KR101413530B1 - Cmp pad conditioner and its manufacturing method - Google Patents

Abstract

A CMP pad conditioner is disclosed. This CMP pad conditioner includes a base material having a main surface. A plurality of projections are formed on a main surface of the base material in a predetermined arrangement, and one or more diamond grains are fixed to the upper portions of the projections.

Description

[0001] CMP PAD CONDITIONER AND ITS MANUFACTURING METHOD [0002]

The present invention relates to a CMP pad conditioner and a method of manufacturing the same, and relates to a CMP pad conditioner including a plurality of protrusions on a main surface and a method of manufacturing the same.

CMP (Chemical Mechanical Polishing) processes are used to polish the surface of a specific workpiece in many industries. Particularly in the field of manufacturing semiconductor devices, microelectronic devices or computer products, CMP processes are widely used for polishing ceramics, silicon, glass, quartz, metals and / or their wafers. The CMP process involves the use of a CMP pad that rotates against a workpiece such as a wafer. In addition, during the CMP process, a liquid slurry containing chemical substances and abrasive particles are added to the CMP pad.

In the field of semiconductor device fabrication, scratches and defects in the wafer during the CMP process reduce the yield and productivity of semiconductor devices. Particularly, in a CMP process for planarizing a wafer having a relatively large diameter by using a large CMP pad, the impact and stress applied to the wafer and the CMP pad are further increased. As a result, the occurrence frequency of defects such as scratches Is also higher.

Particularly important in the polishing quality by the CMP process is the distribution of abrasive particles spread widely over the entire CMP pad. The top of the CMP pad typically supports the abrasive particles by a mechanism such as fiber or small pore, and such fibers or small pores determine the performance of the CMP pad. Thus, in order to maintain the performance of the CMP pad, it is necessary to keep the upper fibrous structure of the CMP pad as flexible as possible and to secure a sufficient amount of extra voids to accommodate new abrasive particles. To this end, a conditioning or dressing process of a CMP pad by a CMP pad conditioner is required.

Conventional CMP pad conditioners are made by disposing diamond abrasive grains on the surface of a metal base material and fixing the diamond abrasive grains to a plating layer. Also, a protective layer may be formed to cover the diamond abrasive grains. However, in the conventional CMP pad conditioner, there is a high possibility that the plating layer is damaged or the diamond abrasive grains are separated from the plating layer, and scratches or the like are damaged on the pad.

One problem to be solved by the present invention is to provide a CMP pad conditioner capable of greatly reducing the frequency of defects and scratches in a CMP pad conditioning process by having a new structure in which diamond abrasives are fixed to projections formed at a desired position and a desired arrangement .

Another object to be solved by the present invention is to provide a method of manufacturing a molded body including protrusions for fixing diamond abrasive grains by forming a precise but fine protrusion in a predetermined array The present invention provides a method of manufacturing a CMP pad conditioner.

A CMP pad conditioner according to one aspect of the present invention includes a base material having a major surface. On the main surface of the base material, a plurality of projections are formed in a predetermined arrangement. One or more diamond abrasive grains are fixed on top of each of the projections.

According to one embodiment, it is preferable that the diamond abrasive grains are fixed while being partially buried in the upper portion of the projection.

According to one embodiment, the projections have a shape that converges toward the top. The shape to be converged may be, for example, approximately horn-shaped or horn-shaped.

According to one embodiment, it is preferable that the diamond abrasives fixed on the top of the projections are erected with their tips pointing upward.

According to one embodiment, it is preferable that the base material is a molding molded to have the plurality of projections integrally.

According to one embodiment, the base material may be molded from a metal, amorphous metal or polymer material.

According to one embodiment, the diamond abrasives fixed to the protrusions are divided into a plurality of groups by height difference, and each group of diamond abrasive grains preferably has a uniform height. Here, the term " homogeneous " means substantially or substantially homogeneous rather than completely uniform.

According to another embodiment, the diamond abrasives fixed to the projections have a uniform height. Here, the term " homogeneous " means substantially or substantially homogeneous rather than completely uniform.

