KR102237311B1 - Polishing pad, preparation method thereof and preparation method of semiconductor device using same - Google Patents

Abstract

An embodiment relates to a polishing pad used in a chemical mechanical planarization (CMP) process of a semiconductor, a preparation method thereof, and a method of preparing a semiconductor device using the same. According to the embodiment, the polishing pad controls a surface roughness property of the polishing pad after polishing, thereby improving a polishing rate and significantly reducing a residue, a scratch, and a chatter mark on the surface of a wafer.

Description

Polishing pad, manufacturing method thereof, and manufacturing method of semiconductor device using the same {POLISHING PAD, PREPARATION METHOD THEREOF AND PREPARATION METHOD OF SEMICONDUCTOR DEVICE USING SAME}

The embodiments relate to a polishing pad in which surface roughness characteristics after polishing are adjusted, a method of manufacturing the same, and a method of manufacturing a semiconductor device using the same.

In the semiconductor manufacturing process, the chemical mechanical planarization (CMP) process is performed in a state in which a semiconductor substrate such as a wafer is attached to the head and brought into contact with the surface of a polishing pad formed on a platen. This is a process of mechanically flattening the irregularities on the surface of the semiconductor substrate by providing relative motion between the platen and the head while chemically reacting the surface of the semiconductor substrate by supplying

The polishing pad is an essential raw and subsidiary material that plays an important role in such a CMP process, and is generally made of a polyurethane-based resin, and a groove that plays a large flow of slurry on the surface and pores that support fine flow ( pore). Among them, the pores in the polishing pad may be formed by using a solid foaming agent having voids, a gaseous foaming agent, or a liquid foaming agent, or by generating gas through a chemical reaction.

However, the method of forming fine pores using the gaseous or liquid foaming agent has the advantage that there is no emission material that can affect during the CMP process, but it is difficult to precisely control the size and size distribution of pores and the content of pores. There may be problems. In addition, there is also a disadvantage in that it is disadvantageous in maintaining the shape of the micropores during the CMP process because there is no separate outer wall of the micropores.

On the other hand, the method of manufacturing a polishing pad using a solid foaming agent having an outer wall and voids has the advantage of being able to precisely control the shape and size distribution of pores, and the pore content, as opposed to using a gaseous or volatile liquid foaming agent. Due to the presence of the outer wall of the foaming agent, there is an advantage in maintaining the shape of the micropores during the CMP process.

However, the method of using the solid foaming agent has a problem in that it is difficult to freely control the shape of the solid foaming agent, and in the process of manufacturing by mixing the solid foaming agent into a polymer, there is a problem that the solid foaming agent may partially agglomerate in the polishing pad.

Among the important performances of the CMP process, the shape of these micropores and the pore agglomeration phenomenon that occurs partially within the polishing pad are the polishing rate, planarization, residues occurring on the wafer surface, scratches, and chatter marks. It can also affect the (chatter mark), so its control is particularly important.

Korean Patent Application Publication No. 2008-0037719

The present invention is devised to solve the problem of the prior art.

The technical problem to be solved of the present invention is to control the shape and agglomeration of fine pores to adjust the surface roughness characteristics of the polishing pad after polishing to a certain level, thereby causing residues and scratches on the wafer surface. scratch), and chatter mark characteristics, and a polishing pad capable of further improving a polishing rate, and a method of manufacturing the same.

In addition, it is intended to provide a method of manufacturing a semiconductor device useful for a layer to be polished including an oxide layer by using the polishing pad.

In order to achieve the above object, one embodiment polishes 25 dummy wafers for 60 seconds each while spraying the calcined ceria slurry on the polishing pad at a rate of 200 cc/min using a silicon oxide wafer (PETEOS wafer). And, after polishing each of the two monitoring wafers for 60 seconds, when the polishing pad after polishing was measured with an optical surface roughness meter, polishing satisfies the following equation 11 in the area material ratio curve based on the ISO 25178-2 standard. Provides a pad:

[Equation 11]

0.5≤(Spk + Svk)/Sk≤3.5

In Equation 11 above,

Spk is a reduced peak height,

The Svk is the reduced valley depth,

Sk is the core roughness depth.

In another embodiment, preparing a raw material mixture by mixing a urethane-based prepolymer, a curing agent, and a foaming agent; And injecting the raw material mixture into a mold to harden it to obtain a polishing pad, and a pile of 25 sheets while spraying the calcined ceria slurry on the polishing pad at a rate of 200 cc/min using a silicon oxide wafer (PETEOS wafer). (dummy) Polishing the wafer for 60 seconds each, polishing the two monitoring wafers for 60 seconds each, and measuring the polished polishing pad with an optical surface roughness meter, the area material ratio based on ISO 25178-2 standard It provides a method of manufacturing a polishing pad that satisfies Equation 11 in the curve.

In another embodiment, mounting a polishing pad including a polishing layer on a surface plate; And polishing the surface of the wafer by rotating relative to each other so that the polishing surface of the polishing layer and the surface of the wafer contact each other, wherein the polishing pad is calcined on a polishing pad using a silicon oxide wafer (PETEOS wafer). While spraying the ceria slurry at a rate of 200 cc/min, 25 dummy wafers were polished for 60 seconds each, and two monitoring wafers were polished for 60 seconds each, and then the polishing pad after polishing was applied to the optical surface. A method of manufacturing a semiconductor device is provided that satisfies Equation 11 in the area material ratio curve based on the ISO 25178-2 standard when measured with an illuminance meter.

The polishing pad according to the above embodiment controls the shape and agglomeration of micropores to adjust the surface roughness characteristics of the polishing pad after polishing to a certain level, thereby reducing residues and scratches generated on the wafer surface. ) And chatter mark characteristics can be improved, and the polishing rate can be further improved.

1 illustrates an example of a polishing process capable of representing deformation of a surface shape of a polishing pad and a shape of pores by shear stress according to an embodiment of the present invention.
2 is a schematic diagram illustrating a volume parameter (a) and a height parameter (b) derived from an area material ratio curve based on the ISO 25178-2 standard as measured by an optical surface roughness meter of a polishing pad.
3 is a schematic diagram showing a classifying unit in the solid foaming agent classifying and purifying apparatus according to an embodiment.
4 is a diagram illustrating an operating state diagram of a classification unit in the apparatus for classifying and purifying a solid foaming agent according to an embodiment.
5 is an exploded perspective view of filter units 30a and 30a in the solid foaming agent classification and purification apparatus according to an embodiment.
6 is a photograph showing a shape of a residue on a wafer according to an embodiment.
7 is a photograph showing a shape of a scratch on a wafer according to an embodiment.
8 is a photograph showing the shape of a chatter mark on a wafer according to an embodiment.

In the description of the following embodiments, in the case where each layer or pad, etc. is described as being formed in "on" or "under" of each layer or pad, "on" and "Under" includes both "directly" or "indirectly" formed things.

In addition, standards for the top/bottom of each component will be described based on the drawings. The size of each component in the drawings may be exaggerated for the sake of explanation, and does not mean a size that is actually applied.

In addition, all numerical ranges representing physical property values, dimensions, and the like of the constituents described in the present specification are to be understood as being modified by the term "about" in all cases unless otherwise specified.

[Polishing pad]

The polishing pad according to an embodiment of the present invention polishes 25 dummy wafers for 60 seconds each while spraying the calcined ceria slurry on the polishing pad at a rate of 200 cc/min using a silicon oxide wafer (PETEOS wafer). And, after polishing each of the two monitoring wafers for 60 seconds, the polishing pad after polishing was measured with an optical surface roughness meter, and the following equations 1 and 2 were satisfied in the area material ratio curve based on the ISO 25178-2 standard. do:

[Equation 1]

0.020≤Vmp(10)/Vvv(80)≤1.000

[Equation 2]

0.005≤Vmp(10)/Vmc(10, 80)≤2.000

In Equations 1 and 2 above,

Vmp(10) is the material volume of peaks corresponding to the top 10%,

The Vvv (80) is the void volume of the valleys corresponding to the upper 80% to 100%,

The Vmc(10, 80) is a material volume of the core corresponding to the top 10% to 80%.

The polishing pad according to another embodiment of the present invention uses a silicon oxide wafer (PETEOS wafer) to spray the calcined ceria slurry on the polishing pad at a rate of 200 cc/min, while 25 dummy wafers for 60 seconds. After polishing and polishing two monitoring wafers for 60 seconds, when the polishing pad after polishing was measured with an optical surface roughness meter, the following Equation 4 was satisfied in the area material ratio curve based on the ISO 25178-2 standard. do:

[Equation 4]

0.002≤Vmp(10)/Vv(0)≤0.100

In Equation 4 above,

The Vmp(10) is as defined above,

Vv(0) is the total void volume.

The polishing pad according to another embodiment of the present invention uses a silicon oxide wafer (PETEOS wafer) to spray the calcined ceria slurry on the polishing pad at a rate of 200 cc/min, while 25 dummy wafers are respectively deposited. After polishing each second and polishing each of the two monitoring wafers for 60 seconds, the polishing pad after polishing was measured with an optical surface roughness meter, in the area material ratio curve based on the ISO 25178-2 standard, the following equations 5 and 6 Satisfies:

[Equation 5]

Spk/Svk<1.2

[Equation 6]

0.1≤Spk/Sk≤1.1

In Equations 5 and 6 above,

Spk is a reduced peak height,

The Svk is the reduced valley depth,

Sk is the core roughness depth.

The polishing pad according to another embodiment of the present invention uses a silicon oxide wafer (PETEOS wafer) to spray the calcined ceria slurry on the polishing pad at a rate of 200 cc/min, while 25 dummy wafers are respectively deposited. After polishing each second and polishing each of the two monitoring wafers for 60 seconds, the polishing pad after polishing was measured with an optical surface roughness meter, and the following Equation 11 was satisfied in the area material ratio curve based on the ISO 25178-2 standard. do:

[Equation 11]

0.5≤(Spk + Svk)/Sk≤3.5

In Equation 11 above,

The Spk, Svk and Sk are as defined above.

According to one embodiment of the present invention, by controlling the ratio of the surface roughness characteristics of the polishing pad after polishing, particularly the volume parameter and height parameter derived from the area material ratio curve to a specific range, residues generated on the wafer surface (residue), scratch (scratch) and chatter mark (chatter mark) characteristics can be improved, it is possible to further improve the polishing rate.

Surface roughness of polishing pad after polishing

In the present specification, the surface roughness refers to the surface roughness of the polishing pad in which the surface of the polishing pad is formed by processing or polishing, and the optical surface roughness meter used in the present invention is the Contour GT model of Bruker. to be. For detailed conditions of measuring the surface roughness of the polishing pad, refer to Examples of the present specification.

When the surface roughness of the polishing pad is kept constant during the polishing process or after polishing, the polishing rate, surface residue, surface scratch, and chatter mark values of the wafer may be kept constant. In addition, as the polishing pad progresses, 1) surface cutting by a conditioner, 2) pressure and shear stress applied from the carrier (including wafers), and 3) the shape of the slurry present at the interface between the wafer and the polishing pad. As a result, damage and deformation are applied to the surface of the polishing pad, so that the surface roughness changes.

As an example, referring to FIG. 1, the polishing pad is used in a chemical mechanical planarization (CMP) process, and the compressive force in the vertical direction applied through the semiconductor substrate (wafer) 120 attached to the head 110 during the process. The surface shape of the polishing pad is deformed by shear stress in the horizontal direction generated by the rotation of the platen 130 and the platen 130.

The polishing pad has a groove in charge of large flow of the slurry 140 and pores supporting a fine flow on the surface of the polishing pad. In the polishing pad, not only the grooves on the surface but also the shape of the pores 150 are deformed by external stress, which may cause a change in the surface roughness of the polishing pad.

