TWI565557B - Chemical mechanical polishing process - Google Patents

Description

Chemical mechanical polishing process

The present invention relates to a chemical mechanical polishing (CMP) process.

In semiconductor manufacturing, chemical mechanical polishing (CMP) technology is currently the most commonly used and the most important planarization technology. In general, CMP technology uses a suitable polishing slurry and mechanical polishing to uniformly remove a target thin film having an irregular surface on a semiconductor wafer, so that the semiconductor wafer is subjected to CMP treatment. It is possible to have a flat and planar surface. Among them, the polishing slurry is generally composed of a chemical auxiliary agent and an abrasive powder, and the chemical auxiliary agent may be a pH buffering agent, an oxidizing agent or a surfactant, and the abrasive powder may be a component such as alumina or alumina. . The wafer surface can be effectively planarized by the chemical reaction provided by the chemical auxiliaries and the mechanical grinding effect between the abrasive powder and the wafer and the polishing pad.

Current chemical mechanical polishing processes typically perform a parametric test on a dummy wafer prior to grinding the actual product wafer, such as grinding the test wafer while scraping the abrasive particles on the surface of the polishing pad with a grinding knife. The actual product wafer is ground after some grinding environment is required that is close to the actual product wafer. However, using the test wafer to obtain the grinding environment not only increases the process cost, but also easily affects the grinding of subsequent product wafers due to the partial residue falling on the polishing pad during the grinding process. because How to improve the current CMP process is an important issue today.

A preferred embodiment of the invention discloses a chemical mechanical polishing process. First, a chemical mechanical polishing machine is provided, and the machine includes a polishing pad. A warming step is then performed wherein the warming step includes providing a polishing slurry and subjecting the polishing pad to a particle scraping action using a grinder. A polishing step is then performed to grind a product wafer.

12‧‧‧ polishing pad

14‧‧‧Mr.

16‧‧‧ wafer carrier

18‧‧‧ Grinding platform

20‧‧‧Expanding the arm

22‧‧‧grinding knife

24‧‧‧ polishing head

26‧‧‧ Feeding tube

28‧‧‧ polishing slurry

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic perspective view of a chemical mechanical polishing process in accordance with a preferred embodiment of the present invention.

Figure 2 is a plan view showing the chemical mechanical polishing process of the preferred embodiment of the present invention.

Please refer to FIG. 1 to FIG. 2 . FIG. 1 is a schematic perspective view showing a chemical mechanical polishing process according to a preferred embodiment of the present invention, and FIG. 2 is a schematic plan view showing a chemical mechanical polishing process according to a preferred embodiment of the present invention. As shown in FIG. 1-2, a polishing pad 12, a grinder 14 and a wafer carrier 16 are first provided. The polishing pad 12 is preferably disposed on a platen 18, and the grinder 14 includes a delay. The sharpening arm 20 and a grinding blade 22 have a polishing head 24 at the end of the wafer carrier 16. A slurry feed 26 is provided alongside the polishing pad 12 to provide a polishing slurry 28 to the polishing pad 12 during the grinding process.

In a typical chemical mechanical polishing process, the wafer carrier 16 preferably detachably mounts a wafer to a polishing pad, wherein the wafer can be a test wafer or an actual wafer. A product wafer on which integrated circuit components such as semiconductors are fabricated. The wafer carrier 16 is then subjected to a lower pressure to bring the wafer into contact with the polishing pad 12, and a polishing slurry 28 is introduced into the polishing pad 12 through the feeding tube 26 for a grinding process. The grinder 14 scrapes off the abrasive particles attached or blocked on the surface of the polishing pad 12 by the downward pressure of the grinding blade 20 and the rotation of the grinding blade 22 during the grinding process, thereby preventing the clogging abrasive particles from affecting the grinding efficiency.

In the present embodiment, the present invention preferably directly scrapes the polishing pad 12 by the grinder 14 after the booting and when the warming machine is used without using any test wafer, and is in the grinder 14 and During the interaction of the polishing pad 12, at least one of the grinding parameters is selectively adjusted to obtain a grinding recipe. The resulting abrasive formulation pair is then applied to an actual product wafer. In addition, in another embodiment of the present invention, in addition to the scraping action of the polishing pad 12 by the grinder 14 during warming up, the polishing head 24 of the wafer carrier 16 also grinds without carrying the wafer. The mat 12 is ground.

