KR20120128540A - Cmp pad conditioner - Google Patents

Abstract

PURPOSE: A CMP pad conditioner is provided to increase a lifetime thereof by controlling pressure applied to a cutting tip to change the abrasion speed of the cutting tip. CONSTITUTION: Plural cutting tips are protruded on the surface of a substrate. The plural cutting tips are separated from each other. The upper surface of the cutting tip is a plane which is parallel to the substrate surface. The height of the cutting tip is 100μm or less. The average pressure of one cutting tip is 0.001 lbf/cm2/ ea to 0.2 lbf/cm2/ea. [Reference numerals] (AA) Pad abrasion degree; (BB) Pressure per tip

Description

CMP PAD CONDITIONER {CMP PAD CONDITIONER}

The present invention relates to a conditioner for a CMP pad used in a chemical mechanical polishing (CMP) process, which is a part of a semiconductor device fabrication process. More specifically, a cutting tip structure in which the amount of wear of the polishing pad does not change significantly even when the slurry type and the conditioner pressure change. A CMP pad conditioner having a.

CMP technology used in semiconductor devices is used to planarize thin films such as insulating films and metal films formed on semiconductor wafers.

In the planarization process using CMP technology, a polishing pad is attached to a rotating platen, and a carrier is held while holding a wafer whose carrier is a polishing object and supplying a slurry onto the pad. It is a processing method in which the surface plate and the carrier are moved relative to each other and polished while pressure is applied to the carrier.

Thus, in CMP technology for planarization, the uniformity of removal rate across the workpiece surface, such as wafers (polishing uniformity) is an important property. Among various factors for improving polishing uniformity, the surface state of the polishing pad may also be an important quantitative factor.

The desired surface condition of the polishing pad is achieved through conditioning of the polishing pad, which is performed by cutting the surface of the deformed pad with a conditioner to restore the worn or clogged pores of the polishing pad and the flattening of the broken polishing pad. Can be.

Here, the conditioning causes the pad conditioner to have a diamond-like grinder in contact with the polishing pad to scrape or rough the surface of the polishing pad, such that the surface state of the new polishing pad is optimized to an initial state with good retention of slurry, or In use, the slurry holding ability of the polishing pad is restored to maintain the polishing ability of the polishing pad.

On the other hand, the slurry used in the CMP process can be largely divided into oxide slurry, tungsten (W) slurry, kappa (Cu) slurry. Each slurry is different in the type, shape, size, additive type and content of the abrasive particles, the impact on the pad during the CMP process. In addition, even if the material of the pad and the pressure applied to the CMP pad conditioner in contact with the pad are different, the influence on the pad during the CMP process is different.

Therefore, even if the same CMP pad conditioner is used, the pad wear is different depending on the type of slurry, the material of the pad, and the pressure change. Therefore, as long as the conditioner suitable for each slurry, pad, and pressure change used in conditioning is used, the appropriate CMP The challenge of deriving pad conditioners is the difficulty of evaluating products with numerous specifications.

In particular, among the conventionally known CMP pad conditioner, the first diamond electrodeposition pad conditioner has the following problems. That is, it is difficult to control the protrusion height of the diamond because the diamond abrasive grains used are manufactured in various shapes such as Cube, Octahedral, Cube-octahedral, and diamonds are attached without directivity even when a certain shape diamond is used. As a result, it is difficult to calculate the area of diamond in contact with the pad because the area of diamond in contact with the pad cannot be equally controlled. This means that the pressure applied to each of the diamonds in contact with the pads in the conditioner cannot be predicted, which means that performance is difficult to predict.

In addition, as disclosed in Korean Patent No. 10-0387954, a CVD pad conditioner having a structure in which a plurality of polygonal cones protruding at a uniform height upwards is formed on a surface of a substrate, and a diamond layer is deposited by CVD on the surface thereof. Although the CVD pad conditioner having the above structure can be used at a constant pressure, the pad wear rate is changed according to the change in the conditioning pressure even though the polishing pad is not properly conditioned when the pad wear rate (PWR) is not stable. In other words, the extent to which the PWR increases or decreases is very large. As a result, in the case of the conventional CVD conditioner disclosed in the patent, there is a problem that a large change in pad wear amount is caused by a load change added to the disk, and a disk pressure range that can be used according to the slurry change is very large.

