ENDPOINT WINDOW WITH CONTROLLED TEXTURE SURFACE
A chemical mechanical polishing pad window having a controlled texture surface comprising repeated patterned features. The window results in an improved endpoint detection and in situ rate monitoring by providing consistent values of the ISRM max-min characteristic over the lifetime of a CMP pad. Also provided is a chemical mechanical polishing pad with the inventive window.
1 . A window for a chemical mechanical planarization (CMP) pad, the window comprising a material transmissive to light, wherein a first surface of the window has a controlled texture surface comprising repeated patterned features.
2 . The window of claim 1 , wherein the first surface corresponds to a bottom surface of the CMP pad which does not contact a substrate being planarized during a CMP process using the CMP pad.
3 . The window of claim 1 , wherein the repeated patterned features are configured to diffuse light passing through the window.
4 . The window of claim 1 , wherein the repeated patterned features comprise regularly spaced raised features.
5 . The window of claim 4 , wherein the repeated patterned features comprise a crosshatch pattern.
6 . The window of claim 4 , wherein the repeated patterned features comprise rounded ridges.
7 . The window of claim 5 , wherein the rounded ridges are randomly roughened.
8 . The window of claim 2 , wherein a second surface opposite the first surface corresponds to a top surface, the top surface is capable of contacting a substrate being planarized during a CMP process using the CMP pad, wherein the top surface has a roughened texture corresponding to an average surface roughness in a range from about 1 to about 50 micrometers.
9 . The window of claim 1 , wherein:
the window has a width and length that is less than the width, wherein the width and the length characterize physical dimensions of the window; and
the repeated patterned features comprise:
a first set of regularly spaced raised features parallel to a direction of the width of the window; and
a second set of regularly spaced raised lines at an angle relative to the first set of regularly spaced raised features.
10 . The window of claim 1 , wherein:
the window has a width and length that is less than the width wherein the width and the length characterize physical dimensions of the window; and
the repeated patterned features comprise a crosshatch texture comprising:
a first set of regularly spaced features in the first surface at a first angle relative to a direction of the width of the window; and
a second set of regularly spaced features in the first surface at a second angle relative to the first set of lines, wherein the first angle is different than the second angle.
11 . A chemical mechanical planarization (CMP) pad comprising:
a top surface which contacts a substrate being planarized during a CMP process using the CMP pad;
a bottom surface opposite the top surface; and
a window that allows light to pass between a top side of the CMP pad associated with the top surface and a bottom side of the CMP pad associated with the bottom surface, the window comprising a material transmissive to light, wherein a first surface of the window has repeated patterned features.
12 . The CMP pad of claim 11 , wherein the first surface of the window faces the same direction as the bottom surface of the CMP pad which does not contact the substrate being planarized during a CMP process using the CMP pad.
13 . The CMP pad of claim 11 , wherein the repeated patterned features are configured to diffuse light passing through the window.
14 . The CMP pad of claim 11 , wherein the repeated patterned features comprise regularly spaced raised features.
15 . The CMP pad of claim 11 , wherein the repeated patterned features comprise a crosshatch pattern.
16 . The CMP pad of claim 11 , wherein the repeated patterned features comprise rounded ridges.
17 . The CMP pad of claim 16 , wherein the rounded ridges are randomly roughened.
18 . The CMP pad of claim 11 , wherein a second surface opposite the first surface corresponds to a top surface, the top surface is capable of contacting a substrate being planarized during a CMP process using the CMP pad, wherein the top surface has a roughened texture corresponding to an average surface roughness in a range from about 1 to about 50 micrometers.
19 . The CMP pad of claim 11 , wherein:
the window has a width and length that is less than the width, wherein the width and the length characterize physical dimensions of the window; and
the repeated patterned features comprise:
a first set of regularly spaced raised features parallel to a direction of the width of the window; and
a second set of regularly spaced raised lines at an angle relative to the first set of regularly spaced raised features.
20 . The CMP pad of claim 11 , wherein:
the window has a width and length that is less than the width wherein the width and the length characterize physical dimensions of the window; and
the repeated patterned features comprise a crosshatch texture comprising:
a first set of regularly spaced features in the first surface at a first angle relative to a direction of the width of the window; and
a second set of regularly spaced features in the first surface at a second angle relative to the first set of lines, wherein the first angle is different than the second angle.
a window as disclosed herein.