Polishing Pad Temperature Control for CMP Profile Stability
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Solution Overview
Problem
In semiconductor device manufacturing, the increasing number of interconnection layers leads to poor step coverage and surface irregularities, requiring improved planarization techniques to maintain a stable polishing rate and prevent concave profiles during chemical mechanical polishing (CMP).
Innovation Solution
A polishing method and apparatus that adjust the surface temperature of the polishing pad by heating or cooling specific areas using a pad contact member, ensuring a constant temperature change profile to control the polishing rate and profile without measuring film thickness, by calculating and normalizing heat profiles across the pad.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pad contact member is designed to have the largest possible contact area to quickly raise the surface temperature of the polishing pad, then the polishing rate is increased, but the temperature distribution becomes uneven causing concave polishing profile
Solution Approach 1:
The polishing pad surface is divided into multiple temperature zones (first, second, and third regions) with different temperature control characteristics. Each region can be independently heated or cooled to achieve uniform temperature distribution across the pad surface, preventing the concave profile while maintaining high polishing rate.
Solution Approach 2:
The pad contact member is segmented into multiple independent heating/cooling regions that correspond to different areas of the polishing pad. This segmentation allows for localized temperature control in each region, enabling the system to raise the overall pad temperature quickly while maintaining uniform temperature distribution to prevent concave polishing profile.
2Productivity
If the surface temperature of the polishing pad is raised quickly to increase polishing rate, then productivity increases, but the temperature history of the substrate changes causing deviation from target profile
Solution Approach 1:
The system dynamically adjusts temperature parameters across different regions of the polishing pad during the polishing process. By changing the temperature distribution pattern from uniform to differentiated (with cooler central regions and warmer outer regions), the system maintains stable substrate temperature history while achieving high polishing rates.
Solution Approach 2:
The polishing apparatus incorporates temperature sensors and control systems that monitor the temperature history of the substrate in real-time. This feedback mechanism allows the system to adjust the heating/cooling rates in different pad regions to maintain the desired temperature history, ensuring consistent polishing profile while maximizing productivity.
3Manufacturing precision
If a pad contact member is introduced to control temperature distribution, then polishing profile control is improved, but device complexity increases
Solution Approach 1:
The pad contact member serves multiple functions: it acts as both a mechanical support structure and an integrated heating/cooling system. The same component that contacts the polishing pad to apply pressure also contains the temperature control elements, eliminating the need for separate heating/cooling devices and reducing overall system complexity.
Solution Approach 2:
The heating and cooling systems are merged into a single pad contact member structure. The temperature control elements are integrated within the contact member itself, combining the mechanical function of pad contact with the thermal management function in one unified component, thereby simplifying the device architecture.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for controlled polishing profiles and increased polishing rates while maintaining a stable substrate temperature history, preventing over-polishing and achieving profiles similar to those without a pad contact member.
Implementation Method 1
adjusting a surface temperature of the polishing pad by heating or cooling specific areas using a pad contact member
Implementation Method 2
the surface of the substrate is planarized by a chemical action of the polishing liquid and a mechanical action of the abrasive particles contained in the polishing liquid
Implementation Method 3
the surface of the substrate is planarized by a chemical action of the polishing liquid and a mechanical action of the abrasive particles contained in the polishing liquid
Data Source
AI summary
A polishing method and a polishing apparatus which can increase a polishing rate and can control a polishing profile of a substrate being polished by adjusting a surface temperature of a polishing pad are disclosed. The polishing method for polishing a substrate by pressing the substrate against a polishing pad on a polishing table includes a pad temperature adjustment step of adjusting a surface temperature of the polishing pad, and a polishing step of polishing the substrate by pressing the substrate against the polishing pad having the adjusted surface temperature. In the pad temperature adjustment step, the surface temperature of a part of an area of the polishing pad, the area being to be brought in contact with the substrate, is adjusted during the polishing step so that the rate of temperature change of a temperature profile in a radial direction of the surface of the polishing pad becomes constant in the radial direction of the polishing pad.