According to another aspect of the present invention, a method of manufacturing a CMP pad conditioner is provided. This CMP pad conditioner manufacturing method includes a mold preparing step of preparing a mold having a plurality of protrusion forming holes formed by laser processing and a forming step of forming a molding material in the mold to make a molded body for a CMP pad conditioner do. The protrusions are formed on the main surface of the molded body by the protrusion forming holes.

According to one embodiment, the method for manufacturing a CMP pad conditioner further includes an abrasive-graining step of disposing diamond abrasive grains in the projection-forming holes between the mold preparing step and the forming step.

According to one embodiment, the mold preparation step includes laser machining the protrusion forming holes into a shape that converges toward the bottom.

According to one embodiment, the abrasive graining step includes disposing the diamond abrasive grains so as to be erected in the projection forming holes.

According to one embodiment, the forming material may comprise a metal, an amorphous metal or a polymer material.

According to the present invention, since the CMP pad conditioner includes protrusions of a similar shape having a predetermined arrangement, and the diamond abrasive grains are fixed on the protrusions to participate in the polishing work for the CMP pad conditioning, the cutting or cutting in the CMP pad conditioning operation The polishing performance can be maximized. The diamond abrasive grains fixed on the tops of the projections can participate in the cutting / polishing work with almost uniform height, thereby greatly reducing the number of diamond abrasive grains that can not participate in the work. The base material (or the molded body) on which the projections are formed can be made of various kinds of materials, which makes it possible to use a CMP pad conditioner by selecting a specific material in accordance with various CMP processing environments, thereby contributing to flexibly coping with various process environments . By using a laser for processing the in-mold protrusion forming holes for molding the base material (or the formed body), it is possible to precisely mold protrusions of a desired shape and a desired size into a desired arrangement. This contributes greatly to improving the accuracy and reproducibility in the manufacture of CMP pad conditioners.

1 is a plan view of a CMP pad conditioner according to an embodiment of the present invention;
Fig. 2 is an enlarged plan view of the CMP pad conditioner shown enlarged in Fig. 1; Fig.
Figure 3 is a cross-sectional view of a CMP pad conditioner taken along II of Figure 2;
Figures 4 (a), 4 (b), 4 (c) and 4 (d) are cross-sectional views illustrating various forms of CMP pad conditioners made with diamond abrasives having uniform or different heights.
5 is a conceptual diagram for explaining a mold preparing step of a method of manufacturing a CMP pad conditioner according to an embodiment of the present invention.
Fig. 6 is a photograph showing a plane and a cross-section of a protrusion forming hole formed by laser machining in the mold preparing step of Fig. 5;
Fig. 7 is a graph comparing the warpage caused when the projection-forming holes are machined by machining as a comparative example in processing a projection-in-mold hole by laser machining.
8 is a conceptual diagram for explaining a molding process of a base material using a mold according to an embodiment of the present invention.
9 is a photograph showing a part of a CMP pad conditioner made to include a base material having projections by a molding process and diamond abrasive grains fixed to the projections.
FIGS. 10A, 10B and 10C are photomicrographs showing enlarged views of the protrusions and diamond abrasives of FIG. 9; FIG.
11A is a micrograph showing the surface condition of a CMP pad conditioner sintered under conditions outside the appropriate temperature and appropriate pressure conditions
11B is a microscope photograph showing the surface condition of a CMP pad conditioner sintered at an appropriate temperature and an appropriate pressure condition.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided by way of example so that those skilled in the art can fully understand the spirit of the present invention. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms. In the drawings, the width, length, thickness, and the like of the components may be exaggerated for convenience. Like reference numerals designate like elements throughout the specification.

FIG. 1 is a plan view showing a CMP pad conditioner according to an embodiment of the present invention, FIG. 2 is an enlarged plan view of a CMP pad conditioner shown in an enlarged view of FIG. 1 A, Sectional view of a CMP pad conditioner.

1 to 3, a CMP pad conditioner according to an embodiment of the present invention includes a disk-shaped base material 10 having a main surface 11. The base material 10 may be formed by molding an amorphous metal. However, the CMP pad conditioner can be made of a different metal or polymer material according to the working environment or conditions in which the base material 10 is used.

