JP2001105326A - Reconditioning disk for chemical-mechanical polishing mat and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent abrasive grains from being welded partially to or let fall on a correcting disk. SOLUTION: Abrasive grains are arranged in regular positions on a welding material layer of metal via a template, and are welded thereto. The metal welding material layer is then coated with a diamond or diamond-like carbon layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a modified disk for modifying a chemical mechanical polishing mat, and more particularly to a modified disk in which abrasive particles are regularly arranged on a surface of a substrate layer.

2. Description of the Related Art A silicon wafer, which is the main material in the semiconductor industry, can be used for the production of chips only by making the surface of the deposited layer extremely smooth. Therefore, the surface of the deposited layer must be precisely processed using a polishing method or the like. For example, when using a polishing method to smooth the deposited layer surface, in addition to polishing with fine abrasive particles contained in the polishing liquid, an acid solution is always added to the polishing liquid to accelerate erosion. . The combination of such mechanical and chemical methods is referred to as CMP (chem.
ical mechanical polishing). When performing CMP, a plurality of silicon wafers are covered with disks, respectively, pressed on a rotating polishing mat, and a polishing liquid is injected into the mat from the suspension arm. Depending on the material to be polished, whether the polishing liquid is made acidic or alkaline is selected. For example, an alkaline liquid is often used for an oxide, and an acidic liquid is often used for polishing a metal material (for example, tungsten or copper). Most of the debris generated during polishing is washed away with the water flow, but some debris may be mixed into the polishing mat. Then, the polishing mat hardens due to accumulation of mixed debris, and loses the polishing function. Therefore, when performing polishing, the life of the polishing mat can be greatly extended by removing the debris of the polishing mat as needed using a modified disk. For example, if the polishing mat debris is not removed, before polishing hundreds of 8-inch wafers (each one for about one minute), excessive debris accumulates on the polishing mat and the polishing speed is significantly reduced, and the polishing mat is not used. Sometimes it is impossible. However, during polishing, the life of the polishing mat can be extended to 500 sheets or more by removing the debris with the modified disk. Also,
The modified disk has the function of removing debris and can also roughen the surface of the polishing mat. In this case, polishing is performed by adhering the suspended abrasive particles to the surface of the polishing mat, and the modified disk can evenly disperse the free abrasive material throughout the polishing mat to increase the polishing efficiency.

Heretofore, diamond-plated disks have often been used as modified disks. As shown in FIG. 2, the diamond 21 is embedded in a nickel layer 22, which is a plating applied to the surface of the modified disk 20, and the diamond 21 is merely mechanically locked in position. The adhesion is very loose and easily falls off when rubbing the polishing mat, damaging expensive wafers. Occasionally, the debris that has accumulated in the hole 220 from which the diamond has fallen may fall off and damage the wafer. Even if the diamond is not dropped, the adhesion of diamond by plating is difficult to effectively modify the polishing mat because the amount of diamond protruding from the plating is small, and the plated modified disk is usually Since the shape is irregular, it is difficult to say that the polishing mat has a high retouching effect. Also, since the distribution of diamonds is not uniform,
The efficiency of removing debris is also low. Further, the nickel plating used for attaching diamond has a relatively high dissolution rate in an acidic solution, so that the diamond is easily dropped. Another type of modified disk, as shown in FIG. 3, uses an alloy to weld diamond to the modified disk surface, which improves the adhesion of diamond 31 to modified disk 30. However, the problem of nonuniform diamond distribution could not be solved. Moreover, the diamond is attracted during welding by the melted welding material and becomes mountain-shaped, so that the distribution of diamond is biased, thereby reducing the effect of modifying the polishing mat and increasing the thickness of the welding material layer 32 due to the leaning of the diamond 31. , And it becomes difficult to remove debris. Also, outside of the diamond welding becomes loose,
Since it becomes difficult to remove debris and the impact force is concentrated,
The diamond may easily fall off and damage the wafer. Since the diamonds are far apart from each other, the welding material layer becomes thinner, and the recessed portion becomes a place for accumulation of debris. In addition, when a diamond is adhered by a hard welding method, it is inevitable that the welding material is eroded by an acidic liquid, and thus the diamond is easily dropped. That is, the conventional modified disk has the following disadvantages. 1. Diamond adhesion inconsistent; damage to wafer due to diamond particles falling off. 2. Inhomogeneous diamond distribution; debris cannot be effectively removed due to distant pitch. 3. The binder is eroded by the acidic solution; the acidic solution erodes the binder that binds the diamond, loosening the bond and causing the diamond to fall off. 4. Inability to control the amount of protrusion of the diamond; if the amount of protrusion is not sufficient, the abrasive material cannot be dispersed, the fibers cannot be scraped out, and the debris cannot be removed; if the amount of protrusion is excessive, a polishing mat 4. destroy Insufficient hardness of binder; easily worn by polishing liquid. In view of the fact that the conventionally used modified disk cannot satisfy the user's requirements, the present inventors have thoroughly studied the above disadvantages, and have abrasive particles having a uniform distribution and a firm bond. A chemical mechanical polishing mat modified disk and its manufacturing method have been developed. SUMMARY OF THE INVENTION The main object of the present invention is to provide a chemical mechanical polishing mat modified disk and a method of manufacturing the same, which is capable of uniformly and stably welding abrasive particles to a modified disk by an appropriate processing method. The purpose is to provide the best effect on the modification of the dynamic polishing mat.

