurry having a predetermined concentration. At this time, the slurry is made to a high concentration and is mixed once, it is prevented from being rocked and adhered by the rotation operation of the impeller 204.

Here, the higher the concentration of the slurry, the smaller the average particle size of the silica slurry mixed in the mixer 202 (320 nm or less), the particle size distribution follows the normal distribution, and then the mill 206 of the crushed silica slurry The average particle size is small (160 nm or less) and can be made even.

Here, the content of the silica abrasive may be 28% by weight to 35% by weight, and in the present invention, the concentration of the silica abrasive is 28% by weight.

Subsequently, the grinder 206 connected to the connecting tube located at the bottom of the mixer 202 grinds a high concentration of silica slurry. Here, grinding includes not only the granularity of the fused silica but also the dispersion of the ground and granulated silica particles in an aqueous solvent.

Subsequently, the pulverized and granular slurry is transferred to the primary storage tank unit 210 through the transfer pipe 222, and the transfer is smoothed with the help of the first pump unit 208. At this time, the present invention is connected to a portion of the transfer path of the transfer pipe 222, deionized water addition unit for diluting to a predetermined concentration by adding deionized water to the slurry being crushed and transferred to the primary storage tank 210 224.

According to an embodiment of the present invention, the deionized water adding unit 224 is diluted by adding deionized water so as to be interlocked with the moving speed of the slurry being crushed and transferred to the primary storage tank 210.

In addition, according to the present invention, the deionized water adding unit 224 may be diluted to have a concentration of 5 wt% to 13 wt% of the abrasive in the slurry being transferred through the transfer pipe 222. Here, 5 wt% to 13 wt%, which is the concentration of the abrasive in the slurry, is the abrasive concentration of the desired slurry for CMP.

Here, the deionized water adding unit 224 is connected to a portion of the transfer pipe 222 through another connecting pipe, by mixing the deionized water by supplying the deionized water to the slurry being crushed and transferred to the primary storage tank 210 The silica abrasive concentration of the slurry is diluted.

This is to pre-dilute the slurry before it is stored in the primary storage tank 210, so that time is saved than when diluted after storage.

A slurry is a solution obtained by dispersing and mixing a solution such as an acid or a base in ultrapure water (DIW), and has a high cohesive force, and after a certain time, the aggregate accumulates on the bottom of the slurry storage tank. If the slurry aggregates are left untreated, clogging the pump or the supply line may damage the wafer during the chemical mechanical polishing process, and further stop the operation to correct the slurry tank. Pressure check and calibration, pad replacement of chemical mechanical polishing equipment, such as a large amount of time is a problem.

Therefore, unlike the conventional method for producing a slurry, the present invention can save time to dilute after storage in the storage tank, so that the thick slurry particles generated in the storage tank can be minimized over time.

Subsequently, the deionized water is supplied from the deionized water adding unit 224 during the transfer, and the diluted silica slurry is stored in the primary storage tank 210 connected to one end of the transfer pipe 222.

In the primary storage tank 210, an additive including a pH regulator and an abrasive promoter is mixed with the transferred slurry. In the present invention, when the additive including the pH adjusting agent and the polishing accelerator is mixed, the mixing is performed for about 30 minutes using a stirrer.

Subsequently, the slurry to which the pH adjusting agent, the polishing promoter, and the like are added and mixed is transferred to the secondary storage tank unit 216 through a connection pipe attached to the bottom of the primary storage tank unit 210. With the help of 212, it passes through the primary filter unit 214 in the middle of the transfer. The primary filter part 214 filters out the coarse slurry particles.

Subsequently, the slurry transferred to the secondary storage tank unit 216 is transferred to the secondary filter unit 220 with the help of the third pump unit 218 to filter out the slurry particles thicker once more, and the secondary filter unit. In step 220, the filtering process is performed.

