TWI900096B - Apparatus and method for treating polishing slurry - Google Patents

Abstract

The present invention discloses an apparatus and a method for treating polishing slurry, the apparatus comprising a filtration unit, a permeation unit, and a control unit. The apparatus further comprises a transmission pipeline connecting the filtration unit and the permeation unit. The control unit primarily comprises an electronic circuit and controls the filtration unit and the permeation unit. The filtration unit is used for removing a plurality of first particles having a particle size greater than a first dimension contained in the polishing slurry, and transmitting the filtered polishing slurry to the permeation unit. The permeation unit is used for removing at least a portion of a plurality of second particles having a particle size smaller than a second dimension contained in the polishing slurry, thereby obtaining the polishing slurry with homogenized particle size distribution.

Description

Grinding slurry processing device and processing method

The present invention relates to a grinding slurry used in the field of chemical mechanical grinding; in particular, to a grinding slurry processing device and processing method.

Chemical mechanical polishing (CMP) is widely used in wafer polishing. It primarily involves the use of a polishing pad and a polishing slurry. A grinding disc, equipped with the polishing pad, faces the wafer, contacting the surface of the wafer. As the pad and wafer move relative to each other, the polishing slurry is fed between them to complete the polishing process.

The polishing slurry is mainly composed of a stock solution with abrasive grains added in an appropriate proportion, wherein the stock solution is composed of a concentrated liquid mixed with a diluent composed of chemical components. During the polishing process, the abrasive grains remove the wafer to form a polishing effect. The particle size of the abrasive grains directly affects the amount of the wafer removed by the abrasive grains. Controlling the particle size range of each abrasive grain that constitutes the polishing slurry helps to control the surface flatness of the wafer after polishing. However, among the majority of the abrasive grains added to the stock solution, some have particle sizes that are too large or too small. If the particle size distribution span of each abrasive grain in the polishing slurry can be made more uniform, it will help to improve the quality of the polishing process.

The main purpose of the present invention is to provide a grinding slurry processing device and processing method.

To achieve the aforementioned objectives, the present invention adopts the following technical solutions:

A grinding slurry processing device includes a filter unit, a permeation unit, a transmission pipeline, and a control unit, wherein the transmission pipeline connects the filter unit and the permeation unit, and the control unit is mainly composed of an electronic circuit. The control unit is coupled to the filter unit and the permeation unit to control the filter unit and the permeation unit accordingly.

The filtering unit is used to filter the grinding slurry from an external grinding slurry source, remove a plurality of first particles with a particle size larger than a first size contained in the grinding slurry, and transmit the filtered grinding slurry to the permeation unit through the transmission pipeline;

The permeation unit includes a permeator, wherein a permeation membrane is provided inside the permeator, a first channel is located on one side of the permeation membrane, and a second channel is located on the other side of the permeation membrane. One end of the first channel is connected to a first pipeline, which is connected to the transmission pipeline. The other end of the first channel is connected to a second pipeline, which is used to connect to an external storage tank. One end of the second channel is connected to a third pipeline, which is used to connect to an external raw liquid supply source. The other end of the second channel is connected to a fourth pipeline, which is used to connect to an external storage tank.

Accordingly, the grinding slurry enters the second pipeline from the first pipeline through the first channel, and multiple second particles with a particle size smaller than the second size contained in the grinding slurry permeate through the permeable membrane and enter the second channel. The raw liquid supply source supplies raw liquid from the third pipeline through the second channel into the fourth pipeline, and leads each of the second particles entering the second channel into the receiving tank through the fourth pipeline.

A processing method, which is performed using the grinding slurry processing device as described above, comprises the following steps performed in sequence:

Introducing grinding slurry: guiding the grinding slurry from the grinding slurry source into the filtering unit;

Screening and filtering: the filtering unit screens and filters the grinding slurry to remove the first particles with a particle size larger than the first size contained in the grinding slurry;

Osmotic removal: The milled slurry that has passed the screening and filtration step is introduced into the osmotic unit to remove at least a portion of the second particles contained in the milled slurry, so that the milled slurry mainly contains third particles with a particle size between the first size and the second size, thereby obtaining the milled slurry with a homogenized particle size span.

The main effects and advantages of the present invention are that it can remove the first particles having a particle size larger than the first size from the grinding slurry and remove most or all of the second particles from the grinding slurry 90, so that the particle size distribution span of the abrasive particles in the grinding slurry tends to be homogenized, thereby improving the grinding process quality of the chemical mechanical grinding process performed using the grinding slurry. In addition, the present invention can be used to process the prepared grinding slurry and can also be used to process the grinding slurry containing chips recovered during the grinding process.

