Patent Application
20080045125
Reference will now be made in detail to embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings.
Referring to
A polishing table 230 having the polishing pad 210 thereon rotates, and a head 240 applies a predetermined pressure to the wafer 200 and also rotates.
In many embodiments, the weight of and pressure applied by the head 240 causes the surface of the wafer 200 to contact the polishing pad 210. The slurry 220, which is typically a processing or polishing solution, flows into fine gaps between contacting surfaces. The fine gaps can be trench patterns on the polishing pad (which will be described later). The polishing particles in the slurry 220 and protrusions on the surface of the polishing pad 210 perform a mechanical polishing process on the wafer 200. Additionally, chemical components in the slurry 220 chemically polish the wafer 200.
In certain embodiments, a supporting ring 250 and a baking film 260 may be formed between the wafer 200 and the head 240 and perform supporting and shock-absorbing functions.
In an embodiment, a pad conditioner 270 is included on the polishing pad 210 to remove polishing by-products and increase polishing efficiency and uniformity. The pad conditioner 270 is typically driven up and down on the polishing pad 210 by a pneumatic cylinder (not shown), and includes a cylindrical body connected to the pneumatic cylinder and a diamond disk surrounding an outer circumference of the cylindrical body.
As illustrated in
In an embodiment, a plurality of trenches is formed around the groove 211 and can receive the slurry. Each trench has a predetermined pattern, such as a first pattern 212 and a second pattern 213. The first pattern 212 and second pattern 213 each comprise a herringbone design, though the joint of the herringbone opens in opposite directions in first pattern 212 and second pattern 213. The joints can be curved to form U-like herringbone shapes or rigid to form V-like herringbone shapes. In certain embodiments, all joints are rigid. In further embodiments, all joints are curved. In yet further embodiments, some joints are curved and some joints are rigid.
In certain embodiments, when the polishing pad 210 has a circular shape, the groove 211 also has a circular shape and is concentric with the outside circumference of the polishing pad 210. A plurality of the first patterns 212 is formed on the polishing pad concentrically around the groove 211. A plurality of the second patterns 213 is also formed concentrically around the groove 211 and trenches of each pattern are alternated as you move away from the groove 211 in either direction.
Thus, in certain embodiments, a first line 212a is formed by the first pattern 212, and a second line 213a is formed by the second pattern 213. Moving away from the center of the polishing pad 210 toward its outer circumference, first line 212a and second line 213a are alternately disposed.
In many embodiments, the first pattern 212 and the second pattern 213 each have a herringbone shape, but with the opening of the shape for one pattern facing the direction the polishing pad 210 rotates and the opening of the shape for the other pattern facing the opposite direction.
In an embodiment, the first pattern 212 and the second pattern 213 may each have a rounded bracket shape instead of a rigid angle. Typically, when the round bulge or sharp portion of the rounded bracket shape is disposed in the direction the polishing pad 210 is rotating, it is referred to as the second pattern 213; otherwise, it is referred to as the first pattern 212.
As illustrated in
In many embodiments, the first pattern 212 and the second pattern 213 each have a bulge of a predetermined size. The bulge inside the second pattern 213 is formed in a direction opposite the rotating direction of the polishing pad 210.
As seen in
In many embodiments, the second pattern 213 can have the same ranges of values for α, β, Lp, L, and r as the first pattern 212. Additionally, the second pattern 213 can have trenches of a concave shape, as shown for the first pattern 212 in
Referring the embodiment shown in
In an embodiment, the herringbone designs of the first pattern 212 and the second pattern 213 have opposite directions. By using air generated from rotations of the polishing pad 210 and the head 240, the pressure applied by the head 240 is uniformly distributed on the wafer 200.
The uniformly-applied pressure of the head 240 causes the polishing rate at each point of the wafer 200 to be approximately the same.
As illustrated in
In an embodiment, the trenches on the polishing pad 210 from the first pattern 212 line up with the trenches from the adjacent second pattern 213, such that the boundaries of the length Lp for trenches in the first pattern 212 are directly across from boundaries of the length Lp for trenches in the second pattern 213. In an alternative embodiment, the trenches on the polishing pad 210 from the first pattern 212 do not line up with the trenches from the adjacent second pattern 213.
In an embodiment, the polishing pad 210 has rows of a third pattern going circumferentially around the polishing pad 210. The third pattern has a design which is similar to two opposing herringbone designs connected; the designs have a first trench which then connects to a second trench which then connects to a third trench that is approximately parallel to the first trench. In one embodiment, the three trenches are each approximately the same length and width. In another embodiment, the second trench is approximately twice as long as the first and second trench. This can be accomplished by connecting the first pattern 212 and the second pattern 213 to form the third pattern. In an embodiment, adjacent third patterns have the boundary line length Lp of the trenches line up. In an alternative embodiment, the boundary line length Lp of trenches in adjacent patterns do not line up. In an embodiment, the joints are rigid. In a further embodiment, the joints are curved. In another embodiment, some joints are curved and some joints are rigid. In yet another embodiment, the polishing pad 210 has a circular groove 211, which is concentric with the outside circumference of the polishing pad 210.
In a further embodiment, the polishing pad 210 has rows of directionally alternating third patterns going circumferentially around the polishing pad 210. In another embodiment, alternating rows of first and second patterns can include a number of rows of first patterns followed by a number of rows of second patterns followed by a number of rows of first patterns.
Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification do not necessarily all refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is to be understood that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments.
Although the invention has been described with reference to certain embodiments, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure and the appended claims. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings, and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2006-077396 | Aug 2006 | KR | national |