According to another aspect of the present invention, there is provided a chemical mechanical polishing mat modified disk comprising abrasive particles dispersed in a uniform concentration on a substrate layer. Is welded onto the substrate layer with a welding material. In addition, the method for producing a modified disk of claim 17 further includes the step of dispersing the abrasive particles at a uniform concentration on the substrate layer through one predetermined shape template having perforations. Welding the abrasive particles onto the substrate layer with a welding material. In the method for manufacturing a modified disk with a chemical mechanical polishing mat according to claim 19, a thin metal layer having a uniform thickness is manufactured as a welding material, and the abrasive particles are dispersed at a uniform concentration on the substrate layer. And a step of welding the abrasive particles onto the substrate layer with a welding material. In addition, the method for producing a modified disk for polishing a chemical mechanical polishing mat according to claim 21 includes a step of spraying the abrasive particles at a uniform concentration on the substrate layer, and a step of welding the abrasive particles to the substrate layer with a welding material. The welding surface is coated with one layer of diamond or diamond-like carbon (DLC). In the case of diamond-like carbon, a step of forming the same using physical vapor deposition (PVD) is provided.

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail. As shown in FIG. 1, the modified disk of the present invention has one metal substrate layer, and the metal substrate layer is manufactured using stainless steel. Abrasive particles 11 are arranged on the surface of the metal substrate layer, and the particle size of the abrasive particles 11 is usually 100 to 350 μm, and the difference in particle size of the different abrasive particles 11 is usually 50 μm.
m. The pitch of each abrasive particle 11 is usually 1.5 to 6 times the particle size, and the difference in peak height of the abrasive particles is less than 100 μm.
Is usually formed with a thickness of 10 to 90% of the particle size of the abrasive particles. Further, the components of the metal welding material layer 12 contain a small amount of
(> 2 wt%), it is possible to provide extremely good hardness and abrasion resistance. Next, a method for manufacturing a modified disk of a chemical mechanical polishing mat according to the present invention will be described. First, after mixing the welding material itself or its powder with an organic adhesive (eg, wax), a thin metal layer having a uniform thickness is formed using a roller. Abrasive particles (diamond or cubic boron nitride) are then introduced into the weld metal layer using a template having regularly distributed holes. Since the abrasive particles are introduced using the template, they are regularly arranged in the metal layer of the welding material, and thereafter, the welding is performed. When welding is performed through such a process, the abrasive particles are forcibly positioned, so that a regular matrix arrangement is formed. Also, the hole in the template is larger than one abrasive particle,
By making the size smaller than two abrasive particles, only one abrasive particle can be stored in each hole. Since the welding material metal layer used in the present invention has a very uniform thickness, it is coated thereon with a further thin layer of diamond or diamond-like carbon (DLC) (<3 μm). be able to. At this time, 95 of the elements contained in diamond-like carbon
% Or more is a carbon atom. DLC is a physical vapor deposition method.
It can be formed on a modified disk using Vapor Deposition (PVD), and the physical vapor deposition method used a cathode arc using a graphite cathode. DLC has acid resistance and alkali resistance, and is not eroded by using, for example, aqua regia (AQUAREGIA). Therefore, it can be ensured that the welding material is not melted. In particular, DLC covers the surface of the metal layer of the welding material, thereby preventing the metal of the modified disk from dissolving in the polishing liquid, thereby preventing contamination of the silicon chip. In the modified disk manufactured in the present invention,
In addition to making the distribution of the abrasive particles uniform, the abrasive particles can be arranged in a desired pattern. Abrasive particles 1 used in the present invention
1 has a crystal having a good surface (having a crystal of a crystal plane), and one sharp corner of the abrasive particles 11 is set in a state of going away from the surface of the substrate layer. According to the present invention, the pitch of the abrasive particles 11 can be controlled, so that it is possible to quickly remove debris from the polishing mat. Further, by disposing the abrasive particles 11 in a complete matrix arrangement, the abrasive material is evenly dispersed. be able to.
In addition, since the thickness of the welding material 12 is uniform and can be controlled, the protrusion amount of the abrasive particles 11 reaches the best value, it can be ensured that the abrasive particles 11 do not fall off, and the removal of debris is smooth, Adhesion can be avoided, and the application of DLC can protect the modified disk 10 from attack by acids and alkalis, greatly extending the useful life of the polishing mat.

