CN101116953A - Grinding and dressing device for chemical mechanical grinding - Google Patents

Abstract

The invention provides a grinding and trimming device applied to chemical mechanical grinding, which comprises a fixing Ring (Retaining Ring) used for embedding a wafer so as to carry out chemical mechanical grinding on a polishing pad; and a plurality of dressers (dresers) disposed around the bottom surface of the retainer ring for simultaneously dressing the polishing pad while polishing the wafer to maintain a good polishing efficiency of the polishing pad.

Description

Grinding and Dressing Device for Chemical Mechanical Polishing

technical field

The invention relates to a dressing device (Dresser) applied to chemical mechanical grinding, in particular to a dressing device attached to a chemical mechanical grinding retaining ring (Retaining Ring).

Background technique

As the line width of the semiconductor manufacturing process becomes thinner and thinner, the flatness requirements for thin film deposition in the wafer manufacturing process are also higher and higher, and the copper manufacturing process is also widely used. Chemical Mechanical Polishing (CMP) equipment has become In recent years, the increasingly critical manufacturing steps in the semiconductor manufacturing process, the equipment market demand has also grown rapidly. The CMP equipment market has grown rapidly in recent years, mainly due to the fact that the CMP process has several main advantages compared with the traditional wafer planarization process: 1. Because the surface after CMP grinding is flatter, better quality exposure and etching effects are achieved. and yield rate; 2. Better cleaning effect, reducing the impact of incomplete previous process on the next process with higher surface sensitivity. Since the CMP process can make the photolithography irradiation area more accurately aligned to the required depth, and can overcome the phenomenon of line breakage or short circuit when metal deposition is stacked between layers, the number of metal layers can be changed from 2 to 3. Layers are pushed up to layers 6 to 9.

As semiconductor manufacturing process technology continues to advance toward deep microns, the importance of wafer planarization continues to challenge various wafer fabs. Due to the rapid growth of the CMP equipment market in recent years, CMP consumables, components and abrasives required in the manufacturing process have also developed relatively rapidly. In the precise polishing process of CMP (Chemical Mechanical Planarization), the wafer is pressed against a rotating polishing pad (Pad) during polishing. Polishing pads are usually made of Polyurethane and often contain pores. The polishing pad is just a "wipe" for wiping the wafer. The protrusions on the wafer surface are polished with slurry coated on the surface of the polishing pad. Refining contains suspended abrasive particles which are similar to the line width. The refining liquor usually also contains oxidizing or corrosive agents. The liquid reacts with the wafer surface to form loose oxides, which is the chemical reaction of CMP. Abrasive particles can impact the surface of the wafer with the support of the polishing pad, which is the mechanical removal of CMP.

Please refer to FIG. 1 , which shows a schematic diagram of a conventional CMP mechanical polishing structure. As shown in the figure, the CMP machine includes a platform 11 on which a rotating polishing pad 12 is disposed, and the surface of the polishing pad 12 has a slurry 14 flowing down from a slurry dispenser 13 . And when carrying out wafer 15 surface grinding, this wafer 15 is fixed by wafer holder 16, and the periphery of this wafer 15 promptly is fixed with retaining ring (RetainingRing) 17; Perform mechanical polishing of the surface of the wafer. In general, the greater the applied pressure and relative velocity, the higher the CMP removal rate. In order to distribute the polishing liquid evenly on the surface of the polishing pad 12, the surface of the polishing pad 12 usually has grooves (about 20 μm deep) in different forms to facilitate uniform distribution of the polishing liquid. However, during grinding, the slurry doped with fractal layers will also accumulate on the surface of the polishing pad 12 to make it hard and glazing. After the contact area of polishing pad and wafer 15 increases greatly, the contact pressure of abrasive grains has been reduced, and the polishing rate of wafer will be greatly reduced like this. Furthermore, a dirty polishing pad 12 can contaminate the surface of the wafer 15 causing increased defects. In order to maintain the polishing rate and keep the wafer clean, the polishing pad 12 must be dressed (Dressing or Conditioning) with a "Diamond Disk" (Diamond Disk) 18, so that CMP can continue.