The present inventors have completed the present invention as a result of research efforts to solve the above disadvantages and problems of the prior art.

Accordingly, an object of the present invention is to provide a CMP pad conditioner having a small variation in pad wear caused by any one or more of slurry type, pad material and pressure change because it has an optimized structure to be used stably under any conditioning operation conditions. will be.

It is another object of the present invention to design a CMP pad conditioner with a structure capable of predicting pad abrasion with only a few experiments without hundreds of experiments, thereby efficiently manufacturing a CMP pad conditioner, thereby providing a CMP pad conditioner having excellent productivity and product quality. It is.

It is still another object of the present invention to provide a CMP pad conditioner having an extended product life and a constant pad roughness than a conventional CMP pad conditioner.

Another object of the present invention is to present the size and number of tips that can maintain the pad wear amount at a constant value in the range of applying a constant pressure to the cutting tip, to maximize the service life of the conditioner by controlling the wear rate of the cutting tip In addition to providing a CMP pad conditioner that can adjust the life of the conditioner.

The objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, the present invention is a substrate; And a plurality of cutting tips protruding above the surface of the substrate and spaced apart from each other, wherein the cutting tips have a flat top surface parallel to the surface of the substrate, the cutting tips 1 being conditioned. It provides a CMP pad conditioner, characterized in that it has a structure that the average pressure received per piece is 0.001 lbf / cm 2 / ea to 0.2 lbf / cm 2 / ea.

The present invention has the following excellent effects.

First, according to the CMP pad conditioner of the present invention has a structure that is optimized to be used stably under any conditioning operation conditions, the amount of change in pad wear caused by any one or more of slurry type, pad material and pressure change is small.

In addition, according to the CMP pad conditioner of the present invention, the CMP pad conditioner can be designed in a structure capable of predicting the pad wear amount by only a few experiments without hundreds of experiments, so that the CMP pad conditioner can be efficiently manufactured, thereby providing excellent productivity and product quality. .

In addition, according to the CMP pad conditioner of the present invention, it is possible to prolong the life of the product and to maintain a constant pad roughness than the conventional CMP pad conditioner.

According to the present invention, it is possible to change the surface roughness and debris size of the required pad according to the area of the cutting tip while keeping the pad polishing amount constant.

In addition, it is possible to calculate the average pressure of the working tip required to maintain a constant amount of pad wear per slurry, it is possible to design the required number of tips if the tip area is set.

In addition, the average pressure applied to the cutting tip is in the range of 0.001 to 0.2 lbf / cm2 / ea without changing the amount of pad wear, it is possible to change the wear rate of the cutting tip by adjusting the pressure applied per cutting tip to maintain a constant amount of pad wear There is an effect of increasing the use time of the conditioner when holding.

1 to 3 illustrate PWR measurement results according to the slurry types of CMP pad conditioners 1 to 11 and Comparative Conditioners 1 and 2 prepared according to Comparative Examples 1 and 2 according to Examples 1 to 11 of the present invention. One Graph,
Figure 4 is a graph showing the amount of pad wear and pad roughness measurement results according to the conditioning time of the CMP pad conditioner 4 prepared according to Example 4 of the present invention.

Although the terms used in the present invention have been selected as general terms that are widely used at present, there are some terms selected arbitrarily by the applicant in a specific case. In this case, the meaning described or used in the detailed description part of the invention The meaning must be grasped.

Hereinafter, with reference to the preferred embodiment shown in the accompanying drawings will be described in detail the technical configuration of the present invention.

However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Like reference numerals used to describe the present invention throughout the specification denote like elements.