The present invention relates to a chemical mechanical polishing mat modified disk and a method for producing the same, which is capable of uniformly dispersing the abrasive particles on the surface of the modified disk substrate layer and having a metal layer having a uniform thickness. It provides a good retouching effect on the polishing mat of the wafer and has a considerably long service life.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a modified disk according to the present invention.

FIG. 2 is a cross-sectional view of a traditional diamond-plated disk.

FIG. 3 is a sectional view of a traditional diamond welding disk.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Modification disk 11 ... Abrasive particle 12 ... Welding material layer 20, 30 ... Modification disk 21, 31 ... Diamond 22 ... Plating layer 32 ... Welding material layer 220 ... Hole

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3C047 EE18 3C058 AA07 AA19 BC02 CB01 CB03 DA12 DA17 3C063 AA10 BA37 BB02 BB07 BB24 BC02 BG01 BG07 CC11 FF23

Claims (22)

[Claims] 1. A chemical mechanical polishing mat modifying disk comprising abrasive particles dispersed at a uniform concentration on a substrate layer, wherein the abrasive particles are welded onto the substrate layer with a welding material. . 2. The disk as claimed in claim 1, wherein the abrasive particles are diamond or cubic boron nitride. 3. The disk as claimed in claim 1, wherein the substrate layer is made of a metal. 4. The disk as claimed in claim 3, wherein the metal is stainless steel. 5. The chemical mechanical polishing mat modified disk according to claim 1, wherein the abrasive particles are dispersed at predetermined positions. 6. The modified disk of claim 1, wherein the abrasive particles are welded using a nickel alloy containing at least 2 wt% chrome. 7. The abrasive particles have a particle size of 100 to 350.
2. The modified disk of claim 1, wherein the thickness is between .mu.m. 8. The modified disk according to claim 1, wherein the difference in particle size of the abrasive particles is 50 μm or less. 9. The disk as claimed in claim 1, wherein the difference between the peak heights of the respective abrasive particles is 50 μm or less. 10. The distance between the polishing particles is 1.
6. The disk as claimed in claim 5, wherein the ratio is 5 to 6 times. 11. The thickness of the weld is between 10% and 90% of the grain size.
%. 3. The modified disk of claim 1, wherein 12. The chemical mechanical polishing mat modified disk according to claim 1, wherein the abrasive particles are crystals having a good crystal form. 13. The abrasive particles have one sharp corner,
2. The disk as claimed in claim 1, wherein the corner is formed in a direction away from the surface of the substrate layer. 14. The modified disk of claim 1, wherein the welding surface is coated with a layer of diamond or diamond-like carbon (DLC). 15. The modified disk of claim 14, wherein the thickness of the coating layer is less than 3 μm. 16. The diamond-like carbon is 9
15. The disk of claim 14 having at least 5% carbon atoms. 17. The method as claimed in claim 1, wherein the abrasive particles are attached via a template having a predetermined shape with perforations. 18. The method of claim 17, wherein the size of the perforations is larger than one abrasive particle and smaller than two abrasive particles. 19. The method according to claim 1, wherein a thin metal layer having a uniform thickness is manufactured as the welding material.
Of manufacturing a modified disk of chemical mechanical polishing mat. 20. The method of claim 19, wherein the thin metal layer is manufactured by pressing with a roller. 21. The method of claim 14, wherein the diamond-like carbon is coated by a physical vapor deposition (PVD) method. 22. The method of claim 21, wherein the physical vapor deposition method is completed by a cathodic arc using a graphite cathode.