A plurality of projections 13 are integrally formed on the main surface 11 of the base material 10. As will be described in detail below, the plurality of projections 13 are formed by protrusion forming holes previously formed in a mold in a molding process in which a molding material such as amorphous metal, metal, or polymer is put into a mold and heated and pressed. According to this, the shape, size, and arrangement of the protrusions 13 are determined by the shape, size, and arrangement of the in-mold protrusion forming holes.

As best shown in FIGS. 2 and 3, one diamond abrasive grains 20 are fixed to the upper portions of the projections 13, respectively. Although one diamond abrasive grain 20 is fixed to one projection 13 in the present embodiment, a CMP pad conditioner in which two or more diamond abrasive grains 20 are fixed on one projection 13 is also considered .

A portion of the diamond abrasive grains 20 is fixed while being buried in the upper portion of the protrusion 13. The upper portion of the diamond abrasive grains 20 is exposed through the upper portion of the protrusions 13. The exposed upper portions of the diamond abrasive grains 20 participate in polishing or cutting the object in the CMP pad conditioning process.

Each of the projections 13 has a shape that converges toward the top. The converging shape may be substantially horn-shaped or horn-shaped. It is preferable that the diamond abrasive grains 20 fixed to the upper portions of the respective projections 13 are erected and fixed with their pointed tips pointing upward.

Referring to Fig. 4 (a), it can be seen that the diamond abrasive grains 20 are located at a substantially uniform single height on the plurality of protrusions 13. Fig. In this case, the uniform height is not completely uniform, and it is considered that the height is uniform if the tolerance is within an acceptable range from the predetermined optimum height value. The diameters of the diamond abrasive grains 20 are different from each other so that the height of the diamond abrasive grains 20 fixed to the projections 13 is made uniform even if there is a difference in size between the diamond abrasive grains 20 You can do it.

For example, it is necessary to make a height difference between the diamond abrasive grains 20 in consideration of the securing of the slurry passage, the difference in pressing force between the CMP pads, and the like. Even in such a case, it may be advantageous to increase or decrease the height of the diamond abrasive grains 20 in a predetermined region or position in consideration of various conditions. However, if not, unnecessary use of the effective diamond abrasive will be wasted, The performance and reliability of the system can be reduced.

FIGS. 4 (b), 4 (c) and 4 (d) show examples of CMP pad conditioners in which the heights of the diamond grains are different from each other by designing the heights of the protrusions differently.

Referring to FIG. 4 (b), diamond abrasive grains 20a fixed to protrusions 13a having a relatively higher height form a first group, and protrusions 13b having a second height The fixed diamond abrasive grains 20b form a second group. The diamond abrasives 20a in the first group are located at a uniform single height and the diamond abrasives 20b in the second group are located at a uniform height lower than the abrasive grains 20a in the first group. At this time, the diamond abrasive grains 20a in the first group and the diamond abrasive grains 20b in the second group are alternately placed one by one.

Referring to FIG. 4C, diamond abrasive grains 20a fixed to protrusions 13a of a relatively higher first height form a first group, And the diamond abrasive grains 20b fixed to the first and second portions 13b form a second group. The diamond abrasives 20a in the first group are located at a uniform single height and the diamond abrasives 20b in the second group are located at a uniform height lower than the abrasive grains 20a in the first group. However, it is different in that one diamond grains 20b in the second group are arranged between two diamond grains 20a in the neighboring first group.

  Referring to FIG. 4 (d), diamond abrasive grains 20a fixed to protrusions 13a having relatively higher first heights form a first group, And the diamond abrasive grains 20b fixed to the first and second portions 13b form a second group. The diamond abrasives 20a in the first group are located at a uniform single height and the diamond abrasives 20b in the second group are located at a uniform height lower than the abrasive grains 20a in the first group. However, two diamond abrasives 20b in the second group are disposed between the two diamond abrasives 20a in the neighboring first group. In other respects, the third group of diamond abrasives 20c fixed to the protrusions 13c having the lowest third height are located between the adjacent two diamond abrasives 20b in the second group .