The drawings show preferred embodiments of the present invention, but these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention in patent applications.

As shown in Figures 1 to 3, the grinding slurry processing device of the present invention includes a filter unit 10, a permeation unit 20, a transmission pipeline 30 and a control unit 40, wherein the transmission pipeline 30 connects the filter unit 10 and the permeation unit 20, and the control unit 40 is mainly composed of an electronic circuit. The control unit 40 couples the filter unit 10 and the permeation unit 20 to control the filter unit 10 and the permeation unit 20 accordingly.

The filter unit 10 is used to filter grinding slurry 90 from an external grinding slurry source (not shown), remove a plurality of first particles (not shown) having a particle size larger than a first size contained in the grinding slurry 90, and transmit the filtered grinding slurry 90 to the permeation unit 20 via the transmission line 30. The filter unit 10 is a prior art that can be directly and unambiguously applied by those skilled in the art to which the present invention pertains, and is not necessarily related to the technical features of the present invention. The specific structure of the filter unit 10 will not be described in detail.

The permeation unit 20 includes a permeabilizer 21, wherein a permeabilizer 21 is provided with a permeable membrane 22 inside. A first channel 23 is located on one side of the permeable membrane 22, and a second channel 24 is located on the other side of the permeable membrane 22. In this example, the permeable membrane 22 has a tubular structure and annularly surrounds the radial periphery of the first channel 23, and the second channel 24 surrounds the radial exterior of the permeable membrane 22.

One end of the first channel 23 is connected to a first pipeline 25, which is connected to the transmission pipeline 30. The other end of the first channel 23 is connected to a second pipeline 26, which is used to connect to an external storage tank (not shown). One end of the second channel 24 is connected to a third pipeline 27, which is used to connect to an external raw liquid supply source (not shown). The other end of the second channel 24 is connected to a fourth pipeline 28, which is used to connect to an external storage tank (not shown).

The storage tank is a container for storing the polishing slurry 90 after being processed by the polishing slurry processing device of the present invention, so that the polishing slurry 90 can be subsequently used in chemical mechanical polishing. The stock liquid supply source is a container for storing the stock liquid 91. The stock liquid 91 is a liquid prepared by mixing a concentrated liquid and a diluent composed of chemical components. The stock liquid 91 does not contain any abrasive particles that can remove the wafer or substrate to form a polishing effect. The storage tank is A container is provided for containing a slurry formed by mixing the stock solution 91 and fine particles produced after treatment by the permeation unit 20. The particles may be abrasive particles. The specific configurations of the storage tank, the stock solution supply source, and the receiving tank are not particularly limited and are not necessarily related to the technical features of the present invention. Persons skilled in the art to which the present invention relates can directly use various existing containers as the storage tank, the stock solution supply source, and the receiving tank.

The polishing slurry 90 used in chemical mechanical polishing is mainly composed of the stock solution 91 with the abrasive particles added in an appropriate proportion. The particle size distribution curve of the abrasive particles is generally as shown in FIG6 , where the horizontal axis represents the particle size of the abrasive particles and the vertical axis represents the number of the abrasive particles.

As shown in FIG5 and FIG6, the processing method performed using the grinding slurry processing apparatus of the present invention includes the following steps performed in sequence:

Introducing grinding slurry: guiding the grinding slurry 90 from the grinding slurry source into the filtering unit 10.

Screening and filtering: The filtering unit 10 screens and filters the grinding slurry 90 to remove the first particles with a particle size larger than the first size contained in the grinding slurry 90.

Osmotic removal: The grinding slurry 90 that has passed the screening and filtration step is introduced into the osmotic unit 20 to remove a portion or all of the second particles 92 contained in the grinding slurry 90, so that the grinding slurry 90 mainly contains third particles 94 with a particle size between the first size and the second size, thereby obtaining the grinding slurry 90 with a homogenized particle size span.

The present invention does not limit the specific values of the first size and the second size. The specific values of the first size and the second size are pre-set as needed, and the filter unit 10 and the permeable membrane 22 with corresponding specifications are selected according to the set first size and the second size.

