Search

KR-20260064327-A - POLISHING PAD FOR MAINTAINING TRANSMITTANCE AND PREPARATION METHOD THEREOF

KR20260064327AKR 20260064327 AKR20260064327 AKR 20260064327AKR-20260064327-A

Abstract

A polishing pad according to one embodiment comprises a top pad having three or more through holes and a plurality of grooves; and a window block inserted into the lower portion of each of the through holes, wherein the upper portion of the through holes that is not filled with the window block forms a groove, and the ratio of the depth of the groove to the thickness of the top pad is 0.1 to 0.4, and the groove is connected to the groove. The polishing pad according to the embodiment minimizes the occurrence of scratches on the window surface during the CMP process and facilitates the discharge of polishing residue through the grooves, thereby preventing a decrease in transmittance caused by scratches and residue.

Inventors

  • 이도형
  • 서장원
  • 윤종욱
  • 김영환
  • 김경환
  • 박상규

Assignees

  • 엔펄스 주식회사

Dates

Publication Date
20260507
Application Date
20241031

Claims (10)

  1. A top pad having three or more through holes and a plurality of grooves; and It includes a window block inserted into the lower part of each of the above-mentioned through holes, and In the above through hole, the upper portion that is not filled with the window block forms a groove, and The ratio of the depth of the groove to the thickness of the top pad is 0.1 to 0.4, and The above groove is a polishing pad connected to the above groove.
  2. In Article 1, The above window block is a polishing pad having a thickness of 1.2 mm to 1.6 mm.
  3. In Article 1, The above polishing pad is A polishing pad having a full vision window structure in which three or more window blocks are arranged at equal intervals.
  4. In Article 1, The above polishing pad further includes a lower pad bonded to the lower surface of the above top pad, and The lower pad above is a polishing pad having a through hole corresponding to each through hole of the top pad.
  5. In Article 4, The diameter of the through hole in the top pad above is A polishing pad having a diameter of 1.1 to 2.0 times the diameter of the through hole of the lower pad.
  6. In Article 1, The above top pad is A plurality of first grooves having the shape of concentric circles, and It includes at least one type among a plurality of second grooves having a radial straight shape, and A polishing pad in which the first groove and the second groove are connected to a groove formed on the upper part of the through hole.
  7. In Article 1, The above abrasive pad is an abrasive pad having a pressure difference (ΔP) of 3 mbar or less according to the following formula: ΔP = P1 - P2 Here P1 is the pressure (mbar) applied to the through hole into which the window block is inserted in the top pad in a sealed state, and P2 is the pressure (mbar) measured after applying the pressure of P1 to the above-mentioned through hole for 5 minutes in a sealed state.
  8. In Article 1, A polishing pad having a transmittance of 6.0% or more at a wavelength of 440 nm when measuring the transmittance of the window block, after performing chemical mechanical polishing (CMP) on a silicon oxide film of a wafer for 1 minute under conditions of a polishing load of 4.0 psi and a polishing pad rotation speed of 150 rpm while supplying silica slurry to the polishing pad at a rate of 250 mL/min.
  9. A step of manufacturing a top pad having three or more through holes and a plurality of grooves; A step of joining the above top pad to the lower pad; and The method includes the step of inserting a window block into the lower part of the through hole of each of the top pads. In the above through hole, the upper portion that is not filled with the window block forms a groove, and The ratio of the depth of the groove to the thickness of the top pad is 0.6 to 0.8, and A method for manufacturing a polishing pad in which the above groove is connected to the above groove.
  10. A method for manufacturing a semiconductor device, comprising the step of performing chemical mechanical polishing (CMP) on the surface of a semiconductor substrate using a polishing pad of claim 1.

Description

Polishing pad for maintaining transmittance and method for manufacturing the same An embodiment relates to a polishing pad used in a chemical mechanical polishing (CMP) process of a semiconductor device and a method for manufacturing the same. The importance of the Chemical Mechanical Polishing (CMP) process is continuously increasing due to the rise in semiconductor chip integration density and the miniaturization of semiconductor circuits. Precision is critical for enhancing the performance and efficiency of semiconductor chips, and the CMP process plays a decisive role among them. Polishing pads, a key auxiliary material for performing the CMP process, play a core role, and maintaining the thickness and uniformity of the top pad is essential to ensure the precision of the semiconductor chip circuits. The technology for measuring the thickness of the top pad during the CMP process plays a crucial role in enhancing process precision, thereby significantly improving process efficiency and stability. Among these methods, interferometric measurement, which calculates film thickness using the interference spectrum of light reflected from the wafer surface, is a widely used technique. To this end, a window is formed on the top pad to allow light transmission, enabling the measurement of light reflected from the wafer surface. Generally, the top pad and the window block are manufactured as a single integrated unit with the same thickness. For example, Korean Patent Registration No. 1203789 discloses a polishing pad in which the thickness of the window block and the top pad are the same. With this structure, if the wear levels of the window block and the top pad differ, a step difference occurs during use, and in most cases, a problem arises where the window is formed too high. In addition, residue generated during polishing accumulates on the window block, which reduces polishing efficiency. Furthermore, scratches occur on the window surface due to friction from the conditioner, and as a result, thickness measurements through the window cannot be accurately performed, leading to frequent situations where the polishing pad must be replaced even though its actual service life remains. Meanwhile, the recent application of multiple windows to polishing pads aims to improve the accuracy of thickness measurement compared to the existing single-window structure. This structure enhances process stability and minimizes measurement errors through the mutually complementary roles of each window. Furthermore, since the three windows are separated, scratches or damage that may occur on each window can be managed independently, contributing to extending the overall lifespan of the polishing pad. This improves process stability and efficiency, maintains polishing quality, and contributes to reducing production costs. FIG. 1 shows a window arrangement structure of a polishing pad according to one embodiment. Figure 2 shows a window arrangement structure of a polishing pad according to the prior art. FIG. 3 shows a method of inserting a window block into a polishing pad according to one embodiment. FIG. 4 shows a plan view of a polishing pad according to one embodiment. Figure 5 is a photograph of the window (thickness 1.5 mm) area after leakage evaluation in Test Example 1. Figure 6 is a photograph of the window area (thickness 1.3 mm) after the leakage evaluation in Test Example 1. Figure 7 shows the initial transmittance spectrum prior to CMP measured in Test Example 2. Figure 8 shows the final transmittance spectrum after CMP measured in Test Example 2. In describing the embodiments below, detailed descriptions of related known configurations or functions are omitted if it is determined that such descriptions could obscure the essence of the embodiments. Additionally, the sizes of each component in the drawings may be exaggerated or omitted for illustrative purposes and may differ from the actual sizes applied. In this specification, the description that one component is formed above or below another component, or is connected or coupled to one another, includes both direct formation, connection, or coupling between these components and indirect formation, connection, or coupling through the interposition of another component. Furthermore, it should be understood that the criteria for the "above" and "below" of each component may vary depending on the direction in which the object is observed. In this specification, terms referring to each component are used to distinguish them from other components and are not intended to limit the embodiments. Additionally, in this specification, singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as "first," "second," etc. are used to describe various components, and said components should not be limited by said terms. These terms are used for the purpose of distinguishing one component from another. In this spe