The technical feature of the present invention is that in a CMP pad conditioner having a structure including a plurality of cutting tips protruding above and spaced apart from the substrate and the surface of the substrate, when the top surface of the cutting tip is formed parallel to the substrate surface, the conditioning operation The average pressure per cutting tip can be calculated and experimentally determine the optimum average pressure range with a small change in pad wear caused by any one or more of slurry type, pad material or pressure change, The present invention provides a CMP pad conditioner having a structure optimized for stable use and a method of manufacturing the same.

That is, if the pressure received per cutting tip formed in the CMP pad conditioner has a structure of 0.001 lbf / cm 2 / ea to 0.2 lbf / cm 2 / ea, even if any one or more of the slurry type, the pad material, and the pressure change vary considerably. This is because experimentally confirmed that the range of PWR change can be significantly reduced.

Accordingly, the CMP pad conditioner of the present invention comprises a substrate; And a plurality of cutting tips protruding above the surface of the substrate and spaced apart from each other, wherein the cutting tips have a flat top surface parallel to the surface of the substrate, the cutting tips 1 being conditioned. The average pressure received per piece is 0.001 lbf / cm 2 / ea to 0.2 lbf / cm 2 / ea.

Here, once the average pressure received per one CMP pad conditioner cutting tip is determined, the cutting tip should be formed so that the average pressure received by one cutting tip can be maintained substantially constant even if the cutting tip wears during the conditioning operation. As a result, the upper surface of the cutting tip is formed such that the surface formed by connecting the outer periphery of the cross section and the outer periphery of the top surface at a point of 5 μm to 50 μm downward from the top surface of the cutting tip forms 87 ° to 93 ° with respect to the top surface. It is preferable to be.

Experimentally, during the life cycle of a CMP pad conditioner, the life of the CMP pad conditioner when the rate of change of the cutting tip top surface area is within 10% after the end of the CMP pad conditioner life compared to the initial value before using the CMP pad conditioner. Preferred results were obtained in terms of extension and minimization of PWR variation.

In the present invention, the top surface area of one cutting tip included in the completed CMP pad conditioner is preferably 25 to 10000 μm ² , and the total height of the cutting tip may be 100 μm or less.

The CMP pad conditioner with the structure of the present invention was kept constant 2 to 10 times compared to the conditioner using conventional diamond particles regardless of the type of slurry used for the PWR during the conditioning operation, and the pad roughness during the conditioning operation was also 2 It was maintained at 10 to 10 ㎛ exhibited excellent product properties.

In addition, the CMP pad conditioner manufacturing method of the present invention comprises the steps of determining the average pressure applied per cutting tip in contact with the pad during the conditioning operation in the range of 0.001 lbf / cm 2 / ea to 0.2 lbf / cm 2 / ea; Determining the size and number of the plurality of cutting tips to be formed to protrude upward on the surface of the substrate according to the determined average pressure; And forming a cutting tip on the substrate in the size and number of the determined cutting tips.

Here, the size and number of the plurality of cutting tips to be formed to protrude upward on the surface of the substrate is determined by the following formula (1).

[Equation 1]

Pe = (D / As) ÷ T

Pe: Average pressure per cutting tip

D: Load (total pressure under CMP pad conditioner)

As: Sum of the top surface area of all cutting tips

T: number of cutting tips

The size of the cutting tip is determined by the area and height of the top of the cutting tip. The height does not affect the average pressure of the cutting tip, so it may be a known height of a commonly known CMP pad conditioner. The overall height may be 100 μm or less.

In addition, the present invention can select the size of the cutting tip to change the roughness of the pad and the size of the debris of the pad while maintaining a constant amount of wear (μm / hr) of the pad. Experimentally, the top surface area of one cutting tip is preferably 25 to 10000 μm ² . If the top surface area is less than 25㎛ ² , the load applied by one cutting tip will increase, and the tip may break during use, resulting in wafer scratches.If it exceeds 10000㎛ ² , it will be larger than the pad pore size, preventing padding and preventing pad pores. This is because conditioning cannot occur.