In particular, the degree of pore shape change or pore agglomeration that causes a change in the surface roughness of the polishing pad after polishing is the polishing rate, flattening of the wafer substrate, and residuals generated on the wafer surface, scratches, and chatter marks among the important performances of the CMP process. It can affect the back, so its control is particularly important.

The surface roughness of the polishing pad after polishing adjusted according to these characteristics may vary depending on the type of urethane-based prepolymer. In addition, the surface roughness may vary depending on the type of foaming agent (a vapor foaming agent, a liquid foaming agent, or a solid foaming agent). In addition, the surface roughness may vary depending on whether or not a purification system of a solid foaming agent is used. In addition, the surface roughness may vary depending on whether or not each ingredient is purified. In addition, the surface roughness may vary depending on the rotation speed of the mixing head, the degree of grooving, and preconditioning conditions when mixing each component, and the surface roughness may be controlled by various variables.

The surface roughness characteristic of the polishing pad according to the embodiment of the present invention is after polishing, i.e., using a silicon oxide wafer (PETEOS wafer) to spray the calcined ceria slurry on the polishing pad at a rate of 200 cc/min. ) It may be the surface roughness of the polishing pad measured after polishing the wafers for 60 seconds each and polishing the two monitoring wafers for 60 seconds each.

At this time, the dummy wafer is a wafer mainly used for experiments and tests, and the surface of the polishing pad is compressed to control the surface characteristics of the non-uniform polishing pad into a uniform shape at the beginning of the use of the polishing pad, that is, before the polishing is substantially performed. And the monitoring wafer is substantially a wafer used for the purpose of monitoring physical properties of a polishing pad after polishing.

The polishing pad can be subjected to a CMP process using the AP-300 model of CTS, and a pre break-in process is performed for 10 minutes before polishing, specifically before polishing dummy wafers, to optimize the surface condition of the pad. It may be performed for 20 minutes to condition the polishing layer of the polishing pad. For specific polishing process conditions of the polishing pad, reference may be made to Examples to be described later.

After performing the polishing process as described above, the area material ratio curve obtained using a surface roughness meter is called a bearing area curve (BAC) or an abbott-firestone curve, and the surface roughness meter It is a graph that plots the cumulative data according to the height measured for the unit area.

The parameters derived from the area material ratio curve of the surface roughness are the S parameter (hereinafter referred to as the height parameter) and the V parameter (hereinafter referred to as the volume parameter), which is a parameter converted to height. ), and in the present invention, according to the embodiment, polishing by adjusting Spk, Svk and Sk as the S parameter, and Vmp(10), Vmc(10, 80), Vvv(80) and Vv(0) as the V parameter Performance can be improved.

In this regard, FIG. 2 is a schematic diagram illustrating a volume parameter (a) and a height parameter (b) derived from the area material ratio curve when measured by an optical surface roughness meter of a polishing pad.

Hereinafter, the volume parameter and the height parameter of the surface roughness will be described in detail with reference to FIGS. 2A and 2B.

<Volume parameter of surface roughness>

The volume parameters of the surface roughness include material volume parameters (Vmp(10), Vmc(10, 80)) and void volume parameters (Vvv(80), Vv(0)).

The material volume parameter is a parameter related to the volume occupied by the actual material in the evaluation area, and the volume of the polishing pad in which the wafer and the polishing pad are directly rubbed by the pressure applied to the carrier part of the polishing apparatus during the polishing process. It is a parameter related to.

In the material volume parameter, referring to FIG. 2(a), the Vmp(10) is the material volume of peaks corresponding to the top 10%, from 0% to the percent data cut in the graph. It is the volume of the material composed of the surface that reaches the highest peak at the height (y-axis) corresponding to 10% of 100% (x-axis). Since the Vmp (10) is a parameter representing the volume of the material initially worn by the material to be polished, it may be a parameter most relevant to mechanical polishing in the CMP process.

The Vmc (10, 80) is the material volume of the core corresponding to the top 10% to 80%, and 10% and 80 of 0% to 100% (x-axis) of the percent data cut in the graph It is the volume of the material that makes up the surface texture between the heights (y-axis) corresponding to %.

Meanwhile, the void volume parameter is a parameter related to voids occupied by empty spaces in the evaluation area, and microchannels in which by-products that may cause slurries and defects/scratches can freely move between the wafer and the polishing pad interface during the polishing process. It is a parameter related to the void that plays the role of. The slurry moving through the pores causes a chemical reaction with the layer to be polished of the wafer through contact with the wafer, thereby enabling chemical polishing.

In addition, when the polishing pad pulverized material generated in the polishing process, the polishing debris of the layer to be polished, the slurry particles that have been chemically reacted, etc., grow into large particles by reacting with each other, chemical bonding or mechanical friction with the layer to be polished As a result, it may play a role of remaining as a residue on the layer to be polished or causing scratches or chatter marks on the surface of the layer to be polished.

Accordingly, the pores of the polishing pad may serve as microchannels through which these particles can easily escape without causing residues, surface scratches, or chatter marks at the interface between the polishing pad and the wafer during the polishing process.

In the void volume parameter, referring to Figure 2 (a), the Vv(0) is the total void volume, the height corresponding to 0% (x-axis) of the percent data cut in the graph It is the volume of the void bounded by the surface texture from (y-axis) to the lowest valley (100%). Since Vv(0) is the total volume of voids in which the slurry can be supported, it may be a parameter most relevant to the flow channel of the slurry in the CMP process and the fluidity of foreign matters generated during the CMP process.

The Vvv (80) is the void volume of the valleys corresponding to the upper 80% to 100%, and the height corresponding to 80% of the 0% to 100% (x-axis) of the percent data cut of the graph It is the void volume bounded by the surface texture from (y-axis) to the lowest valley.

At this time, the %, which is the reference for each of the V parameters, can be adjusted.

Therefore, the volume parameter can provide important information on the polishing performance determined by the mechanical friction and chemical reaction between the polishing pad, the wafer, and the slurry.

In the present invention, by maintaining the volume parameters of the above equations within a certain range after the polishing process and also during the polishing process, the polishing rate, residuals generated on the surface of the wafer, scratches, and chatter marks can be improved.

According to an embodiment of the present invention, the polishing pad after polishing may have a Vmp(10)/Vvv(80) of 0.020 to 1.000 in Equation 1 above. In the semiconductor manufacturing process, it is important to exhibit low surface residue, surface scratch and chattermark characteristics at a specific polishing rate. When the Vmp(10)/Vvv(80) is less than 0.020, the ratio of the polishing pad in contact with the wafer surface in the polishing process using ceria particles is low, but the ratio of the pores is relatively high, so that the slurry moves through the pores. The amount that causes a chemical reaction with the layer to be polished of the wafer through contact with the wafer increases, so that the polishing rate may increase. However, if the ratio of voids to the area where the surface of the polishing pad directly rubs is too high, the polishing pad pulverized material generated in the polishing process, the polishing debris of the layer to be polished, the slurry particles having completed chemical reactions, etc. When grown into particles, the proportion of voids is high, so the probability of bonding to the wafer surface by chemical bonding increases, and the likelihood of remaining in the form of a residue increases.

When the Vmp(10)/Vvv(80) exceeds 1.000, the ratio of the polishing pad in contact with the wafer surface in the polishing process using ceria particles is high, but the ratio of the pores is relatively low, so it moves through the pores. The amount of the resulting slurry causing a chemical reaction with the layer to be polished of the wafer through contact with the wafer decreases, so that the polishing rate may decrease. On the other hand, if the ratio of the part that directly rubs against the pores of the polishing pad surface is too high, the polishing pad pulverized material generated in the polishing process, the polishing debris of the layer to be polished, and the slurry particles that have been chemically reacted alone or with each other. When grown into particles, there is a high possibility of generating scratches or chatter marks on the wafer surface by receiving shear stress between the wafer surface and the area causing direct friction on the polishing pad surface.

Therefore, when the ratio of Vmp(10)/Vvv(80) is maintained within an appropriate range, the number of residues, scratches, and chatter marks occurring on the wafer surface can be minimized.

The polishing pad after polishing may satisfy the following Equation 1-1 or 1-2:

[Equation 　1-1]

0.030≤Vmp(10)/Vvv(80)≤0.990

[Equation 1-2]

0.040≤Vmp(10)/Vvv(80)≤0.800

In Equations 1-1 and 1-2,

The Vmp(10) and Vvv(80) are as defined above.

In addition to this, the Vmp (10) / Vvv (80) is 0.030 to 0.900. It may be from 0.050 to 0.700, 0.070 to 0.500, 0.090 to 0.400, 0.100 to 0.400, 0.200 to 0.400, 0.090 to 0.300, or more than 0.300 to 0.500 or less.

In addition, according to an embodiment of the present invention, the polishing pad after polishing may have Vmp(10)/Vmc(10, 80) of Equation 2 satisfying 0.005 to 2.000.

When the Vmp(10)/Vmc(10, 80) is less than 0.005, the contact ratio of the polishing pad to the wafer surface is low, but the ratio of the pores is relatively high, so that the slurry moving through the pores prevents contact with the wafer. Through this, a chemical reaction with the to-be-polished layer of the wafer is caused, thereby increasing chemical polishing, thereby increasing the polishing rate. On the other hand, if the ratio of voids to the area where the surface of the polishing pad directly rubs is too high, the ratio of voids is high when the polishing pad pulverized material and the layer to be polished reacts and grows into large particles generated in the polishing process. The likelihood of combining is increased and the likelihood of remaining in the form of a residue is increased.

When the Vmp(10)/Vmc(10, 80) exceeds 2.000, the contact ratio of the polishing pad to the wafer surface is high, but the ratio of the pores is relatively low, so that the slurry moving through the pores contacts the wafer. Through this, chemical polishing that causes a chemical reaction with the layer to be polished of the wafer is low, and the polishing rate may be reduced. On the other hand, if the ratio of the part that directly rubs against the pores of the polishing pad surface is too high, the polishing pad pulverized material generated in the polishing process, the polishing debris of the layer to be polished, and the slurry particles that have been chemically reacted alone or with each other. When grown into particles, there is a high possibility of generating scratches or chatter marks on the wafer surface due to pressure at the interface between the wafer surface and the area causing direct friction on the polishing pad surface.

The polishing pad after polishing may satisfy the following Equation 2-1 or Equation 2-2:

[Equation 2-1]

0.010≤Vmp(10)/Vmc(10, 80)≤1.600

[Equation 2-2]

0.015≤Vmp(10)/Vmc(10, 80)≤1.200

In Equations 2-1 and 2-2, Vmp(10) and Vmc(10, 80) are as defined above.

In addition, the Vmp (10) / Vmc (10, 80) is 0.010 to 1.000, 0.020 to 0.800, 0.020 to 0.600, 0.020 to 0.200, 0.020 to 0.100, 0.020 to 0.090, 0.030 to 0.080, 0.020 to 0.060, or more than 0.060 To 0.200 or less.

In addition, as long as the Vmp(10)/Vvv(80) and Vmp(10)/Vmc(10, 80) are each within the above range, the Vmp(10) is 0.020 to 0.900, 0.040 to 0.800, 0.060 to 0.700, It may be from 0.080 to 0.600, or from 0.100 to 0.500.

The Vvv 80 may be 0.200 to 10.000, 0.200 to 9.600, 0.200 to 2.400, 0.300 to 2.300, 0.400 to 2.200, 0.500 to 2.100, or 0.600 to 2.000.

The Vmc(10, 80) may be 0.200 to 11.000, 0.250 to 10.000, 0.250 to 7.000, 1.000 to 11.000, 1.500 to 10.500, 2.000 to 10.000, 2.500 to 9.500, or 3.000 to 9.000.