In addition to the arrangement schemes illustrated above, it is also possible to divide the diamond grains into several groups at different elevations, and to arrange the various groups of diamond grains in the intended various arrangements.

A preferred embodiment of a method of manufacturing a CMP pad conditioner as described above will now be described.

In this embodiment, amorphous metal powder is used as a molding material for molding of a base material (or a molded body) including projections. As a process before the actual molding is performed, a process for preparing the molding material will be described as follows.

<Preparation of molding material>

The amorphous metal (or amorphous alloy) has a supercooled liquid phase region (DELTA T = Tx - Tg), which is determined by the difference between the crystallization temperature (Tx) at which the alloy crystallizes and the glass transition temperature (Tg) Supercooling properties are exhibited in the supercooled liquid phase region. In this embodiment, an amorphous metal material having a crystallization temperature and a glass transition temperature is used as a molding material. It is preferable that the projections of the molded body are formed while fixing the diamond abrasive grains by the molding described below. It is preferred that the amorphous metal exhibits super plastic properties at around 600 ° C so that the diamond grains do not carbonize during the molding process. The amorphous metal may be Cu-based (e.g., Cu-Zr-Ti-Ni), Ni based (e.g., Ni-Zr-Ti-Sn, Ni- (Fe-Co-Ni-Zr-B) and Co-Co (Fe-Ta-B).

A parent alloy prepared by, for example, an arcro melting method is prepared to prepare an amorphous material. When the parent alloy is amorphous, it is preferable to select an alloy having a superplasticity property at 600 ° C or less. The parent alloy is made of amorphous powder (Mg powder) and amorphous ribbon (Mg ribbon), respectively. The parent alloy is made into an amorphous powder by an atomizing method (or gas atomization method), and the parent alloy is also made into an amorphous ribbon by a rapid solidification method.

 The amorphous powder and the amorphous ribbon are finely pulverized to a size of 1 mu m or less by using a ball mill. The ball mill is preferably performed in a low-speed rotary vessel at 100 rpm, and ultrafine pulverization is performed by ball milling in about 100 hours. Ultrafine amorphous metal powders of 1 mu m or less in size can be obtained by ultrafine powdering, followed by filtering, or by a sieving process. Next, a step of reducing the ultrafine amorphous metal powder with hydrogen may be performed. Corrosion resistance can be imparted to the ultrafine amorphous metal powder by the reduction treatment process.

Although the above-described amorphous metal has been introduced as an example of the molding material, it should be noted that other kinds of amorphous metal, or a common metal, or another material such as a polymer may be used as a molding material.

Hereinafter, a manufacturing process of a CMP pad conditioner having protrusions on a main surface of a molded body or a mother material and diamond abrasive grains fixed on the protrusions will be described.

<Preparation of mold>

As shown in Fig. 5, protrusion forming holes 110 having a shape converging in the depth direction are formed on the surface of the lower mold 100 of the mold frame. At this time, laser machining is used to form the protrusion forming holes 110. The protrusion forming holes 100 having a predetermined shape and size can be formed in such a manner that the laser beam B from the laser device L is irradiated onto the surface of the lower mold 100 of the mold frame. The laser processing conditions used in this embodiment are shown in Table 1 below.

Laser type Nd: YAG wavelength 940 nm to 1440 nm frequency 20 kHz to 1000 kHz Pulse duration 4 ns to 400 ns

In particular, the lower mold 100 can be made of, for example, stainless steel.

Fig. 6 is a photograph of a plane and a cross-section of the protrusion forming holes formed in the mold by the above-described laser machining with a three-dimensional microscope. Referring to FIG. 6, it can be seen that protrusion forming holes having a size of several tens to several hundreds of micrometers are formed in a conical shape. Although these protrusion forming holes are formed in micrometer size, they are formed smoothly with almost no deformed parts due to the characteristics of laser machining.

Fig. 7 is a graph comparing the difference in the case where the projection forming hole is formed by laser machining and the case where the projection forming hole is formed by mechanical machining. In forming the projection forming hole by mechanical working, large bending deformation occurs in the mold, It can be seen that bending deformation hardly occurs at the time of use.