On the other hand, in the present invention, a variable for polishing a certain amount of the pad in a conditioner having a constant height and shape of the cutting tip may be expressed as shown in Equation 2 below.

[Equation 2]

Pw = Pe × T

Pw: Pad wear

Pe: average pressure applied per tip

T: number of cutting tips

Therefore, the number of the segment required to indicate a certain amount of wear pad is a small area 25 ~ 625㎛ calculated based on [Equation 2] in the average pressure of 0.001 ~ 0.2lbf / ㎠ / ea range ² it indicates the top side segment is 2680-190000. In the same way, when the cutting tip area is 625 ~ 2500㎛ ² , 1340 ~ 38000 pieces, and when the 2500 ~ 10000㎛ ² tip number is composed of 670 ~ 190000 can obtain a certain amount of pad wear.

That is, since the surface roughness and debris size when the pad is polished vary according to the area of the cutting tip, the area of the cutting tip can be changed according to the conditions required for each CMP process. This is because the number of cutting tips can be determined.

As such, when the size and number of cutting tips to be formed on the substrate are determined, the substrate and protrusions having any one of cylinder, polygon, cone, and pyramid shapes are integrally or individually formed using materials of a known CMP conditioner. Next, it is preferable to form diamond-cutting portions by depositing diamond on the substrate and the surface of the protrusion by CVD.

Example 1

The average pressure received per cutting tip in contact with the pad during conditioning is 0.001, and the size and number of cutting tips are determined using [Equation 1] Pe = (D / As) ÷ T described above at 9 pounds of load. CMP pad conditioner 1 was prepared as follows.

First, a plurality of protrusions each having a square pyramid shape having a diameter of 50 μm and a height of 70 μm and a height of 70 μm on the surface of the disk-shaped substrate and the substrate having a diameter of 4 inches were integrally formed with 19000ea.

Thereafter, diamond is deposited on the surface of the formed substrate and the protrusion by CVD to form a cutting portion made of a diamond layer. Particularly, the cutting portion formed on the upper portion of the protrusion is formed from the top surface of the cutting tip formed of the protrusion and the cutting portion. The surface formed by connecting the outer circumference of the cross section and the upper circumference of the point of 10 μm downward was formed to form an almost 90 ° with respect to the top surface to form an upper portion of the cutting tip.

Example 2

The average pressure received per cutting tip in contact with the pad during conditioning was determined to be 0.03, and the surface formed by connecting the outer periphery of the cross section and the outer periphery of the top of the cutting tip at an angle of 10 μm downward from the top surface, CMP pad conditioner 2 was prepared under the same conditions and methods as in Example 1 except that the angle formed with respect to the top surface was almost 89 °.

The upper surface of the cutting tips formed on the manufactured CMP pad conditioner 2 was 50 μm in width and length, respectively, and the total number of cutting tips was 3450ea.

Example 3

The average pressure per cutting tip contacted with the pad during the conditioning operation was determined to be 0.05, and the surface formed by connecting the outer periphery of the cross section and the outer periphery of the top of the cutting tip at an angle of 10 μm downward from the top surface CMP pad conditioner 3 was prepared under the same conditions and methods as in Example 1 except that the angle formed with respect to the top surface was almost 91 °.

The upper surface of the cutting tips formed on the manufactured CMP pad conditioner 3 was 50 µm in width and length, respectively, and the total number of cutting tips was 2700ea.

Example 4

CMP pad conditioner 4 was prepared under the same conditions and methods as in Example 1 except that the average pressure received per cutting tip in contact with the pad during the conditioning operation was determined to be 0.07.

The upper surface of the cutting tips formed on the manufactured CMP pad conditioner 4 was 50 μm in width and length, respectively, and the total number of cutting tips was 2275ea.