Meanwhile, according to an embodiment of the present invention, the polishing pad after polishing may satisfy Equation 3:

[Equation 3]

0.027≤Vmp(10)/{Vv(0)+Vvv(80)+Vmc(10,80)}≤3.100

In Equation 3 above,

The Vmp(10), Vv(0), Vvv(80), and Vmc(10, 80) are as defined above.

The Vv(0) may be 3.000 to 57.000, 6.000 to 54.000, 9.000 to 51.000, 12.000 to 48.000, or 15.000 to 45.000.

When the value of Equation 3 exceeds 3.100, the polishing rate in ceria CMP decreases, and surface residues, scratches, and chatter marks of the wafer may increase significantly. If the value of Equation 3 is less than 0.027, the initial polishing rate may be excessively increased due to excessive fluidity of the slurry, which may adversely affect polishing performance, and surface residues, surface scratches, and chatter marks of the wafer may increase.

In addition, the polishing pad after polishing may satisfy the following Equation 3-1 or 3-2:

[Equation 3-1]

0.042≤Vmp(10)/{Vv(0)+Vvv(80)+Vmc(10,80)}≤2.55

[Equation 3-2]

0.057≤Vmp(10)/{Vv(0)+Vvv(80)+Vmc(10,80)}≤2.02

In Equations 3-1 and 3-2,

The Vmp(10), Vv(0), Vvv(80), and Vmc(10, 80) are as defined above.

Further, according to an embodiment of the present invention, the total sum of Vv(0), Vvv(80) and Vmc(10,80) is 4.200 to 70.400, 7.800 to 66.800, 11.400 to 63.200, 12.000 to 59.600, or 18.600 to 18.600 Can be 56.000. The sum of the Vv(0), Vvv(80) and Vmc(10,80) may affect all of the mechanical polishing characteristics, friction characteristics, and slurry bearing power when the polishing pad contacts the wafer surface. The polishing pad after polishing satisfies the total sum of Vv(0), Vvv(80), and Vmc(10,80) in the above ranges, thereby improving the polishing rate, surface residues of the wafer, surface scratches, and chatter marks. .

If the total sum of the Vv(0), Vvv(80) and Vmc(10,80) is less than the above range, the initial polishing rate may be excessively increased, which may adversely affect polishing performance, and surface residues and surface scratches of the wafer And chatter marks may increase, and when the total sum of the Vv(0), Vvv(80), and Vmc(10,80) exceeds the above range, the polishing rate may decrease and the residue may significantly increase.

In addition, the polishing pad after polishing may simultaneously satisfy Equations 1-1, 2-1, and 3-1. Alternatively, the polishing pad after polishing may simultaneously satisfy Equations 1-2, 2-2, and 3-2.

According to one embodiment of the present invention, the polishing pad after polishing may satisfy Equation 4 above.

When the Vmp(10)/Vv(0) exceeds 0.100, when the polishing pad contacts the surface of the semiconductor substrate (wafer), mechanical polishing characteristics or friction characteristics are excessive, so that scratches or chatter marks may be remarkably increased. , When the Vmp(10)/Vv(0) is less than 0.002, the slurry's fluidity is excessive and the initial polishing rate is excessively increased, which may adversely affect the polishing performance. Can increase.

<Surface roughness height parameter>

Meanwhile, referring to (b) of FIG. 2, the Spk is a reduced peak height, and provides an initial contact area when the polishing pad contacts the surface of the semiconductor substrate (wafer) during the CMP process, Thus, it means a surface composed of high peaks that provides a high contact stress area (force/area). The Spk can represent the nominal height of the material that can be removed during operation.

Sk is the core roughness depth, which means the central roughness of the surface at which loads can be distributed after the surface is worn.

The Svk is a reduced valley depth, a value obtained by measuring the valley depth below the central roughness of the surface, and is related to the slurry bearing force or the polishing pad debris trapping force.

On the other hand, in Fig. 2B, SMr1 is a peak material portion and represents the ratio of the material constituting the peak structure related to Spk.

Further, SMr2 is a valley material portion and represents the percentage (100%-SMr2) of the measurement area constituting the deeper valley structure related to Svk.

According to an embodiment of the present invention, even after polishing, by maintaining any one or more of the following Equations 5 to 7 within a certain range, the polishing rate, the surface residue of the wafer, the surface scratch and the chatter mark can be improved.

Accordingly, according to an embodiment of the present invention, the polishing pad after polishing may satisfy the following Equation 5:

[Equation 5]

Spk/Svk<1.2

In Equation 5 above,

The Spk and the Svk are as defined above.

Spk/Svk of Equation 5 above can affect both mechanical polishing characteristics or friction characteristics, and slurry bearing power when the polishing pad first contacts the wafer surface, so that the polishing pad after polishing satisfies Equation 5 above, It can improve the polishing rate, the surface residue of the wafer, the surface scratch and the chatter mark.

In addition, the polishing pad after polishing may satisfy Equation 5-1 below.

[Equation 5-1]

0.2≤Spk/Svk≤1.1

In Equation 5-1,

The Spk and Svk are as defined above.

In addition, the polishing pad after polishing has a Spk/Svk of 0.2 or more and 1.0 or less. It may be 0.2 or more to 0.7 or less, 0.5 or more to less than 1.2, 0.7 or more to 1.1 or less, or 0.3 or more to 0.7 or less.

According to another embodiment of the present invention, the polishing pad after polishing may satisfy Equation 6:

[Equation 6]

0.1≤Spk/Sk≤1.1

In Equation 6 above,

The Spk and the Sk are as defined above.

Since Spk/Sk in Equation 6 affects the mechanical polishing characteristics or friction characteristics when the polishing pad first contacts the wafer surface afterwards, the polishing pad after polishing satisfies Equation 6 above, so that the polishing rate and the surface of the wafer Residues, scratches and chatter marks can be improved.

In addition, the polishing pad after polishing may satisfy Equation 6-1 below.

[Equation 6-1]

0.2≤Spk/Sk≤1.1

In Equation 6-1,

The Spk and Sk are as defined above.

In addition, the polishing pad after polishing may have the Spk/Sk of 0.2 or more to 1.0 or less, 0.3 or more to 1.1 or less, 0.4 or more to 1.0 or less, or 0.7 or more to 1.1 or less.

According to another embodiment of the present invention, the polishing pad after polishing may satisfy Equation 7:

[Equation 7]

0.2<Svk/Sk≤2.5

In Equation 7 above,

The Svk and Sk are as defined above.

Since Svk/Sk in Equation 7 affects the slurry bearing power when the polishing pad first contacts the wafer surface afterwards, the polishing pad after polishing satisfies Equation 7 above, and thus the polishing rate, the surface residue of the wafer, Surface scratches and chatter marks can be improved.

The polishing pad after polishing may satisfy Equation 7-1 below.

[Equation 7-1]

0.4≤Svk/Sk≤2.5

In Equation 7-1,

The Svk and Sk are as defined above.

In addition, the polishing pad after polishing may have the Svk/Sk of 0.5 or more and 2.4 or less, 0.9 or more and 2.4 or less, 1.6 or more and 2.4 or less, 1.6 or more and 2.0 or less, or 0.5 or more and 1.5 or less.

According to an embodiment of the present invention, the Spk may be 2 or more to 10 or less, 2.5 or more to 9.5 or less, 2 or more to 7 or less, 3 or more to 8 or less, or 5.6 or more to 10 or less.

The Sk may be 5 or more to 40 or less, 5 or more to 30 or less, 6 or more to 26 or less, 6 or more to 20 or less, 10 or more to 30 or less, or 6 or more to 10 or less.

The Svk may be greater than 11 to 22 or less, greater than 11 to 20 or less, 11.3 or more to 19.9 or less, greater than 11 to 15 or less, 13 or more to 20 or less, or 12 or more to 15 or less.

According to another embodiment of the present invention, the polishing pad after polishing may satisfy Equation 8 below.

[Equation 8]

0.3<Spk/Svk + Svk/Sk≤3.6

In Equation 8 above,

The Spk, Svk and Sk are as defined above.

The sum of Spk/Svk and Svk/Sk in Equation 8 above may affect the mechanical polishing characteristics or friction characteristics when the polishing pad first contacts the wafer surface, the slurry holding power, and the slurry holding power after the first time. When the subsequent polishing pad satisfies Equation 8, the polishing rate, the surface residue of the wafer, surface scratches, and chatter marks can be improved.

According to another embodiment of the present invention, the polishing pad after polishing may satisfy Equation 9 below.

[Equation 9]

0.3<Spk/Sk + Svk/Sk≤3.6

In Equation 9 above,

The Spk, Svk and Sk are as defined above.

The sum of Spk/Sk and Svk/Sk in Equation 9 means that the polishing pad can affect both the mechanical polishing characteristics or friction characteristics when the polishing pad contacts the wafer surface after the first time, and the slurry bearing power. When the subsequent polishing pad satisfies Equation 9, the polishing rate, the surface residue of the wafer, surface scratches, and chatter marks can be improved.

According to another embodiment of the present invention, the polishing pad after polishing may satisfy Equation 10 below.

[Equation 10]

0.45≤Spk/Sk + Svk/Sk + Spk/Svk≤4.7

In Equation 10 above,

The Spk, Svk and Sk are as defined above.

In Equation 10, the sum of Spk/Sk, Svk/Sk and Spk/Svk affects both the mechanical polishing properties or friction properties when the polishing pad first and after all contact with the wafer surface, and the slurry bearing power. Therefore, it is possible to improve the polishing rate, the surface residue of the wafer, the surface scratch, and the chatter mark by the polishing pad after polishing satisfies Equation 10 above.

In addition, the polishing pad after polishing may satisfy Equation 10-1 below.

[Equation 10-1]

0.8≤Spk/Sk + Svk/Sk + Spk/Svk≤4.6

In Equation 10-1,

The Spk, Svk and Sk are as defined above.

According to another embodiment of the present invention, the polishing pad after polishing may satisfy Equation 11 below.

[Equation 11]

0.5≤(Spk + Svk)/Sk≤3.5

In Equation 11 above,

The Spk, Svk and Sk are as defined above.

(Spk + Svk)/Sk in Equation 11 above can affect both the mechanical polishing characteristics or friction characteristics when the polishing pad contacts the wafer surface for the first time, and the slurry bearing power. By satisfying 11, it is possible to improve the polishing rate, the surface residue of the wafer, the surface scratch and the chatter mark.

In addition, the polishing pad after polishing may satisfy Equation 11-1 below.

[Equation 11-1]

0.7≤(Spk + Svk)/Sk≤3.2

In Equation 11-1,

The Spk, Svk and Sk are as defined above.

In Formulas 11 and 11-1, the total sum of Spk and Svk is greater than 13 to 32 or less, 15 or more to 30 or less, 15.5 or more to 29 or less, 15 or more to 20 or less, 17 or more to 30 or less, or 17 It may be more than 20 or less.

Surface roughness of polishing pad before polishing

According to an embodiment of the present invention, the surface roughness of the polishing pad before polishing may be within the same or similar range as the range of each parameter of the surface roughness after polishing, or may deviate from the range of each parameter of the surface roughness after polishing. . That is, no matter what the surface state of the polishing pad before polishing, as long as the surface roughness after polishing can be maintained within the above-described range, the polishing rate can be improved, and surface residues, surface scratches, and chatter marks of the wafer can be reduced. However, as the surface conditions of the polishing pad before and after polishing are similar, the polishing performance may be better.

Specifically, according to an embodiment of the present invention, the absolute value of the difference between Vmp(10)/Vvv(80) before and after polishing of the polishing pad is 0.005 to 0.800, 0.005 to 0.700, 0.010 to 0.700, 0.010 to 0.400 , 0.010 to 0.310, 0.005 to 0.030, or 0.300 to 0.700.