<Diamond Abrasive  Batching and protrusion molding>

 When the mold frame including the lower mold 100 and the upper mold 200 in which the projecting holes are formed by the laser processing is prepared, the mold frame M is prepared and the diamond abrasive arrangement and the projection molding are performed.

8 is a diagram for explaining the diamond abrasive grain arrangement and the projection forming process.

First, the diamond abrasive grains 20 are arranged in the protrusion forming hole 110. At this time, the diamond abrasive grains 20 are disposed at the narrowest portion of the base of the projection forming hole 110. In this embodiment, one diamond abrasive grains 20 are disposed in one abrasive molding hole 110 so that one abrasive grains can fix one diamond abrasive grains, but one abrasive grains fix two or more diamond abrasive grains Two or more diamond abrasive grains are disposed at the base of the projection forming hole 110. [

Then, the molding material P is supplied between the lower mold 100 and the upper mold 200 of the mold M and the molding material P is subjected to pressure sintering molding.

In this embodiment, ultrafine amorphous metal powder is used as a molding material, and metal powder liquid paraffin can be mixed as an additive.

The base material or the molded body for the CMP pad conditioner having the protrusions on the main surface is formed by the high-temperature and high-pressure sintering molding method. Pressure conditions may vary depending on the type of the amorphous metal.

Table 2 below shows the type of amorphous metal actually sintered and the temperature and pressure conditions suitable for sintering of that type of amorphous metal.

Kinds Temperature range (℃) Pressure range (MPa) Ni-6 element 500 to 700 50 to 500 Cu-6 element 300 to 600 50 to 500

9 is a photograph showing a part of a CMP pad conditioner made to include a base material having protrusions by the molding process and diamond abrasives fixed to the protrusions, FIGS. 10A, 10B and 10C are photographs showing the protrusions of FIG. These are pictures that show the enlargement of the grains more.

Referring to FIG. 9, it can be seen that a plurality of protrusions for fixing diamond abrasive grains are arranged at regular intervals on the main surface of the base material. It is possible to manufacture a CMP pad conditioner in which protrusions are formed in a desired arrangement and each of the protrusions fixes the diamond abrasive grains by previously designing the array pattern of the protrusion holes in the mold.

10A, 10B, and 10C, it can be seen that the shapes and sizes of the protrusions formed at different positions of the base material are substantially similar. Also, it can be seen that diamond abrasive grains are fixed on the upper end of the projection having a roughly frustum shape. As described above, it is possible to form micrometer-scale fine protrusions with a desired shape and a desired size by using the projection-forming holes precisely formed by laser machining.

11A is a micrograph showing the surface state of a CMP pad conditioner sintered under a proper temperature and an appropriate pressure condition, and FIG. 11B is a micrograph showing a surface condition of a CMP pad conditioner sintered at an appropriate temperature and an appropriate pressure condition . Sintering of the amorphous metal within the appropriate pressure range and temperature range according to the type of amorphous metal can yield an amorphous metal shaped body with a smooth surface as shown in Figure 11b, When sintering at low pressure and temperature, it can be seen that the powder is formed into a coarse shape, which is a coarse shape.

10: Base material 11:
13: Projection 20: Diamond grain

Claims (13)

delete delete delete delete delete delete delete delete A method of manufacturing a CMP pad conditioner,
A mold preparing step of preparing a mold having a plurality of protrusion forming holes formed by laser machining; And
Molding the molding material in the mold to make a molded body for the CMP pad conditioner,
Wherein protrusions are formed on the main surface of the molded body by the protrusion forming holes. 10. The method of claim 9, further comprising the step of disposing diamond abrasive grains in the protrusion forming holes between the mold preparing step and the forming step. 11. The method of claim 10, wherein the mold preparation step comprises laser machining the protrusion forming holes into a shape that converges toward the bottom.  11. The method of claim 10, wherein the abrasive graining step comprises disposing the diamond abrasive grains in the protrusion forming holes. 10. The method of claim 9, wherein the forming material comprises a metal, an amorphous metal or a polymer material.

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