The slurry thus prepared may be stored in another storage tank or sprayed directly into the CMP apparatus, although not shown.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

As described above, the slurry manufacturing method and apparatus of the chemical mechanical polishing process according to the present invention are made so that large particles of the slurry are not left in the storage tank by using a transfer pipe manufactured to enable dispersion and dilution during transportation after grinding the slurry. As a result, malfunctions and excessive maintenance of the storage tank, the filter, and the transfer pump can be prevented.

Claims (10)

Making and mixing a slurry comprising deionized water and an abrasive; Pulverizing the mixed slurry; Transferring the pulverized slurry to a storage tank, and diluting the pulverized slurry to have a predetermined abrasive content by adding deionized water during transfer; Mixing an additive including a pH adjusting agent and an abrasive promoter to the diluted and transferred slurry to a storage tank part; And Filtering the slurry mixed with the additive to obtain a slurry having particles of a desired size or less; Slurry manufacturing method of a chemical mechanical polishing process comprising a. The method of claim 1, After the filtering step, further comprising the step of storing the filtered slurry in the secondary storage tank portion and secondary filtering the slurry stored in the secondary storage tank portion to obtain a slurry having particles of a desired size or less; Slurry manufacturing method of a chemical mechanical polishing process, characterized in that. The method of claim 1, The crushed slurry is transferred to a storage tank, but when deionized water is added during the transfer, the deionized water is added to the deionized water so as to be interlocked with the moving speed of the pulverized slurry being transferred to the storage tank. Slurry Preparation Method. The method of claim 1, The polishing agent is silica (SiO ₂ ), and the chemical mechanical polishing process is a slurry production method of a chemical mechanical polishing process, characterized in that the polishing of the oxide film. The method of claim 4, wherein When the slurry containing the deionized water and the abrasive is prepared and mixed, the content of the abrasive is 28% by weight to 35% by weight, and the slurry diluted so that deionized water is added to the storage tank part to have a predetermined abrasive content is an abrasive. Slurry production method of a chemical mechanical polishing process, characterized in that the content of 5% by weight to 13% by weight. A mixer for making and mixing a slurry comprising deionized water and an abrasive; A grinder connected to the mixer to grind the mixed slurry from the mixer; A transfer pipe for transferring the pulverized slurry to a storage tank part; A deionized water addition unit connected to a portion of a transfer path of the transfer pipe and diluting the slurry being pulverized and transferred to a storage tank to have a predetermined abrasive content by adding deionized water; A storage tank unit connected to the grinder through the transfer pipe and mixing and storing an additive including a pH adjusting agent and an abrasive promoter in a slurry in which deionized water is added during the transfer to dilute the content of the abrasive to have a predetermined value; And A filter part connected to the storage tank part to filter the slurry mixed with the additive to obtain a slurry having particles having a desired size or less; Slurry production apparatus of a chemical mechanical polishing process comprising a. The method of claim 6, A slurry having particles of a desired size or less by secondary filtering the slurry stored in the secondary storage tank and connected to the secondary storage tank and the secondary storage tank, which is connected to the filter unit and stores the filtered slurry. Slurry manufacturing apparatus of a chemical mechanical polishing process, characterized in that further comprises a secondary filter to obtain. The method of claim 6, The deionized water adding unit adds the deionized water so as to be linked with the moving speed of the slurry being crushed and transferred to the storage tank unit. The method of claim 6, The abrasive is silica (SiO ₂ ), the use of the chemical mechanical polishing process slurry production apparatus of a chemical mechanical polishing process, characterized in that the polishing of the oxide film. The method of claim 9, The slurry containing the deionized water and the abrasive produced in the mixer has an abrasive content of 28% by weight to 35% by weight, and the deionized water addition part adds deionized water so that the content of the abrasive is 5% by weight to 13% by weight. Slurry manufacturing apparatus of a chemical mechanical polishing process characterized in that the dilution of the slurry being transferred through the transfer pipe.

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