In addition, the absolute value of the difference between Vmp(10)/Vv(0) before and after polishing of the polishing pad may be 0.002 to 0.087, 0.002 to 0.070, 0.002 to 0.020, or 0.01 to 0.09.

When the absolute value of the difference between Vmp(10)/Vvv(80) or Vmp(10)/Vv(0) before and after polishing of the polishing pad satisfies the above range, the surface roughness both before and after polishing It is constant so that the polishing performance can be improved.

In addition, the absolute value of the difference between Svk/Sk or Spk/Sk before and after polishing of the polishing pad may be 1.5 or less, respectively.

Specifically, the absolute value of the difference between Svk/Sk before and after polishing of the polishing pad is 0.1 to 1.5, 0.2 to 1.5, 0.1 to 1.0, 0.1 to 0.7, or 0.8 to 1.5,

The absolute value of the difference between Spk/Sk before and after polishing of the polishing pad may be 0 to 0.6, 0 to 0.5, less than 0 to 0.4, or 0.4 to 0.6.

When the absolute value of the difference between Svk/Sk or Spk/Sk before and after polishing of the polishing pad satisfies the above range, both before and after polishing, the surface roughness is constant, so that polishing performance may be improved.

[Manufacturing method of polishing pad]

A method of manufacturing a polishing pad according to an embodiment of the present invention includes preparing a raw material mixture by mixing a urethane-based prepolymer, a curing agent, and a foaming agent; And injecting the raw material mixture into a mold to harden it to obtain a polishing pad, and a pile of 25 sheets while spraying the calcined ceria slurry on the polishing pad at a rate of 200 cc/min using a silicon oxide wafer (PETEOS wafer). (dummy) Polishing the wafer for 60 seconds each, polishing the two monitoring wafers for 60 seconds each, and measuring the polished polishing pad with an optical surface roughness meter, the area material ratio based on ISO 25178-2 standard In the curve, Equation 11 may be satisfied.

A method of manufacturing a polishing pad according to another embodiment of the present invention includes preparing a raw material mixture by mixing a urethane-based prepolymer, a curing agent, and a foaming agent; And injecting the raw material mixture into a mold to harden it to obtain a polishing pad, and a pile of 25 sheets while spraying the calcined ceria slurry on the polishing pad at a rate of 200 cc/min using a silicon oxide wafer (PETEOS wafer). (dummy) Polishing the wafer for 60 seconds each, polishing the two monitoring wafers for 60 seconds each, and measuring the polished polishing pad with an optical surface roughness meter, the area material ratio based on ISO 25178-2 standard In the curve, Equations 1 and 2 may be satisfied.

A method of manufacturing a polishing pad according to another embodiment of the present invention includes the steps of preparing a raw material mixture by mixing a urethane-based prepolymer, a curing agent, and a foaming agent; And injecting the raw material mixture into a mold to harden it to obtain a polishing pad, and spraying the calcined ceria slurry on the polishing pad at a rate of 200 cc/min using a silicon oxide wafer (PETEOS wafer) for 60 seconds. After polishing 25 dummy wafers, polishing 2 monitoring wafers for 60 seconds, and measuring the polished polishing pad with an optical surface roughness meter, the area material ratio based on ISO 25178-2 standard Equation 4 above can be satisfied in the curve.

A method of manufacturing a polishing pad according to another embodiment of the present invention includes preparing a raw material mixture by mixing a urethane-based prepolymer, a curing agent, and a foaming agent; And injecting the raw material mixture into a mold to harden it to obtain a polishing pad, and a pile of 25 sheets while spraying the calcined ceria slurry on the polishing pad at a rate of 200 cc/min using a silicon oxide wafer (PETEOS wafer). (dummy) Polishing the wafer for 60 seconds each, polishing the two monitoring wafers for 60 seconds each, and measuring the polished polishing pad with an optical surface roughness meter, the area material ratio based on ISO 25178-2 standard In the curve, Equations 5 and 6 may be satisfied.

The polishing pad includes a polishing layer comprising a cured product formed from a composition comprising a urethane-based prepolymer, a curing agent, and a foaming agent, and the foaming agent includes at least one selected from the group consisting of a solid foaming agent, a liquid foaming agent, and a gaseous foaming agent. I can. Alternatively, the foaming agent may include a solid foaming agent, a gaseous foaming agent, or a mixed foaming agent thereof.

Hereinafter, each component included in the raw material mixture will be described in detail.

Urethane prepolymer

The surface roughness of the polishing pad after polishing for the purpose of the present invention can be adjusted by different types of urethane-based prepolymers.

The urethane-based prepolymer may be prepared by reacting an isocyanate compound and a polyol.

In general, a prepolymer refers to a polymer having a relatively low molecular weight in which the degree of polymerization is stopped in an intermediate step to facilitate molding in manufacturing a kind of final molded product. The prepolymer may be formed by itself or after reacting with another polymerizable compound, and for example, the prepolymer may be prepared by reacting an isocyanate compound with a polyol.

The isocyanate compounds used in the preparation of the urethane-based prepolymer are, for example, toluene diisocyanate (TDI), naphthalene-1,5-diisocyanate (naphthalene-1,5-diisocyanate), and paraphenylene diisocyanate ( p-phenylene diisocyanate), toridine diisocyanate, 4,4'-diphenyl methane diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate It may be one or more isocyanates selected from the group consisting of isocyanate (dicyclohexylmethane diisocyanate) and isophorone diisocyanate, but is not limited thereto.

Polyols that can be used in the preparation of the urethane-based prepolymer are, for example, polyether polyols, polyester polyols, polycarbonate polyols, and acrylic polyols. It may be one or more polyols selected from the group consisting of, but is not limited thereto. The polyol may have a weight average molecular weight (Mw) of 300 g/mol to 3,000 g/mol.

The urethane-based prepolymer may have a weight average molecular weight of 500 g/mol to 3,000 g/mol. Specifically, the urethane-based prepolymer may have a weight average molecular weight (Mw) of 600 g/mol to 2,000 g/mol, or 800 g/mol to 1,000 g/mol.

As an example, the urethane-based prepolymer may be a polymer having a weight average molecular weight (Mw) of 500 g/mol to 3,000 g/mol polymerized using toluene diisocyanate as an isocyanate compound and polytetramethylene ether glycol as a polyol. .

The urethane-based prepolymer may have an isocyanate end group content (NCO%) of 8 wt% to 10 wt%, 8.5 wt% to 9.5 wt%, or 8.8 wt% to 9.4 wt%.

When the NCO% satisfies the above range, it is possible to maintain a constant surface roughness of the polishing pad after polishing for the purpose of the present invention, thereby improving the polishing rate and the surface residues, surface scratches, and chatter mark characteristics of the wafer. have.

blowing agent

In the polishing pad according to an embodiment of the present invention, the plurality of pores may be derived from a foaming agent.

The foaming agent may include one or more foaming agents selected from the group consisting of a solid foaming agent, a gaseous foaming agent, and a liquid foaming agent.

In addition, depending on the type of gaseous foaming agent, liquid foaming agent or solid foaming agent, the average particle diameter of the solid foaming agent, and the presence or absence of a purification system for the solid foaming agent, it is possible to control the shape change of the pores or the degree of agglomeration of pores occurring in the polishing pad After polishing, the surface roughness of the polishing pad can be controlled.

Solid foaming agent

Depending on the type, shape, or physical properties of the solid foaming agent, it is possible to control the shape of the fine pores and the pore agglomeration phenomenon, and thus, the surface roughness of the polishing pad after polishing can be adjusted.

The solid foaming agent may be a microcapsule that has been thermally expanded (size-controlled), and may be a microballoon structure having an average particle diameter of 5 µm to 200 µm. The thermally expanded (size-adjusted) microcapsules may be obtained by heating and expanding the thermally expandable microcapsules.

The thermally expandable microcapsules include an outer shell containing a thermoplastic resin; And a foaming agent encapsulated inside the outer shell. The thermoplastic resin may be at least one selected from the group consisting of vinylidene chloride-based copolymers, acrylonitrile-based copolymers, methacrylonitrile-based copolymers, and acrylic copolymers. Furthermore, the foaming agent enclosed in the inside may be at least one selected from the group consisting of hydrocarbons having 1 to 7 carbon atoms. Specifically, the foaming agent enclosed in the inside of ethane, ethylene, propane, propene, n-butane, isobutene, butene , Isobutene, n-pentane, isopentane, neopentane, n-hexane, heptane, petroleum ether, etc. Low molecular weight hydrocarbons; Trichlorofluoromethane (CCl ₃ F), dichlorodifluoromethane (CCl ₂ F ₂ ), chlorotrifluoromethane (CClF ₃ ), tetrafluoroethylene (CClF ₂ -CClF) Chlorofluoro hydrocarbons such as _{2 );} And tetraalkylsilanes such as tetramethylsilane, trimethylethylsilane, trimethylisopropylsilane, and trimethyl-n-propylsilane.

The solid foaming agent can precisely control the shape and size distribution of pores, and the content of pores, and can maintain the shape of micropores well during the CMP process due to the presence of the outer wall of the solid foaming agent. However, since the solid foaming agent is a micro-balloon structure, the density is low and the size is small, so the surface tension is large, and thus thin and small spherical materials are liable to be aggregated. Therefore, even if the size of the solid foaming agent is controlled, it may not be easy to control the shape of the solid foaming agent, as well as the shape of the fine pores or the aggregation phenomenon of the pores.

According to an embodiment of the present invention, by using the solid foaming agent purified by a purification system, the average particle diameter of the solid foaming agent can be controlled, as well as dispersing them without clumping together, and a solid state having a non-uniform shape. Foaming agents can also be filtered out. Accordingly, the shape and agglomeration of micropores can be controlled, and the surface roughness of the polishing pad after polishing can be controlled. Accordingly, the average particle diameter of the solid foaming agent, the standard deviation or density of the average particle diameter, and the like may vary according to the use of the purification system of the solid foaming agent.

For example, the average particle diameter (D50) of the purified solid foaming agent may be 5 μm to 200 μm. Here, the D50 may refer to the volume particle diameter of the 50th percentile (medium) of the particle diameter distribution. More specifically, the solid foaming agent may have a D50 of 7 μm to 100 μm. Even more specifically, the solid foaming agent is 10 μm to 50 μm; 15 μm to 45 μm; Alternatively, it may have a D50 of 20 μm to 40 μm.

The solid foaming agent purification system may filter out particles having an average particle diameter of the solid foaming agent that is too small or too large to satisfy the average particle diameter of the above range, and selectively control the average particle diameter of the solid foaming agent in the above range according to the required purpose. can do.

When the D50 of the solid foaming agent satisfies the above range, the polishing rate and flatness may be further improved. If the D50 of the solid foaming agent is less than the above range, the number average diameter of the pores decreases and may affect the polishing rate and flatness, and if it exceeds the above range, the number average diameter of the pores becomes too large to affect the polishing rate and flatness. It can have an adverse effect.

In the case of using the solid foaming agent purified by the solid foaming agent purification system as described above, the surface roughness of the polishing pad can be uniformly maintained after polishing.

The solid foaming agent may be used in an amount of 0.5 parts by weight to 5 parts by weight based on 100 parts by weight of the raw material mixture. Specifically, the solid foaming agent is used in an amount of 0.6 to 2.5 parts by weight, 1 to 2.5 parts by weight, 1.5 to 2.5 parts by weight, or 1.8 to 2.3 parts by weight based on 100 parts by weight of the urethane-based prepolymer. I can.

In the manufacture of the polishing pad of the present invention, a solid foaming agent may be used alone as a foaming agent, or may be used in combination with a gaseous foaming agent and a volatile liquid foaming agent according to desired properties.