The abrasive slurry 90 enters the second pipe 26 through the first channel 23 from the first pipe 25. The plurality of second particles 92 having a particle size smaller than the second size contained in the abrasive slurry 90 permeate through the permeable membrane 22 and enter the second channel 24. The raw liquid supply source supplies the raw liquid 91 through the third pipe 27 through the second channel 24 and into the fourth pipe 28. The raw liquid 91 is then carried by the second particles 92 that have entered the second channel 24 through the fourth pipe 28 into the receiving tank.

When the polishing slurry processing apparatus of the present invention is used to perform the processing method described above, the polishing slurry 90 composed of the stock solution 91 and the abrasive particles in appropriate proportions is processed. The first particles 92, the second particles 92, and the third particles 94 are the abrasive particles of different particle sizes.

By performing the screening filtration step, the first particles having a particle size larger than the first size can be removed from the polishing slurry 90 by the filtration unit 10. By performing the penetration removal step, the most or all of the second particles 92 can be removed from the polishing slurry 90 by the penetration unit 20. As a result, the polishing slurry 90 is mainly composed of the stock solution 91 and the abrasive particles, and the particle size of each of the abrasive particles is mostly the third particles 94 between the first size and the second size. This makes the particle size distribution span of the abrasive particles in the polishing slurry 90 tend to be homogenized, thereby improving the polishing quality of the chemical mechanical polishing process performed using the polishing slurry 90.

As shown in FIG3 , the flow direction of the grinding slurry 90 in the first channel 23 is opposite to the flow direction of the stock solution 91 in the second channel 24. As shown in FIG4 , the flow direction of the grinding slurry 90 in the first channel 23 and the flow direction of the stock solution 91 in the second channel 24 may also be the same. FIG3 is merely an example and cannot be used as an explanation to limit the present invention.

The stock solution 91 carries the second particles 92 into the receiving tank through the second channel 24. The stock solution 91 and the second particles 92 are mixed to form another type of polishing slurry having abrasive particles with a different particle size distribution range. The polishing slurry is mainly composed of the stock solution 91 and abrasive particles with a particle size smaller than the second size. Accordingly, the present invention can recover the second particles 92 with a particle size smaller than the second size that are removed from the polishing slurry 90 during the permeation removal step, and enable it to be applied in the chemical mechanical polishing process as the other type of polishing slurry used in a more precise polishing process.

By using the filtering unit 10 to perform the screening step, the first particles removed from the slurry 90 can also be recovered and added to the new stock solution 91, so that it can be applied to the chemical mechanical polishing process as a slurry used in a relatively coarse polishing process.

During the chemical polishing process, the portion of the wafer removed by the abrasive grains is broken into fine particle-shaped chips, which are carried away from the wafer or substrate surface along with the flowing polishing slurry 90. The chips are broken during the polishing process. By executing the aforementioned processing method and selecting the value of the second size as needed, at least most of the chips can be removed from the polishing slurry 90, allowing the polishing slurry 90 to be recycled in the chemical polishing process. At this time, the first particles, the second particles 92, and the third particles 94 are used to represent the abrasive grains or chips of different particle sizes.

The processing method of the present invention can remove the chips from the grinding slurry 90. When the grinding slurry 90 is circulated, the chips can be reduced from being deposited in the pipe through which the grinding slurry 90 circulates. This reduces the probability of the chips accumulating and agglomerating, thereby helping to improve the quality and efficiency of the grinding process.

As shown in Figure 1 again, the first pipeline 25 is provided with a first pump 252 for pumping the grinding slurry 90 through the first channel 23 into the second pipeline 26. The third pipeline 27 is provided with a third pump 272 for pumping the raw liquid 91 through the second channel 24 into the fourth pipeline 28. The control unit 40 couples the first pump 252 and the third pump 272 to control the operation of the first pump 252 and the third pump 272 so that the pressure in the second pipeline 26 is greater than or equal to the pressure in the third pipeline 27.

During the osmotic removal step, the pressure of the polishing slurry 90 passing through the first channel 23 located on one side of the permeable membrane 22 is greater than the pressure of the second channel 24 located on the other side of the permeable membrane 22, thereby causing the second particles 92 to permeate through the permeable membrane 22 and enter the second channel 24. The second particles 92 that have entered the second channel 24 cannot reversely permeate through the permeable membrane 22 and enter the first channel 23.

The second pipeline 26 is provided with a second pump 262 for drawing the polishing slurry 90 through the first channel 23 and pumping the polishing slurry 90 containing a plurality of third particles 94 having a particle size between the first size and the second size to the storage tank. The fourth pipeline 28 is provided with a fourth pump 282 for drawing the stock solution 91 containing a plurality of second particles 92 through the second channel 24 and pumping the stock solution 91 containing a plurality of second particles 92 to the storage tank. The control unit 40 is coupled to control the second pump 262 and the fourth pump 282.