However, in actual use, the area where the CMP polishing pad 12 grinds the wafer is not the same as the area where the diamond disk 18 is used to dress the polishing pad 12 . Therefore, how to develop a dresser that applies chemical mechanical polishing to achieve the purpose of effectively dressing the polishing pad with the most streamlined structure and processing flow is the goal of active research in this related field. The present inventors, after careful research, and with their many years of experience in this research field, propose the present invention's dressing device attached to the chemical mechanical grinding retaining ring (Retaining Ring), which solves the existing problems and improves the manufacturing capacity at the same time .

Contents of the invention

The main purpose of the present invention is to provide a dressing device attached to a chemical mechanical polishing retaining ring (Retaining Ring), which can achieve the purpose of effectively dressing the polishing pad with the simplest structure. Because the present invention fixes the specific dresser on the grinding retaining ring (Retaining Ring) of CMP, it can dress the polishing pad at the same time to maintain its good polishing efficiency when the wafer is polished. And it can effectively avoid the disadvantage that the CMP retaining ring (Retaining Ring) makes it difficult for the polishing fluid to flow into the center of the wafer when its life is approaching, resulting in different polishing speeds inside and outside the wafer.

In order to achieve the above object, a broader embodiment of the present invention provides a grinding and finishing device attached to a chemical mechanical grinding fixing ring (Retaining Ring). Carrying out chemical mechanical grinding, wherein the fixing fixture also has a contact ring surface, which is used to quantitatively maintain the polishing liquid on the bottom surface of the wafer, so as to prevent too little polishing liquid from flowing into the center of the bottom surface of the wafer and cause different polishing speeds inside and outside the wafer; and a trimming unit, set A dressing surface is formed on the bottom surface of the fixing fixture for dressing the polishing pad while polishing the wafer, so as to maintain good polishing efficiency of the polishing pad.

According to the above concept, the fixing fixture further includes a retaining ring to form the contact ring surface.

According to the above concept, the trimming unit includes a plurality of trimmers, which are evenly arranged around the bottom surface of the fixing ring.

According to the above design, wherein the trimmer is a diamond disk (Diamond Disk).

According to another mode of the present invention, the present invention also provides a grinding and dressing device applied to chemical mechanical polishing, including: a retaining ring (Retaining Ring), used for embedding a wafer, so as to perform chemical mechanical polishing on a polishing pad; and a plurality of The dresser is arranged around the bottom surface of the fixed ring, and is used for dressing the polishing pad while polishing the wafer, so as to maintain good polishing efficiency of the polishing pad.

According to the above design, wherein the trimmer is a diamond disk (Diamond Disk).

According to the above concept, wherein the fixing ring is disposed on the wafer holder.

In order to achieve the above-mentioned purpose, a more broad embodiment of the present invention is to provide a grinding and dressing device for chemical mechanical polishing, including: an annular body for embedding a wafer to perform chemical mechanical polishing on a polishing pad, wherein the ring The shape body also has a contact ring surface, which is arranged on the bottom surface of the ring body to quantitatively maintain the polishing liquid on the bottom surface of the wafer, so as to prevent too little polishing liquid from flowing into the center of the bottom surface of the wafer and cause different polishing speeds inside and outside the wafer; and trimming The surface is arranged on the bottom surface of the annular body, and is used for dressing the polishing pad while polishing the wafer, so as to maintain good polishing efficiency of the polishing pad.

According to the above concept, wherein the trimming surface is arranged around the contact ring surface.

According to the above idea, wherein the annular body is composed of a retaining ring (Retaining Ring).

According to the above concept, the trimming surface is formed by a plurality of trimmers evenly arranged around the bottom surface of the fixing ring.

According to above-mentioned concept, wherein the trimmer is a diamond disk (Diamond Disk).

Description of drawings

FIG. 1 discloses a schematic diagram of a conventional CMP mechanical polishing structure.

FIG. 2 shows a grinding and dressing device attached to a chemical mechanical grinding retaining ring (Retaining Ring) according to a preferred embodiment of the present invention.