Solid blowing agent purification system

The solid foaming agent purification system can implement the average particle diameter (D50) of the solid foaming agent in the above range, and various purification systems can be used as long as the surface roughness of the polishing pad desired in the present invention can be satisfied.

According to an embodiment of the present invention, a solid foaming agent classification and purification apparatus was used as the solid foaming agent purification system.

In the solid foaming agent classification and purification apparatus according to an embodiment, a classification unit for classifying the supplied solid foaming agent into first microspheres and second microspheres, and the first microspheres classified by being connected to the classification unit are introduced and stored. It includes a storage unit capable of being discharged, and a filter unit disposed in the moving path of the solid foaming agent or the first microspheres to separate the metallic material from the filtering target including the solid foaming agent or the first microspheres.

3 is a schematic diagram showing a classifier according to an embodiment, and FIG. 4 is a diagram illustrating an operation state diagram of the classifier of FIG. 3.

3 and 4, the classification unit 50 includes a classification housing 51 having a classification space 511 formed therein, a gas supply hole 515 connected to the classification space 511, and a classification space 511. It includes a classification discharge hole connected to. The classification unit 50 may further include a vortex generating member 53 positioned in the classification space 511 and disposed adjacent to the gas supply hole 515. The classification unit 50 may further include a vibration generating unit 56 disposed in the classification housing 51. The classification unit 50 may further include a classification and stirring unit.

Classification of the solid foaming agent introduced into the classification space 511 through one of the classification inflow holes 512 may be performed as follows. In the classification space 511, a flowing gas is supplied to classify the solid foaming agent. The flowing gas introduced into the classification space 511 flows in the direction of the gas discharge hole 516 while passing through the vortex generating member 53. At this time, the flowing gas flows while generating rotation or vortex (dashed arrow in the classification space 511 of FIG. 10: indicated by A). The flowing gas flows to the top where the gas discharge hole 516 is formed. The solid foaming agent introduced into the classification space 511 rises along the flowing gas and then falls within the classification space 511 due to a downward flow that occurs due to weakening of the flow of the flowing gas or rotational force or vibration transmitted from the outside. It can be accelerated (in Fig. 10, the flow of the solid foaming agent is indicated by a double-dashed line arrow: B, and a vibration arrow: C). At this time, the flow of air in the classification space 511 forms a circulating flow of air cells, so that when the particles are heavy or too light compared to the size of the solid foaming agent, or when the shape of the particles is remarkably different, the speed of ascending or descending Is different and classified. That is, the solid foaming agent floats in the classification space 511 according to the flow of the flowing gas, and the solid foaming agent descends at different speeds according to its weight and size according to the influence of gravity and vibration, and is classified and recovered according to size. I can.

In this way, the solid foaming agents rising or falling under the influence of flowing gas, etc. are classified into the classification housing 51 through the first microsphere discharge hole 513 and the second microsphere discharge hole 514 formed according to the height of the classification housing 51. Can be discharged out of each.

A gas discharge hole 516 through which the flowing gas introduced into the classification space 511 is discharged may be formed on the upper surface of the classification housing 51, and foreign substances contained in the discharged flowing gas may be formed in the gas discharge hole 516. , An exhaust filter 54 for filtering residual microspheres, etc. may be disposed.

In one embodiment, the vibration process is vertical vibration moving vertically around the central axis 511a on the classification housing 51 through the vibration generating unit 56, horizontal vibration moving left and right, or both vertically and horizontally. Vertical and horizontal vibrations that apply vibration can be applied sequentially or simultaneously. In addition, the vibration process is a rotation method in which the classification housing 51 is rotated clockwise or counterclockwise based on the central axis 511a, or rotated in a clockwise and counterclockwise direction repeatedly. I can. For example, the vibration applied to the vibration process may be a vibration of 100 to 10,000 Hz, for example, a vibration of 500 to 5,000 Hz, and, for example, a vibration of 700 to 3,500 Hz. When the vibration is applied in such a range, the solid foaming agent can be more efficiently classified.

Due to the characteristics of a relatively small and light solid foaming agent, it is possible to classify by the difference in the speed at which the solid foaming agent rises and falls due to the rise of the flowing gas, but hollow microspheres that do not rise and fall easily by the flowing gas can be lowered faster by vibration. . That is, this vibration process can be carried out in a manner of down force vibrating that promotes the falling of the solid foaming agent in the classification space 511, and if the vibration process proceeds further, more efficient and effective classification can be performed, The polishing layer formed through such a process can manufacture a semiconductor substrate (wafer) with few surface defects such as surface residues, surface scratches, and chatter marks of the wafer.

The particle diameter of the solid foaming agent to be classified may be adjusted by the flow rate of the injected flowing gas, the position of the first microsphere discharge hole 513, the degree of vibration, and the like. As a result, the solid foaming agent can be classified into first microspheres having an average particle diameter of about 5 μm to about 200 μm and second microspheres having an average particle diameter of less than about 5 μm. Among the solid foaming agents, those that are damaged or have an excessively high density may be the third microspheres. Accordingly, in the classification space 511, the solid foaming agent may be classified into first to third microspheres. The particle size of the classified solid foaming agent may vary depending on the design of the polishing pad.

5 is an exploded perspective view of the filter units 30a and 30b according to an embodiment. 3 and 5, the filter units 30a and 30b may be disposed at a front end, a rear end, or a front and rear end of the classification unit. The filter unit 30b disposed at the rear end of the classification unit may remove metal components in the first microspheres separated through the classification space 511. The filter part 30a disposed at the front end of the classifying part may remove metal components from the solid foaming agent before flowing into the classifying part 50.

5, the filter units 30a and 30b are disposed to be separated in the filter housing 31 and the filter housing 31 in which the filter space 311 through which the solid foaming agent passes is formed. And a filter cover 32 that opens and closes the filter space 311 and a filter member 33 disposed in the filter space 311 and generating magnetic force.

The filter housing 31 may have a filter inlet 312 connected to the pipes 10a and 10c. The solid foaming agent is introduced into the filter space 311 through the filter inlet 312, and may move in an open direction while making a pivotal motion along the periphery of the filter space 311. The filter member 33 is located in the filter space 311, and it is possible to induce vortex generation in the flow of the solid foaming agent.

In one embodiment, a filter outlet 321 connected to the filter space 311 may be formed in the filter cover 32. In another embodiment, the filter outlet 321 may be formed around the filter housing 31. The location of the filter outlet 321 may vary depending on the type or density of the filtering target. The solid foaming agent passed through the filter space 311 through the filter inlet 312 may be discharged to the outside of the filter housing 31 through the filter outlet 321.

The filter member 33 may include a mounting portion 331 positioned in the filter space 311 and a magnet 332 disposed in the mounting portion 331. In one embodiment, the magnet 332 may be disposed inside the mounting portion 331. The magnet 332 may include a box stone or an electromagnet. The magnet may be a neodymium magnet. The magnet may have a magnetic force of 10,000 Gauss to 12,000 Gauss. A magnetic field is formed around the mounting portion 331 by the magnet, and a metallic material is attached to the magnet. The metallic material contained in the solid foaming agent that rotates in the filter space 311 by magnetic force may adhere to the outer periphery of the mounting portion 331. The metallic material mixed with the filtering target passing through the filter space 311 may be separated through the magnet 332. Through the filter unit, a purified solid foaming agent or first microspheres may be provided.

As the solid foaming agent is processed through the classifying part, roughness control performance may be improved in surface processing of a polishing pad manufactured including the same. If the size of the solid foaming agent is too small, agglomeration of the composition for manufacturing the polishing pad may occur, and if the size of the solid foaming agent is too large, it is difficult to control the pore size and thus the surface properties of the polishing pad may be deteriorated. Therefore, as a solid foaming agent of an appropriate size is deduced through the classification part, agglomeration in the composition for manufacturing the polishing pad can be prevented, and further, a uniform and suitable roughness characteristic of a depth/width can be realized on the surface of the polishing pad. have.

In addition, high-density metallic foreign matter in the solid foaming agent, agglomerated lumps using this as a seed, etc., affect the surface condition of the polishing pad and act as an obstacle to processing the desired level of roughness characteristics. Therefore, by using the solid foaming agent from which the metal component has been removed through the filter part, it is possible to minimize foreign matters and lumps with high density to be included in the polishing pad, and as a result, semiconductor substrates etc. polished with polishing pads having excellent surface characteristics The effect of quality improvement can be secured, such as remarkably reducing product defects.

Gaseous blowing agent

The surface roughness of the polishing pad after polishing for the purpose of the present invention can be adjusted by varying the type of gaseous foaming agent.

The gaseous foaming agent may include an inert gas, and the gaseous foaming agent may form pores by mixing the urethane-based prepolymer, a curing agent, a solid foaming agent, a reaction rate control agent, and a silicone-based surfactant into a reaction process. The type of the inert gas is not particularly limited as long as it does not participate in the reaction between the prepolymer and the curing agent. For example, the inert gas _{may be at least one selected from the group consisting of nitrogen gas (N 2} ), argon gas (Ar), and helium gas (He). Specifically, the inert gas may be nitrogen gas (N ₂ ) or argon gas (Ar).

The gaseous blowing agent may be added in a volume corresponding to the total volume of the raw material mixture, specifically, 5% to 30% by volume of the total volume of the urethane-based prepolymer, the blowing agent, the reaction rate control agent, and the curing agent. Specifically, the gaseous blowing agent is 5% to 30% by volume, 5% to 25% by volume, 5% to 20% by volume, 5% to 18% by volume, 6% by volume of the total volume of the raw material mixture. It may be added in a volume corresponding to 15% by volume, 6% by volume to 13% by volume, or 7.5% by volume to 10% by volume.

Liquid foaming agent

The surface roughness of the polishing pad after polishing for the purpose of the present invention can be adjusted by different types and mixing processes of the liquid foaming agent.

The liquid foaming agent may be introduced into the process of reacting by mixing the prepolymer and the curing agent to form pores, and does not participate in the reaction between the prepolymer and the curing agent. In addition, the liquid foaming agent is physically vaporized by heat generated during the reaction by mixing the prepolymer and the curing agent to form pores.

The liquid foaming agent may include two or more volatile liquid foaming agents having different boiling points. Specifically, the volatile liquid foaming agent may include one or more low-boiling liquid foaming agents and one or more high-boiling liquid foaming agents.

The volatile liquid foaming agent does not react with an isocyanate group, an amide group, and an alcohol group, and may be liquid at 25°C. Specifically, the volatile liquid foaming agent is trichlorofluoromethane, 2,2-dichloro1,1,1-trifluoroethane (2,2-dichloro-1,1,1-trifluoroethane), 1, 1-dichloro-1-fluoroethane, cyclopentane, n-pentane, cyclohexane, n-butyl acetate acetate), bis(nonafluorobutyl)(trifluoromethyl)amine (bis(nonafluorobutyl)(trifluoromethyl)amine); And perfluoro compounds such as perfluorotributylamine, perfluoro-N-methylmorpholine, fluorotripentylamine, and perfluorohexane. It can be selected from the group.

Commercially available products of the perfluoro compound include FC-40 (3M company), FC-43 (3M company), FC-70 (3M company), FC-72 (3M company), FC-770 (3M company), FC -3283 (3M company), FC-3284 (3M company), and the like.