The first pipe 25 is provided with a first flow pressure sensor 254 located between the first pump 252 and the permeabilizer 21 for sensing the pressure of the grinding slurry 90 passing through the first pipe 25. The second pipe 26 is provided with a second flow pressure sensor 264 located between the second pump 262 and the permeabilizer 21 for sensing the pressure of the grinding slurry 90 passing through the second pipe. 26, the third pipeline 27 is provided with a third flow pressure sensor 274 located between the third pump 272 and the permeabilizer 21, for sensing the pressure of the raw liquid 91 passing through the third pipeline 27, the fourth pipeline 28 is provided with a fourth flow pressure sensor 284 located between the fourth pump 282 and the permeabilizer 21, for sensing the pressure of the raw liquid 91 passing through the third pipeline 27. The pressure of the four pipes 28, the first flow pressure sensor 254, the second flow pressure sensor 264, the third flow pressure sensor 274 and the fourth flow pressure sensor 284 are respectively coupled to the control unit 40, thereby, the control unit 40 can be based on the first flow pressure sensor 254, the second flow pressure sensor 264, the third flow pressure sensor The flow sensor 274 and the fourth flow pressure sensor 284 detect the flow and respectively control the operation of the first pump 252, the second pump 262, the third pump 272 and the fourth pump 282, so that the pressure of the polishing slurry 90 passing through the first channel 23 located on one side of the permeable membrane 22 is greater than the pressure of the second channel 24 located on the other side of the permeable membrane 22.

The second pipeline 26 is provided with a second flow meter 266 located between the second pump 262 and the second flow pressure sensor 264 for sensing the flow of the grinding slurry 90 passing through the second pipeline 26. The fourth pipeline 28 is provided with a fourth flow meter 286 located between the fourth pump 282 and the fourth flow pressure sensor 284 for sensing the flow of the raw liquid 91 passing through the fourth pipeline 28. The second flow meter 266 and the fourth flow meter 286 are respectively coupled to the control unit 40, so that the control unit 40 adjusts the flow of the grinding slurry 90 and the raw liquid 91 passing through the permeabilizer 21 by controlling the second pump 262 and the fourth pump 282 according to the flow rates detected by the second flow meter 266 and the fourth flow meter 286.

10: Filter unit 20: Osmometer unit 21: Osmometer 22: Osmotic membrane 23: First channel 24: Second channel 25: First pipeline 252: First pump 254: First flow rate and pressure sensor 26: Second pipeline 262: Second pump 264: Second flow rate and pressure sensor 266: Second flow meter 27: Third pipeline 272: Third pump 274: Third flow rate and pressure sensor 28: Fourth pipeline 282: Fourth pump 284: Fourth flow rate and pressure sensor 286: Fourth flow meter 30: Transmission pipeline 40: Control unit 90: Grinding slurry 91: Stock solution 92: Second particle 94: The Third Particle

Figure 1 is a system architecture diagram of a grinding slurry processing apparatus according to a preferred embodiment of the present invention. Figure 2 is a schematic axial cross-sectional view of a penetrator according to a preferred embodiment of the present invention. Figure 3 is a schematic diagram of the penetrator according to a preferred embodiment of the present invention in use. Figure 4 is a schematic diagram of the penetrator according to a preferred embodiment of the present invention in another state of use. Figure 5 is a flow chart of the processing method performed by the grinding slurry processing apparatus according to a preferred embodiment of the present invention. Figure 6 is a graph showing the particle size distribution of abrasive particles contained in the grinding slurry.

10: Filter unit

20: Penetration unit

21: Penetrant

25: First pipeline

252: First Pump

254: First flow pressure sensor

26: Second pipeline

262: Second Pump

264: Second flow pressure sensor

266: Second flow meter

27: Third pipeline

272: Third Pump

274: Third flow pressure sensor

28: Fourth pipeline

282: The Fourth Pump

284: Fourth flow pressure sensor

286: Fourth flow meter

30: Transmission pipeline

40: Control unit

Claims (7)