FIG. 3 discloses a schematic diagram of the grinding and dressing device of FIG. 2 in use.

Fig. 4 discloses a grinding and dressing device attached to a chemical mechanical grinding retaining ring (Retaining Ring) according to another preferred embodiment of the present invention.

simple notation

11: Platform 12: Polishing pad

13: Grinding slurry distributor 14: Grinding fluid

15: Wafer 16: Wafer fixture

17: Fixed ring 18: Diamond plate

20: Fixing fixture 21: Fixing ring

22: Dresser 23: Wafer

24: Polishing pad 25: Polishing liquid

26: Rotary platform 27: Grinding slurry distributor

41: Ring body 411: Contact ring surface

42: Dressing unit 421: Dressing surface

Detailed ways

Some typical embodiments embodying the features and advantages of the present invention will be described in detail in the description in the following paragraphs. It should be understood that the invention is capable of various changes in various ways without departing from the scope of the invention, and that the description and diagrams are illustrative in nature rather than limiting the invention.

Please refer to FIG. 2 , which shows a grinding and dressing device attached to a chemical mechanical grinding retaining ring (Retaining Ring) according to a preferred embodiment of the present invention. As shown in the figure, include retaining ring (RetainingRing) 21, in order to insert wafer, to carry out chemical mechanical grinding on polishing pad; At the same time, the polishing pad is trimmed to maintain good polishing efficiency of the polishing pad. In actual application, the plurality of trimmers 22 may be composed of a plurality of diamond disks (Diamond Disk). Of course, the fixing ring 21 is arranged above the wafer holder.

To further clearly illustrate the inventive structure of the present invention, please refer to FIG. 3 again. It is a schematic diagram illustrating the application of the grinding and dressing device in FIG. 2 . As shown in the figure, the aforesaid fixed ring 21 is a part of the fixed fixture 20, and is used for embedding the wafer 23, and the wafer 23 is chemically mechanically polished on the polishing pad 24, wherein the contact ring formed by the fixed ring 21 surface, in order to quantitatively maintain the polishing liquid 25 on the bottom surface of the wafer 23, and prevent too little polishing liquid 25 from flowing into the center of the bottom surface of the wafer to cause different polishing speeds inside and outside the wafer 23. On the other hand, one of the most important features of the present invention is that a plurality of trimmers 22 are arranged around the bottom surface of the fixed ring 21 to form a trimming unit with a trimming surface, so that when the wafer 23 is polished, At the same time, the polishing pad 24 is trimmed by a trimming unit to maintain good polishing efficiency of the polishing pad.

While the grinding and finishing device of the present invention is actually carrying out chemical mechanical grinding, the polishing pad 24 will be fixed on the rotating platform 26 in advance, and while rotating, the polishing liquid 25 flowing down from the grinding slurry distribution device 27 can be evenly distributed on the surface. on the polishing pad 24. On the other hand, the wafer 23 embedded by the fixing ring 21 undergoes chemical mechanical polishing with the polishing liquid 25 and the polishing pad 24 below it due to the rotation and pressure of the fixing fixture 20 . Of course, the most important thing is the trimmer 22 disposed around the bottom surface of the fixing ring 21 , which can trim the polishing pad 24 downward due to the rotation and pressure of the fixing fixture 20 at the same time, so as to maintain its good polishing efficiency. Therefore, the grinding and dressing structure of the present invention can simultaneously dress the polishing pad during wafer polishing to maintain overall good polishing efficiency.