The low-boiling liquid foaming agent may be vaporized at the beginning of the reaction to form mesopores having an average particle diameter of 45 to 90 µm. Specifically, the low boiling point liquid foaming agent may have a boiling point of 30 to 100 °C at 1 atmosphere. More specifically, the low boiling point liquid foaming agent may have a boiling point of 40 to 70 °C at 1 atmosphere. More specifically, the low boiling point liquid blowing agent is trichlorofluoromethane, 2,2-dichloro-1,1,1-trifluoroethane, 1,1-dichloro-1-fluoroethane, cyclopentane, cyclohexane, It may be one or more selected from the group consisting of n-pentane, perfluoro-N-methylmorpholine, and perfluorohexane. Commercially available products of the low-boiling liquid foaming agent include FC-72 (3M), FC-770 (3M), FC-3284 (3M), and the like.

The high boiling point liquid foaming agent may be vaporized with a delay to form micropores having an average particle diameter of 20 to 50 µm. Specifically, the high boiling point liquid foaming agent may have a boiling point of 100 to 250 °C at 1 atmosphere. More specifically, the high boiling point liquid foaming agent may have a boiling point of 100 to 200 °C at 1 atmosphere. More specifically, the high boiling point liquid blowing agent may be at least one selected from the group consisting of n-butyl acetate, bis(nonafluorobutyl)(trifluoromethyl)amine, perfluorotributylamine, and perfluorotripentylamine. have. Commercially available products of the high boiling point liquid foaming agent include FC-40 (manufactured by 3M), FC-43 (manufactured by 3M), FC-70 (manufactured by 3M), and FC-3283 (manufactured by 3M).

The low-boiling liquid foaming agent and the high-boiling liquid foaming agent may have a boiling point difference of 20 to 80° C., specifically, 50 to 80° C. between each other. Specifically, as a combination of a low boiling point liquid foaming agent and a high boiling point liquid foaming agent, a combination of cyclopentane and nbutyl acetate, trichlorofluoromethane and bis(nonafluorobutyl)(trifluoromethyl)amine, and the like may be mentioned.

The volatile liquid foaming agent may include a low boiling point liquid foaming agent and a high boiling point liquid foaming agent in a molar ratio of 1: 0.5 to 2. Specifically, the volatile liquid foaming agent may include a low boiling point liquid foaming agent and a high boiling point liquid foaming agent in a molar ratio of 1: 0.8 to 1.2. The liquid foaming agent may be added in an amount of 1 to 10 parts by weight based on 100 parts by weight of the raw material mixture. In addition, the liquid foaming agent may be added in an amount of 2 to 8 parts by weight based on 100 parts by weight of the raw material mixture.

Hardener

The curing agent may be one or more of an amine compound and an alcohol compound. Specifically, the curing agent may include one or more compounds selected from the group consisting of aromatic amines, aliphatic amines, aromatic alcohols, and aliphatic alcohols.

For example, the curing agent is 4,4'-methylenebis(2-chloroaniline) (MOCA), diethyltoluenediamine, diaminodiphenyl methane, diaminodiphenyl sulphone ), m-xylylene diamine, isophoronediamine, ethylenediamine, diethylenetriamine, triethylenetetramine, polypropylenediamine, Polypropylenetriamine, ethyleneglycol, diethyleneglycol, dipropyleneglycol, butanediol, hexanediol, glycerin, trimethylolpropane And it may be at least one selected from the group consisting of bis (4-amino-3-chlorophenyl) methane (bis (4-amino-3-chlorophenyl) methane).

The urethane-based prepolymer and the curing agent may be mixed in a molar equivalent ratio of 1: 0.8 to 1.2, or 1: 0.9 to 1.1, based on the number of moles of reactive groups in each molecule. Here, "based on the number of moles of each reactive group" means, for example, based on the number of moles of isocyanate groups in the urethane-based prepolymer and the number of moles of reactive groups (amine groups, alcohol groups, etc.) of the curing agent. Accordingly, the urethane-based prepolymer and the curing agent are added at an amount that satisfies the molar equivalent ratio exemplified above, and the injection rate is adjusted to be added per unit time, so that the urethane-based prepolymer and the curing agent may be added at a constant rate in the mixing process.

The curing agent may be used in an amount of 3.0 parts by weight to 40 parts by weight based on 100 parts by weight of the raw material mixture. Specifically, the curing agent may be used in an amount of 5.0 parts by weight to 35 parts by weight based on 100 parts by weight of the raw material mixture. Specifically, the curing agent may be used in an amount of 7.0 parts by weight to 30 parts by weight of 100 parts by weight of the raw material mixture.

Surfactants

The raw material mixture may further include a surfactant. The surfactant may serve to prevent overlapping and coalescence of formed pores. Specifically, a silicone-based nonionic surfactant is suitable as the surfactant, but may be variously selected according to physical properties required for the polishing pad.

As the silicone-based nonionic surfactant, a silicone-based nonionic surfactant having a hydroxyl group may be used alone or together with a silicone-based nonionic surfactant having no hydroxyl group.

The silicone-based nonionic surfactant having a hydroxyl group is not particularly limited as long as it has excellent compatibility with an isocyanate-containing compound and an active hydrogen compound and is widely used in the polyurethane technology field. A commercially available material of the silicone-based nonionic surfactant having a hydroxyl group is, for example, DOW CORNING 193 (silicone glycol copolymer, liquid; specific gravity at 25° C.: 1.07; viscosity at 20° C.: 465 mm 2 /s) ; Flash point: 92°C) (hereinafter referred to as DC-193) and the like.

A commercially available material of the silicone-based nonionic surfactant that does not have a hydroxyl group is, for example, DOW CORNING 190 (silicone glycol copolymer, Gardner color number: 2; specific gravity at 25° C.: 1.037; viscosity at 25° C.: 2000 ㎟/s; Flash point: 63 ℃ or higher; Inverse solubility Point (1.0% water solution): 36 ℃) (hereinafter referred to as DC-190).

The surfactant may be included in an amount of 0.1 to 2 parts by weight based on 100 parts by weight of the raw material mixture. Specifically, the surfactant may be included in an amount of 0.2 to 1.8 parts by weight, 0.2 to 1.7 parts by weight, 0.2 to 1.6 parts by weight, or 0.2 to 1.5 parts by weight based on 100 parts by weight of the raw material mixture. When the surfactant is included in an amount within the above range, pores derived from the gaseous blowing agent may be stably formed and maintained in the mold.

Reaction and pore formation

The urethane-based prepolymer and the curing agent are mixed and then reacted to form a solid polyurethane to form a sheet or the like. Specifically, the isocyanate terminal group of the urethane-based prepolymer may react with an amine group, an alcohol group, and the like of the curing agent. At this time, a foaming agent such as a solid foaming agent is evenly dispersed in the raw material without participating in the reaction between the urethane-based prepolymer and the curing agent to form a plurality of pores.

Molding

The molding may be performed using a mold. Specifically, the raw material mixture sufficiently stirred in the mixing head or the like may be discharged into the mold to fill the inside of the mold.

The sphericity control of a plurality of pores included in the polishing pad according to an exemplary embodiment of the present invention may be performed using a rotational speed of the mixing head and a system for purifying a solid foaming agent. Specifically, in the process of mixing and dispersing the urethane-based prepolymer, the solid foaming agent, and the curing agent, the rotation speed of the mixing head, for example, 500 rpm to 10000 rpm, 700 rpm to 9000 rpm, 900 rpm to 8000 rpm, 900 by the mixing system. It can be stirred at a rotational speed of rpm to less than 7000 rpm, or 1000 rpm to 5000 rpm. Alternatively, in the process of mixing and dispersing the urethane-based prepolymer, the solid foaming agent, and the curing agent, the solid foaming agent may be purified by a purification system.

The reaction between the urethane-based prepolymer and the curing agent is completed in the mold, so that a molded article in the form of a cake solidified in the shape of the mold can be obtained.

Thereafter, the obtained molded article can be appropriately sliced or cut to be processed into a sheet for manufacturing a polishing pad. As an example, after molding in a mold having a height of 5 to 50 times the thickness of the polishing pad to be finally manufactured, the molded body may be sliced at equal thickness intervals to manufacture a plurality of sheets for polishing pads at once. In this case, a reaction retarding agent can be used as a reaction rate control agent to secure a sufficient solidification time, and accordingly, a sheet is manufactured even if the height of the mold is configured to be 5 to 50 times the thickness of the final manufactured polishing pad. May be possible. However, the sliced sheets may have pores of different diameters depending on the molded position in the mold. That is, a sheet molded from the lower part of the mold may have pores having a fine diameter, whereas a sheet molded from the upper part of the mold may have pores having a larger diameter than that of a sheet formed from the lower part.

Therefore, preferably, in order to have pores of a uniform diameter even for each sheet, a mold capable of manufacturing one sheet by one molding may be used. To this end, the height of the mold may not be significantly different from the thickness of the polishing pad to be finally manufactured. For example, the molding may be performed using a mold having a height corresponding to 1 to 3 times the thickness of the final manufactured polishing pad. More specifically, the mold may have a height of 1.1 to 4.0 times, or 1.2 to 3.0 times the thickness of the final manufactured polishing pad. At this time, a reaction accelerator may be used as a reaction rate control agent in order to form pores having a more uniform particle size. Specifically, the polishing pad made of one sheet may have a thickness of 1 mm to 10 mm. Specifically, the polishing pad is 1 mm to 9 mm, 1 mm to 8.5 mm, 1.5 mm to 10 mm, 1.5 mm to 9 mm, 1.5 mm to 8.5 mm, 1.8 mm to 10 mm, 1.8 mm to 9 mm, or It may have a thickness of 1.8 mm to 8.5 mm.

Thereafter, each of the top and bottom of the molded body obtained from the mold can be cut. For example, each of the upper and lower ends of the molded body can be cut by 1/3 or less of the total thickness of the molded body, by 1/22 to 3/10, or by 1/12 to 1/4. have.

As a specific example, the molding is performed using a mold having a height corresponding to 1.2 to 2 times the thickness of the polishing pad to be finally manufactured, and after the molding, each of the upper and lower ends of the molded body obtained from the mold is the total thickness of the molded body. It may further include a process of cutting by 1/12 to 1/4 of the.

The manufacturing method may further include a step of processing a groove on the surface after cutting the surface, an adhesion step with a lower layer, an inspection step, a packaging step, and the like. These processes can be performed in the manner of a conventional polishing pad manufacturing method.

In addition, the polishing pad manufactured by the above-described manufacturing method exhibits all of the characteristics of the polishing pad according to the above-described embodiment.

[Physical properties of polishing pad]

As described above, the polishing pad according to the embodiment can improve the polishing rate by controlling each parameter of the surface roughness of the polishing pad after polishing, and reduce surface residues, surface scratches, and chatter marks of the wafer. I can.

Specifically, when polishing a silicon wafer on which a silicon oxide film is formed using a calcined ceria slurry, the polishing pad has a polishing rate of 2600 Å/min to 3300 Å/min, and 2850 Å/min to 3200 Å/ Min, 2900 Å/min to 3100 Å/min or more, or 2900 Å/min to 3000 Å/min.

In addition, 25 dummy wafers were polished for 60 seconds each while spraying calcined ceria slurry on the polishing pad at a rate of 200 cc/min using a silicon oxide wafer (PETEOS wafer), and two monitoring wafers. After polishing each for 60 seconds, the number of chatter marks of the monitoring wafer may be 5 or less, 1 to 5, 1 to 4, or 1 to 3.

In addition, the number of scratches on the surface of the monitoring wafer after polishing is 200 or less. It may be 1 to 200, 1 to 180, 1 to 160, or 1 to 150.

In addition, the number of surface residues of the monitoring wafer after polishing may be 100 or less, 90 or less, 86 or less, or 80 or less.

Meanwhile, the polishing pad includes a plurality of pores.