A grinding slurry processing device includes a filter unit, a permeation unit, a transmission pipeline, and a control unit. The transmission pipeline connects the filter unit and the permeation unit. The control unit is mainly composed of an electronic circuit and is coupled to the filter unit and the permeation unit to control the filter unit and the permeation unit. The filter unit is used to filter grinding slurry from an external grinding slurry source, remove a plurality of first particles having a particle size larger than a first size contained in the grinding slurry, and transmit the filtered grinding slurry to the permeation unit through the transmission pipeline. The permeation unit includes a permeator, wherein a permeation membrane is provided inside the permeator, a first channel is located on one side of the permeation membrane, and a second channel is located on the other side of the permeation membrane. One end of the first channel is connected to a first pipeline, which is connected to the transmission pipeline. The other end of the first channel is connected to a second pipeline, which is used to connect to an external storage tank. One end of the second channel is connected to a third pipeline, which is used to connect to an external raw liquid supply source. The other end of the second channel is connected to a fourth pipeline, which is used to connect to an external storage tank. The first pipeline is provided with a first pump for pumping the grinding slurry through the first channel into the second pipeline. The third pipeline is provided with a third pump for pumping the raw liquid through the second channel into the fourth pipeline. The control unit is coupled to the first pump and the third pump. The pressure in the second pipeline is greater than or equal to the pressure in the third pipeline. The first pipeline is provided with a first flow pressure sensor located between the first pump and the permeabilizer for sensing the pressure of the grinding slurry passing through the first pipeline. The third pipeline is provided with a third flow pressure sensor located between the third pump and the permeabilizer for sensing the pressure of the raw liquid passing through the third pipeline. The first flow pressure sensor and the third flow pressure sensor are respectively coupled to the control unit. Accordingly, the grinding slurry enters the second pipeline from the first pipeline through the first channel, and multiple second particles with a particle size smaller than the second size contained in the grinding slurry permeate through the permeable membrane and enter the second channel. The raw liquid supply source supplies raw liquid from the third pipeline through the second channel into the fourth pipeline, and leads each of the second particles entering the second channel into the receiving tank through the fourth pipeline. A slurry processing device as described in claim 1, wherein the second pipeline is provided with a second pump for drawing the slurry through the first channel and pumping the slurry containing multiple third particles with a particle size between the first size and the second size to the storage tank, the fourth pipeline is provided with a fourth pump for drawing the raw liquid containing multiple second particles through the second channel and pumping the raw liquid containing multiple second particles to the receiving tank, and the control unit couples the second pump and the fourth pump. The grinding slurry processing device as described in claim 2, wherein the second pipeline is provided with a second flow pressure sensor located between the second pump and the permeabilizer, which is used to sense the pressure of the grinding slurry passing through the second pipeline, and the fourth pipeline is provided with a fourth flow pressure sensor located between the fourth pump and the permeabilizer, which is used to sense the pressure of the raw liquid passing through the fourth pipeline, and the second flow pressure sensor and the fourth flow pressure sensor are respectively coupled to the control unit. The grinding slurry processing device as described in claim 3, wherein the second pipeline is provided with a second flow meter located between the second pump and the second flow pressure sensor, which is used to sense the flow of the grinding slurry passing through the second pipeline, and the fourth pipeline is provided with a fourth flow meter located between the fourth pump and the fourth flow pressure sensor, which is used to sense the flow of the raw liquid passing through the fourth pipeline, and the second flow meter and the fourth flow meter are respectively coupled to the control unit. The grinding slurry processing device as described in claim 1, wherein the permeable membrane is tubular and surrounds the first channel, and the second channel surrounds the radial outside of the permeable membrane. A processing method is performed using the grinding slurry processing apparatus of claim 1, comprising the following steps performed in sequence: introducing grinding slurry: guiding the grinding slurry from the grinding slurry source into the filtering unit; screening filtering: the filtering unit screening the grinding slurry to remove a plurality of first particles having a particle size larger than the first size contained in the grinding slurry; Permeation removal: The grinding slurry that has passed the screening and filtration step is introduced into the permeation unit to remove at least a portion of the second particles contained in the grinding slurry. The raw liquid is introduced into the permeabilizer, causing the second particles in the second channel to leave the permeabilizer, so that the grinding slurry mainly contains third particles with a particle size between the first size and the second size, thereby obtaining the grinding slurry with a homogenized particle size span. The treatment method as described in claim 6, wherein in the permeation removal step, the pressure of the polishing slurry passing through the first channel located on one side of the permeable membrane is greater than the pressure of the second channel located on the other side of the permeable membrane, thereby causing the second particles to permeate through the permeable membrane into the second channel.