Please refer to FIG. 4 , which shows another preferred embodiment of the present invention, a grinding and dressing device attached to a chemical mechanical grinding retaining ring (Retaining Ring). Comprising an annular body 41 for embedding the wafer (please also refer to FIG. 3 ) to perform chemical mechanical polishing on the polishing pad, wherein the annular body 41 also has a contact ring surface 411 disposed on the bottom surface of the annular body , in order to quantitatively maintain the polishing liquid on the bottom surface of the wafer, so as to prevent too little polishing liquid from flowing into the center of the bottom surface of the wafer and cause different polishing speeds inside and outside the wafer; When the wafer is polished, the polishing pad is trimmed simultaneously to maintain good polishing efficiency of the polishing pad. Wherein the trimming surface 421 can be constituted by a plurality of diamond discs (Diamond Disk), and the trimming unit 42 of special pattern is formed on the periphery of the contact ring surface 411. In actual application, the pattern of the trimming unit 42 is not limited, and in the present embodiment, the trimming surface 421 formed by the trimming unit 42 is an annular surface, which is similar to the contact ring surface 411, so that in use, it can Disperse the pressure applied by the fixture more evenly, and effectively avoid the disadvantage that the polishing liquid is not easy to flow into the center of the wafer when the CMP retaining ring (Retaining Ring) is approaching the end of its life, resulting in different polishing speeds inside and outside the wafer

To sum up, the present invention provides a grinding and dressing device attached to a chemical mechanical grinding retaining ring, which can achieve the purpose of effectively dressing the polishing pad with the simplest structure. Wherein, the present invention also fixes a specific dresser on the grinding retaining ring (Retaining Ring) of CMP, so the polishing pad can be trimmed simultaneously to maintain its good polishing efficiency during wafer polishing. And it can effectively avoid the disadvantage that the CMP retaining ring (Retaining Ring) makes it difficult for the polishing fluid to flow into the center of the wafer when its service life is approaching, resulting in different polishing speeds inside and outside the wafer, which cannot be achieved by the prior art.

Although the present invention has been described in detail by the above-mentioned embodiments, various changes and modifications may be made by those skilled in the art without departing from the scope as defined in the appended claims.

Claims (12)

1. A grinding and dressing device applied to chemical mechanical grinding, comprising: a fixing fixture for embedding a wafer to perform chemical mechanical polishing on the polishing pad, wherein the fixing fixture also has a contact ring surface for quantitatively maintaining the polishing liquid on the bottom surface of the wafer; and The dressing unit is arranged on the bottom surface of the fixing fixture to form a dressing surface for dressing the polishing pad while polishing the wafer so as to maintain good polishing efficiency of the polishing pad. 2. The grinding and dressing device as claimed in claim 1, wherein the fixing fixture further comprises a fixing ring to form the contact ring surface. 3. The grinding and dressing device according to claim 2, wherein the dressing unit comprises a plurality of dressers, which are evenly arranged around the bottom surface of the fixing ring. 4. The abrasive dressing device of claim 3, wherein the dresser comprises a diamond disc. 5. A grinding and dressing device applied to chemical mechanical grinding, comprising: a retaining ring to hold the wafer for chemical mechanical polishing on the polishing pad; and A plurality of dressers are arranged around the bottom surface of the fixed ring, and are used for dressing the polishing pad while polishing the wafer, so as to maintain good polishing efficiency of the polishing pad. 6. The abrasive dressing device of claim 5, wherein the dresser comprises a diamond disc. 7. The grinding and dressing device as claimed in claim 5, wherein the fixing ring is disposed on the wafer holder. 8. A grinding and dressing device applied to chemical mechanical grinding, comprising: The annular body is used for embedding the wafer to carry out chemical mechanical polishing on the polishing pad, wherein the annular body also has a contact ring surface, which is arranged on the bottom surface of the annular body to quantitatively maintain the polishing liquid on the bottom surface of the wafer ;and The dressing surface is arranged on the bottom surface of the annular body, and is used for dressing the polishing pad while polishing the wafer, so as to maintain good polishing efficiency of the polishing pad. 9. The abrasive dressing device of claim 8, wherein the dressing surface is disposed around the contact ring surface. 10. The grinding and dressing device as claimed in claim 8, wherein the annular body is constituted by a fixed ring. 11. The grinding and dressing device as claimed in claim 10, wherein the dressing surface is formed by a plurality of dressers evenly arranged around the bottom surface of the fixing ring. 12. The abrasive dressing device of claim 11, wherein the dresser comprises a diamond disc.

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