In the polishing pad according to the embodiment of the present invention, the average diameter of the plurality of pores may be 5 μm to 200 μm. In addition, the average diameter of the plurality of pores may be 7 µm to 100 µm, 10 µm to 50 µm, 10 µm to 32 µm, or 20 µm to 32 µm. The average diameter of the plurality of pores was calculated as the number average value of the pore diameters. For example, an image area of the polishing pad was observed at 200 times using a scanning electron microscope (SEM). The diameter of each of the plurality of pores was measured from the image obtained using the image analysis software, and the average diameter (D _a ) was calculated. The average diameter was defined as an average value obtained by dividing the sum of the plurality of pore diameters in 1 mm 2 of the polished surface by the number of pores.

The pores include closed pores disposed inside the polishing pad and open pores disposed on the polishing surface of the polishing pad.

Specifically, in the open pores, the pore inlet is exposed on the polishing surface.

Here, the diameter of the inlet of the open pore may mean a diameter of a circle having the same planar area as that of the inlet of the open pore. In addition, the average diameter of the inlets of the open pores may be calculated by number-averaging the diameters of the plurality of open pore inlets present on the polishing surface.

The total number of pores per unit area (mm ^{2) of the polishing pad may be 700 or more.} More specifically, the total number of pores per unit area (mm ^{2) of the polishing pad may be 750 or more.} More specifically, the total number of pores per unit area (mm ^{2) of the polishing pad may be 800 or more.} More specifically, the total number of pores per unit area (mm ² ) of the polishing pad may be 900 or more, but is not limited thereto. In addition, the ^{total number of pores per unit area (mm 2} ) of the polishing pad may be 2500 or less, specifically 2200 or less, 1500 or less, or 1200 or less, but is not limited thereto. Therefore, the total number of pores per unit area (mm ² ) of the polishing pad may be 700 to 2500, for example, 750 to 2200, 800 to 1500, or 800 to 1200, It is not limited thereto.

Specifically, the polishing pad may have an elastic modulus of 60 kgf/cm ^{2 or} more. More specifically, the elastic modulus of the polishing pad may be 100 kgf/cm ^{2 or} more, but is not limited thereto. The upper limit of the elastic modulus of the polishing pad may be 150 kgf/cm ² , but is not limited thereto.

In addition, the polishing pad according to the embodiment may have excellent polishing performance and excellent basic physical properties as a polishing pad, such as withstand voltage, specific gravity, surface hardness, tensile strength, and elongation.

Physical properties such as specific gravity and hardness of the polishing pad can be controlled through the molecular structure of the urethane-based prepolymer polymerized by the reaction of isocyanate and polyol.

Specifically, the polishing pad may have a surface hardness of 45 Shore D to 65 Shore D at 25°C. More specifically, the polishing pad may have a hardness of 50 Shore D to 65 Shore D, but is not limited thereto.

Specifically, the polishing pad may have a specific gravity of 0.6 g/cm 3 to 0.9 g/cm 3. More specifically, the polishing pad may have a specific gravity of 0.7 g/cm 3 to 0.85 g/cm 3, but is not limited thereto.

Specifically, the polishing pad may have a tensile strength of 10 N/mm2 to 100 N/mm2. More specifically, the polishing pad may have a tensile strength of 15 N/mm2 to 70 N/mm2. More specifically, the polishing pad may have a tensile strength of 20 N/mm2 to 70 N/mm2, but is not limited thereto.

Specifically, the polishing pad may have an elongation of 30% to 300%. More specifically, the polishing pad may have an elongation of 50% to 200%.

The polishing pad has a dielectric strength of 14 kV to 23 kV, a thickness of 1.5 mm to 2.5 mm, a specific gravity of 0.7 g/cm 3 to 0.9 g/cm 3, and a surface hardness of 50 shore D to 65 shore D at 25°C. , The tensile strength may be 15 N/mm2 to 25 N/mm2, and the elongation may be 80% to 250%, but is not limited thereto.

The polishing pad may have a thickness of 1 mm to 5 mm. Specifically, the polishing pad is 1 mm to 3 mm, 1 mm to 2.5 mm, 1.5 mm to 5 mm, 1.5 mm to 3 mm, 1.5 mm to 2.5 mm, 1.8 mm to 5 mm, 1.8 mm to 3 mm, or It may have a thickness of 1.8 mm to 2.5 mm. When the thickness of the polishing pad is within the above range, basic physical properties as a polishing pad can be sufficiently exhibited.

Meanwhile, the polishing pad may have a groove for mechanical polishing on its surface. The groove may have an appropriate depth, width and spacing for mechanical polishing, and is not particularly limited.

The polishing pad according to the embodiment may simultaneously exhibit the physical properties of the polishing pad described above.

[Semiconductor device manufacturing method]

A method of manufacturing a semiconductor device according to an embodiment of the present invention includes: providing a polishing pad including a polishing layer; And polishing the polishing target while relatively rotating so that the polishing target surface of the polishing layer abuts against the polishing surface of the polishing layer.

Specifically, a method of manufacturing a semiconductor device according to an embodiment of the present invention includes the steps of mounting a polishing pad including a polishing layer on a surface plate; And polishing the surface of the wafer by rotating relative to each other so that the polishing surface of the polishing layer and the surface of the wafer contact each other, wherein the polishing pad is calcined on a polishing pad using a silicon oxide wafer (PETEOS wafer). While spraying the ceria slurry at a rate of 200 cc/min, 25 dummy wafers were polished for 60 seconds each, and two monitoring wafers were polished for 60 seconds each, and then the polishing pad after polishing was applied to the optical surface. When measured with a roughness meter, Equation 11 may be satisfied in the area material ratio curve based on the ISO 25178-2 standard.

A method of manufacturing a semiconductor device according to another embodiment of the present invention includes the steps of mounting a polishing pad including a polishing layer on a platen; And polishing the surface of the wafer by rotating relative to each other so that the polishing surface of the polishing layer and the surface of the wafer contact each other, wherein the polishing pad is calcined on a polishing pad using a silicon oxide wafer (PETEOS wafer). While spraying the ceria slurry at a rate of 200 cc/min, 25 dummy wafers were polished for 60 seconds each, and two monitoring wafers were polished for 60 seconds each, and then the polishing pad after polishing was applied to the optical surface. When measured with a roughness meter, the above equations 1 and 2 may be satisfied in the area material ratio curve based on the ISO 25178-2 standard.

A method of manufacturing a semiconductor device according to another embodiment of the present invention includes the steps of mounting a polishing pad including a polishing layer on a surface plate; And polishing the surface of the wafer by rotating relative to each other so that the polishing surface of the polishing layer and the surface of the wafer contact each other, wherein the polishing pad is calcined on a polishing pad using a silicon oxide wafer (PETEOS wafer). While spraying the ceria slurry at a rate of 200 cc/min, 25 dummy wafers were polished for 60 seconds, and two monitoring wafers were polished for 60 seconds, and then the polishing pad after polishing was applied to the optical surface. When measured with a roughness meter, Equation 4 can be satisfied in the area material ratio curve based on the ISO 25178-2 standard.

A method of manufacturing a semiconductor device according to another embodiment of the present invention includes the steps of mounting a polishing pad including a polishing layer on a surface plate; And polishing the surface of the wafer by rotating relative to each other so that the polishing surface of the polishing layer and the surface of the wafer contact each other, wherein the polishing pad is calcined on a polishing pad using a silicon oxide wafer (PETEOS wafer). While spraying the ceria slurry at a rate of 200 cc/min, 25 dummy wafers were polished for 60 seconds each, and two monitoring wafers were polished for 60 seconds each, and then the polishing pad after polishing was applied to the optical surface. When measured with a roughness meter, the above equations 5 and 6 may be satisfied in the area material ratio curve based on the ISO 25178-2 standard.

Specifically, after the polishing pad according to the embodiment is mounted on a surface, a semiconductor substrate is disposed on the polishing pad. In this case, the semiconductor substrate may be a wafer, and the surface of the wafer is in direct contact with the polishing surface of the polishing pad. For polishing, a polishing slurry may be sprayed on the polishing pad through a nozzle. The flow rate of the polishing slurry supplied through the nozzle may be selected according to the purpose within the range of about 10 cm 3 /min to about 1,000 cm 3 /min, for example, it may be about 50 cm 3 /min to about 500 cm 3 /min. , But is not limited thereto.

Thereafter, the wafer and the polishing pad may rotate relative to each other, so that the surface of the wafer may be polished. In this case, the rotation direction of the wafer and the rotation direction of the polishing pad may be the same or opposite. The rotational speed of the wafer and the polishing pad may be selected according to the purpose in the range of about 10 rpm to about 500 rpm, for example, may be about 30 rpm to about 200 rpm, but is not limited thereto.

The wafer may be pressed and brought into contact with the polishing surface of the polishing pad with a predetermined load while mounted on the polishing head, and then the surface thereof may be polished. The load applied to the polishing surface of the polishing pad on the surface of the wafer by the polishing head may be selected according to the purpose in the range of about 1 gf/cm 2 to about 1,000 gf/cm 2, for example, about 10 gf/cm 2 It may be from ㎠ to about 800 gf/cm2, but is not limited thereto.

In one embodiment, the method of manufacturing the semiconductor device further comprises processing the polishing surface of the polishing pad through a conditioner at the same time as polishing the wafer in order to maintain the polishing surface of the polishing pad in a state suitable for polishing. Can include.

According to the embodiment, when the polishing pad is measured with an optical surface roughness meter after polishing, by controlling the surface roughness volume parameter and the surface roughness height parameter in a specific range in the area material ratio curve based on ISO 25178-2 standard, It is possible to provide a polishing pad capable of improving the polishing rate and reducing residues, surface scratches, and chatter marks appearing on the surface of a wafer, and using this, it is possible to efficiently manufacture a semiconductor device of excellent quality.

Hereinafter, the present invention will be described in more detail by the following examples. However, the following examples are for illustrative purposes only, and the scope of the present invention is not limited thereto.

Example 1. Preparation of polishing pad

(1) Preparation of urethane-based prepolymer

Polytetramethylene ether glycol (Korea PTG) as a polyol and toluene diisocyanate (BASF) as an isocyanate compound were added to a four-necked flask, and the inside of the reactor was introduced with nitrogen (N ₂ ) as an inert gas. It was charged and reacted at 75° C. for 2 hours while stirring to prepare a urethane-based prepolymer. At this time, the NCO% was adjusted to 9.1%.

(2) Manufacturing of polishing pad

A casting apparatus having a tank and an input line for supplying raw materials such as a urethane-based prepolymer, a curing agent, and a foaming agent, respectively, was prepared. As a urethane-based prepolymer prepared above and a curing agent, MOCA (4,4'-Methylne bis(2-chloroaniline) (Sigma-aldrich)) was prepared. The solid foaming agent was prepared by purifying microcapsules (Akzonobel) in which the average particle diameter of the solid foaming agent was adjusted using a solid foaming agent purification system. The solid foaming agent classification and purification apparatus described above was used as the solid foaming agent purification system (see FIGS. 3 to 5).

In a casting machine equipped with the prepared urethane-based polymer, curing agent, inert gas injection line, and solid foaming agent injection line, the urethane-based polypolymer synthesized with the NCO% 9.1% was filled in the urethane-based polypolymer tank and the triethylene diamine was added to the curing agent tank At the same time, the solid foaming agent was injected in 2 parts by weight based on 100 parts by weight of the raw material mixture, and the rotation speed of the mixing head was adjusted to 3000 rpm, followed by stirring. The mixed mixture was discharged at a rate of 10 kg per minute, injected into a mold having an opening of 1000 mm in width and length and 25 cm in height, and solidified through a thermosetting reaction to obtain a molded body.

After that, the solid material of the molded body was sliced to form a sheet. Thereafter, the surface was cut to make the surface roughness of the polishing pad as shown in Table 3 below before polishing. The cut sheet was subjected to a grooving process to obtain one sheet (polished layer) having a thickness of 2 mm. The finished sheet was laminated with the sub pad using an adhesive to finally obtain a polishing pad.