Example 5

The average pressure received per cutting tip in contact with the pad during the conditioning operation was determined to be 0.09, and the surface formed by connecting the outer periphery of the cross section and the outer periphery of the top of the cutting tip at an angle of 10 μm downward from the top surface. CMP pad conditioner 5 was prepared under the same conditions and methods as in Example 1 except that the angle formed with respect to the top surface was almost 89 °.

The upper surface of the cutting tips formed on the manufactured CMP pad conditioner 5 was 50 μm in width and length, respectively, and the total number of cutting tips was 2000ea.

Example 6

The average pressure per cutting tip in contact with the pad during the conditioning operation was determined to be 0.11, and the surface formed by connecting the outer periphery of the cross section and the outer periphery of the top of the cutting tip at an angle of 10 μm downward from the top surface CMP pad conditioner 6 was prepared under the same conditions and methods as in Example 1 except that the angle formed with respect to the top surface was almost 91 °.

The upper surface of the cutting tips formed on the manufactured CMP pad conditioner 6 was 50 µm in width and length, respectively, and the total number of cutting tips was 1800ea.

Example 7

CMP pad conditioner 7 was prepared under the same conditions and methods as in Example 1 except that the average pressure received per cutting tip in contact with the pad during the conditioning operation was determined to be 0.13.

The upper surface of the cutting tips formed on the manufactured CMP pad conditioner 7 was 50 µm in width and length, respectively, and the total number of cutting tips formed was 1670ea.

Example 8

The average pressure per cutting tip in contact with the pad during the conditioning operation was determined to be 0.15, and the surface formed by connecting the outer periphery of the cross section and the outer periphery of the top of the cutting tip at an angle of 10 μm downward from the top surface CMP pad conditioner 8 was prepared under the same conditions and methods as in Example 1 except that the angle formed with respect to the top surface was almost 89 °.

The upper surface of the cutting tips formed on the manufactured CMP pad conditioner 8 was 50 μm in width and length, respectively, and the total number of cutting tips was 1550ea.

Example 9

The average pressure per cutting tip in contact with the pad during the conditioning operation was determined to be 0.165, and the surface formed by connecting the outer periphery of the cross section and the outer periphery of the top of the cutting tip at an angle of 10 μm downward from the top surface CMP pad conditioner 9 was prepared under the same conditions and methods as in Example 1 except that the angle formed with respect to the top surface was almost 91 °.

The upper surface of the cutting tips formed on the manufactured CMP pad conditioner 9 was 50 μm in width and length, respectively, and the total number of cutting tips was 1475ea.

Example 10

A CMP pad conditioner 10 was prepared under the same conditions and methods as in Example 1 except that the average pressure received per cutting tip in contact with the pad during the conditioning operation was determined to be 0.18.

The upper surface of the cutting tips formed on the manufactured CMP pad conditioner 10 was 50 μm in width and length, respectively, and the total number of cutting tips formed was 1415ea.

Example 11

The average pressure per cutting tip in contact with the pad during conditioning was determined to be 0.2, and the surface formed by connecting the outer periphery of the cross section and the outer periphery of the tip at an angle of 10 μm downwardly from the top of the cutting tip CMP pad conditioner 11 was prepared under the same conditions and methods as in Example 1 except that the angle formed with respect to the top surface was almost 89 °.

The upper surface of the cutting tips formed on the manufactured CMP pad conditioner 11 was 50 µm in width and length, respectively, and the total number of cutting tips was 1340ea.

Comparative Example 1

Comparative Example Conditioner 1 was prepared under the same conditions and methods as in Example 1 except that the average pressure received per cutting tip in contact with the pad during the conditioning operation was determined to be 0.0005.

The upper surface of the cutting tips formed on the prepared Comparative Example Conditioner 1 was 50 μm in width and length, respectively, and the total number of cutting tips formed was 26800ea.

Comparative Example 2

Comparative Example Conditioner 2 was prepared under the same conditions and methods as in Example 1 except that the average pressure received per cutting tip in contact with the pad during the conditioning operation was determined to be 0.22.