More specifically, the operation of adjusting the at least one polishing parameter in the embodiment may include adjusting the operation of the polishing pad 12, the operation of the polishing device 14, the operation of the wafer carrier 16, and the operation of supplying the polishing slurry 28, wherein the three are adjusted. The more detailed operation includes adjusting the rotational speed of the polishing pad 12, adjusting the downward pressure of the polishing blade 20 of the grinder 14, adjusting the rotational speed of the polishing blade 22 of the grinder 14, adjusting the pressure under the wafer carrier 16, and adjusting the wafer carrier 16 Various parameters such as the number of revolutions of the polishing head 24 and the flow rate of the polishing slurry 28 supplied to the polishing pad 12 are adjusted. It should be noted that the present invention preferably selectively adjusts the flow rate of the polishing pad 12, the wafer carrier 16 and/or the polishing slurry 28 while adjusting the operation of the grinder, wherein the polishing pad 12, the grinder 14 and the wafer carrier are adjusted. The action of 16 and the flow rate of the slurry 28 is not limited to one parameter or all of the parameters, and any combination of the relevant parameters may be selected for adjustment according to the process requirements. For example, the visual process requirements of this embodiment are Adjusting the action of the grinder 14 includes adjusting the downforce of the lapping arm 20 of the grinder 14 and/or the rotational speed of the lapping blade 22 of the grinder 14 to selectively adjust the flow of the polishing pad 12, wafer carrier 16 and polishing slurry 28. One of the parameters, for example, only adjusting the rotational speed of the polishing pad 12, the rotational speed of the polishing head 24 of the wafer carrier 16, the downward pressure of the wafer carrier 16, or simultaneously adjusting two or more parameters, such as simultaneously adjusting the wafer carrier 16 The downward pressure and the flow rate of the polishing slurry 28, the rotational speed of the polishing head 24 of the wafer carrier 16 and the flow rate of the polishing slurry 28, and even the rotational speed of the polishing pad 12, the pressure under the wafer carrier 16, the wafer carrier All the parameters, such as the number of revolutions of the polishing head 24 of 16 and the flow rate of the polishing slurry 28 supplied to the polishing pad 12.

In this embodiment, after the combination of the selected grinding parameters to be selected, the present invention preferably combines the selected grinding parameters into a grinding recipe, and then applies the grinding recipe to an actual product wafer. In general, the present invention preferably performs the action of scraping the abrasive pad directly on the polishing pad by using a grinder without using any test wafer during a warm-up step, and can selectively adjust other grinding parameters. By obtaining a polishing formulation and directly grinding the product wafer, the cost of using the test wafer and the disadvantages of using the test wafer to affect the polishing pad can be greatly reduced, thereby improving the efficiency of the entire CMP process.

The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

12‧‧‧ polishing pad

14‧‧‧Mr.

16‧‧‧ wafer carrier

18‧‧‧ Grinding platform

20‧‧‧Expanding the arm

22‧‧‧grinding knife

24‧‧‧ polishing head

26‧‧‧ Feeding tube

28‧‧‧ polishing slurry

Claims (8)

A chemical mechanical polishing process comprising: providing a chemical mechanical polishing machine, the chemical mechanical polishing machine comprising a polishing pad; performing a warming step, the warming step comprising providing a polishing slurry and using a grinder The polishing pad performs an action of scraping the abrasive particles, and adjusting at least one polishing parameter to obtain a polishing recipe; and performing a grinding step of grinding a product wafer with the polishing formulation. The chemical mechanical polishing process of claim 1, wherein the chemical mechanical polishing machine further comprises a wafer carrier, and the warming step further comprises directly grinding the polishing pad by using the polishing head of the wafer carrier. . The chemical mechanical polishing process of claim 1, wherein the step of adjusting the at least one grinding parameter comprises adjusting the flow rate of the polishing slurry. The chemical mechanical polishing process of claim 2, wherein the step of adjusting the at least one grinding parameter comprises adjusting the pressure under the wafer carrier. The chemical mechanical polishing process of claim 2, wherein the step of adjusting the at least one polishing parameter comprises adjusting a rotational speed of the polishing head of the wafer carrier. The chemical mechanical polishing process of claim 1, wherein the step of adjusting the at least one polishing parameter comprises adjusting a rotational speed of the polishing pad. The chemical mechanical polishing process of claim 1, wherein the step of adjusting the at least one grinding parameter comprises adjusting a pressure under the grinding arm of the grinder. The CMP process of claim 1, wherein the step of adjusting the at least one grinding parameter comprises adjusting a rotational speed of the grinding blade of the grinder.