(3) Polishing process

The polishing pad was subjected to a CMP process using the AP-300 model of CTS. Detailed conditions of the CMP process are shown in Table 1 below. After drying the polishing pad on which the CMP process was completed, the surface roughness of the polishing pad was measured using a Contour GT model manufactured by Bruker. The detailed conditions for measuring the surface roughness are shown in Table 2, and the embossed portion of the groove at a point ½ based on the radius of the polishing pad was measured. The measurement was carried out a total of 5 times per polishing pad, and an average value was obtained. After polishing, the surface roughness volume parameter and the surface roughness height parameter of the polishing pad were obtained as shown in Tables 3 and 4, respectively.

Examples 2 to 5

The same method as in Example 1, except that the surface roughness volume parameter and the surface roughness height parameter of the polishing pad before and after polishing were changed as shown in Tables 3 and 4 below by changing the surface processing conditions of the polishing pad to be manufactured. To obtain a polishing pad.

Comparative Example 1

By controlling the rotation speed of the mixing head and not performing the purification process by the solid foaming agent classification and purification device, the surface roughness volume parameter and the surface roughness height parameter of the polishing pad before and after polishing are determined as shown in Tables 3 and 4 below. Except for the adjustment, it was carried out in the same manner as in Example 1 to obtain a polishing pad.

Comparative Examples 2 and 3

The surface roughness volume parameter and surface roughness height parameter of the polishing pad before and after polishing, as shown in Tables 3 and 4 below, by changing the surface processing conditions of the manufactured polishing pad without performing the purification process by the solid foaming agent classification and purification device. A polishing pad was obtained in the same manner as in Example 1, except that the parameters were adjusted.

Table 1 below summarizes the detailed conditions of the CMP process.

Table 2 below summarizes the conditions for measuring the surface roughness of the polishing pad.

Tables 3 and 4 below summarize the results of measuring the surface roughness of the polishing pad before and after polishing in Examples and Comparative Examples.

Test Example 1: removal rate

The initial polishing rate immediately after manufacturing the polishing pad was measured as follows.

Silicon oxide was deposited on a silicon wafer having a diameter of 300 mm by a chemical vapor deposition (CVD) process. A polishing pad was attached to the CMP equipment, and the silicon oxide layer of the silicon wafer was installed to face the polishing surface of the polishing pad. Thereafter, the polishing load was adjusted to be 4.0 psi, while the polishing pad was rotated at 150 rpm, the calcined ceria slurry was added on the polishing pad at a rate of 250 ml/min, while the platen was rotated at 150 rpm for 60 seconds to polish the silicon oxide film. . After polishing, the silicon wafer was removed from the carrier, mounted on a spin dryer, washed with purified water (DIW), and dried with nitrogen (N) for 15 seconds. The dried silicon wafer was measured for change in film thickness before and after polishing using an optical interference type thickness measuring device (manufacturer: Kyence, model name: SI-F80R). Thereafter, the polishing rate was calculated using Equation 12 below.

[Equation 12]

Polishing rate (Å/min) = polishing thickness of silicon wafer (Å) / polishing time (minute)

Test Example 2: Measurement of residue, number of scratches and chatter mark

After performing the polishing process described in Examples and Comparative Examples using a polishing pad, residues appearing on the surface of the wafer (monitoring wafer) after polishing using defect inspection equipment (AIT XP+, KLA Tencor) , Scratch and chatter mark were measured (condition: threshold 150, die filter threshold 280).

The residue substantially means that amorphous foreign matter adheres to the wafer surface, and, for example, means a defect in the shape as shown in FIG. 6.

The scratch refers to a substantially continuous linear scratch, and for example, refers to a defect in the shape as shown in FIG. 7.

Meanwhile, the chatter mark refers to a substantially discontinuous linear scratch, and, for example, refers to a defect in the shape as shown in FIG. 8.

The results are shown in Table 5 below.

As can be seen in Table 5 above, the polishing pads of Examples 1 to 5, in which the surface roughness height parameter and the surface roughness volume parameter of the polishing pad after polishing were adjusted within a specific range, have excellent polishing rates, and residuals appearing on the wafer surface. It can be seen that the number of water, surface scratches and chatter marks is significantly lower than that of the case of using the polishing pads of Comparative Examples 1 to 3.

Specifically, the polishing rate of Examples 1 to 3 was generally excellent, from 2919 Å/min to 2998 Å/min, whereas the polishing rate of the polishing pad of Comparative Example 2 was 4153 Å/min, and voids capable of supporting the slurry. The initial polishing rate was excessively high due to an increase in the ratio of the friction area to the contrast. Accordingly, the polishing pad of Comparative Example 2 is expected to further increase the polishing rate due to pad glazing. On the other hand, the polishing rate of the polishing pad of Comparative Example 1 was 2081 Å/min, which significantly decreased the polishing rate.

On the other hand, in the case of the polishing pads of Examples 4 and 5, the polishing rate was slightly lowered or slightly increased compared to the polishing pads of Examples 1 to 3, but the number of residues, surface scratches and chatter marks appeared on the wafer surface It was similar to the case of using the polishing pads of Examples 1 to 3, and significantly decreased compared to the case of using the polishing pads of Comparative Examples 1 to 3.

Specifically, looking at the residues appearing on the wafer surface, when the polishing pads of Examples 1 to 5 were used, there were 62 to 100 residues, whereas when the polishing pads of Comparative Examples 1 to 3 were used, the number of residues exceeded 200. Thus, compared to the case of using the polishing pads of Examples 1 to 5, it was shown to be significantly increased by more than two times.

In addition, looking at scratches, when the polishing pads of Examples 1 to 5 were used, the scratches were 125 to 161, whereas when the polishing pads of Comparative Examples 1 to 3 were used, the number of scratches was 575 or more, and the polishing of Examples 1 to 5 Compared to the case of using the pad, it was significantly increased by more than 3 times.

In addition, looking at chatter marks, when the polishing pads of Examples 1 to 5 were used, the number of chatter marks was 3.5 or less, whereas when the polishing pads of Comparative Examples 1 to 3 were used, the chatter marks exceeded 13, and Examples 1 to 5 Compared to the polishing pad of 5, it was significantly increased more than 4 times.

Therefore, it can be seen that it is advantageous in maintaining a constant polishing performance that the surface roughness during or after the polishing process is kept constant rather than the surface roughness before polishing.

110: head 120: semiconductor substrate (wafer)
130: platen 140: slurry
150: qigong
10a, 10c: piping 30a, 30b: filter part
31: filter housing 32: filter cover
33: filter member 311: filter space
312: filter inlet 321: filter outlet
331: mounting portion 332: magnet
50: classification unit 51: classification housing
53: vortex generating member 54: discharge filter
56: vibration generating unit
511: classification space 511a: central axis
512: classification inlet hole 513: first microsphere discharge hole
514: second microsphere discharge hole
515: gas supply hole 516: gas discharge hole
A: Flow indication of flowing gas
B: Display of the flow of solid foam
C: Vibrating arrow.

Claims (11)

Using a silicon oxide wafer (PETEOS wafer), while spraying the calcined ceria slurry on the polishing pad at a rate of 200 cc/min, 25 dummy wafers were polished for 60 seconds each, and two monitoring wafers were each After polishing every 60 seconds,
When the polishing pad after polishing is measured with an optical surface roughness meter, a polishing pad that satisfies the following equation 11 in an area material ratio curve based on ISO 25178-2 standard:
[Equation 11]
0.5≤(Spk + Svk)/Sk≤3.5
In Equation 11 above,
Spk is a reduced peak height,
The Svk is the reduced valley depth,
Sk is the core roughness depth.
The method of claim 1,
A polishing pad in which a pre break in process is performed for 10 to 20 minutes before polishing the dummy wafer to condition the polishing layer of the polishing pad.
The method of claim 1,
The polishing pad,
The Spk is 2 or more to 10 or less,
The Svk is greater than 11 and less than or equal to 22,
The Sk is 5 or more to 40 or less, and
The total sum of the Spk and the Svk satisfies any one or more selected from more than 13 to 32 or less.
The method of claim 1,
The polishing pad after the polishing satisfies any one or more selected from Equations 5 to 10 below:
[Equation 5]
Spk/Svk<1.2
[Equation 6]
0.1≤Spk/Sk≤1.1
[Equation 7]
0.2<Svk/Sk≤2.5
[Equation 8]
0.3<Spk/Svk + Svk/Sk≤3.6
[Equation 9]
0.3<Spk/Sk + Svk/Sk≤3.6
[Equation 10]
0.45≤Spk/Sk + Svk/Sk + Spk/Svk≤4.7
In the above formulas 5 to 10,
The Spk, Svk and Sk are as defined in claim 1.
The method of claim 4,
The absolute value of the difference between Svk/Sk before and after polishing of the polishing pad is 0.1 to 1.5,
A polishing pad, wherein an absolute value of a difference between Spk/Sk before and after polishing of the polishing pad is 0 to 0.6.
The method of claim 1,
The polishing pad includes a plurality of pores having an average diameter of 5 μm to 200 μm,
The polishing pad has a polishing rate of 2600 Å/min to 3300 Å/min for the oxide film;
100 or less of the number of surface residues on the monitoring wafer;
200 or less of the number of scratches on the surface of the monitoring wafer; And
A polishing pad that satisfies at least one characteristic selected from among characteristics of the number of chatter marks of the monitoring wafer being 5 or less.
Preparing a raw material mixture by mixing a urethane-based prepolymer, a curing agent, and a foaming agent; And
Injecting the raw material mixture into a mold and curing to obtain a polishing pad,
Using a silicon oxide wafer (PETEOS wafer), while spraying the calcined ceria slurry on the polishing pad at a rate of 200 cc/min, 25 dummy wafers were polished for 60 seconds each, and two monitoring wafers were each After polishing every 60 seconds,
When the polishing pad after polishing is measured with an optical surface roughness meter, the method of manufacturing a polishing pad satisfies the following equation 11 in the area material ratio curve based on the ISO 25178-2 standard:
[Equation 11]
0.5≤(Spk + Svk)/Sk≤3.5
In Equation 11 above,
Spk is a reduced peak height,
The Svk is the reduced valley depth,
Sk is the core roughness depth.
The method of claim 7,
The foaming agent includes a solid foaming agent, a gaseous foaming agent, or a mixed foaming agent thereof,
The solid foaming agent is a solid foaming agent purified by a solid foaming agent purification system, a method of manufacturing a polishing pad.
The method of claim 7,
The mixing is carried out at a speed of 500 rpm to 10000 rpm using a mixing head, a method of manufacturing a polishing pad.
The method of claim 8,
The method of manufacturing a polishing pad, wherein the purified solid foaming agent has an average particle diameter (D50) of 5 μm to 200 μm.
Mounting a polishing pad including a polishing layer on a surface; And
Polishing the surface of the wafer by rotating relative to each other so that the polishing surface of the polishing layer and the surface of the wafer come into contact with each other; and
The polishing pad uses a silicon oxide wafer (PETEOS wafer) to polish 25 dummy wafers for 60 seconds each while spraying the calcined ceria slurry on the polishing pad at a rate of 200 cc/min. ) After polishing the wafer for 60 seconds each, when the polishing pad after polishing is measured with an optical surface roughness meter, the method for manufacturing a semiconductor device satisfies the following Equation 11 in the area material ratio curve based on the ISO 25178-2 standard:
[Equation 11]
0.5≤(Spk + Svk)/Sk≤3.5
In Equation 11 above,
Spk is a reduced peak height,
The Svk is the reduced valley depth,
Sk is the core roughness depth.

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