The upper surface of the cutting tips formed on the prepared Comparative Conditioner 2 was 50 μm in width and length, respectively, and the total number of cutting tips was 1280ea.

Experimental Example 1

Experiments were carried out to measure PWRs according to the slurry of CMP pad conditioners 1-11 and Comparative Conditioners 1 and 2 prepared in Examples 1-11. In other words, during the conditioning operation with a load of 9 pounds using tungsten slurry, the variation in PWR according to the average pressure received per cutting tip formed in the CMP pad conditioner was observed and the results are shown in FIG. 1.

Experimental Example 2

Except that the slurry was used as an oxide slurry, the same experiment as in Experiment 1 was performed, and the results are shown in FIG. 2.

Experimental Example 3

Except that the slurry was used as a kappa slurry, the same experiment as in Experiment 1 was performed, and the results are shown in FIG. 3.

1 to 3 showing the results of Experimental Examples 1 to 3, the average pressure received per cutting tip formed in the CMP pad conditioner is 0.001 lbf / cm 2 / ea to 0.2 lbf / cm 2 / ea even if the type of slurry is different. If it is in the range, it can be seen that the PWR, or the pad wear amount, is located at 100 or less, so that the conditioning operation can be effectively performed. Particularly, when the average pressure is less than 0.001 lbf / cm 2 / ea, it can be seen that the pad wear amount is almost zero, and when it exceeds 0.2 lbf / cm 2 / ea, the pad wear amount is very high, exceeding 100 μm / hr. You can see that it is not applicable to the task.

Therefore, in order to minimize the PWR variation according to the type of slurry, it can be seen that the average pressure received per cutting tip formed in the CMP pad conditioner should be in the range of 0.001 lbf / cm 2 / ea to 0.2 lbf / cm 2 / ea as in the present invention. .

Experimental Example 4

The amount of pad wear and pad roughness according to the conditioning time were measured while performing the conditioning operation for 50 hours on the CMP pad conditioner 4 manufactured in Example 4 under the same conditions as in Experiment 1, and the measurement results are shown in Table 1 and FIG. 4 is shown.

As shown in Table 1 and FIG. 4 showing the results of Experimental Example 4, the pad wear amount and the pad roughness were almost the same as the first time when the pad wear amount and the pad roughness were checked while using the CMP pad conditioner of the present invention for a predetermined time. It can be seen that by maintaining the constant value.

Time (hr) Pad wear amount (㎛ / hr) Pad Roughness (μm) One 21.0 5.4 2 22.0 3 22.0 4 21.3 5 19.8 4.9 6 20.3 7 20.5 8 20.5 9 22.2 10 20.7 5.1 11 22.5 12 22.9 13 23.5 14 22.6 15 23 5.6 16 23.4 17 23.9 18 22.4 19 22.3 20 21.5 5.5 21 22.5 22 21.7 23 20.2 24 22.3 25 21.2 5.1 26 22.4 27 22.9 28 24 29 23.6 50 24.4 5.7

In FIG. 4, only 30 hours were recorded, but as shown in Table 1, even though tungsten slurry has a fast diamond wear, it can be seen that a constant value is maintained even after 50 hours.

In addition, in Table 1 and FIG. 4, only the results of the CMP pad conditioner 4 are shown. However, the CMP pad conditioners 1 to 3 and 5 to 11 also maintain a constant value in almost the same manner as the CMP pad conditioner 4. there was.

The above experimental results show that the CMP pad conditioner of the present invention can provide a structure that is optimized to be used stably under any conditioning conditions because the change in pad wear amount due to slurry type and pressure change is considerably small.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, Various changes and modifications will be possible.

Claims (1)

Board; And a plurality of cutting tips protruding above the substrate surface and spaced apart from each other.
The cutting tip is a plane whose top surface is parallel to the substrate surface,
CMP pad conditioner, characterized in that the structure has an average pressure of 0.001 lbf / ㎠ / ea to 0.2 lbf / ㎠ / ea for each cutting tip in the conditioning operation.

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