Quartz Susceptor Pillar Support for Thermal Stress Relief
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Solution Overview
Problem
Conventional semiconductor manufacturing devices using aluminum nitride susceptors contaminate wafers with aluminum impurities and suffer from thermal stress and structural damage due to differences in thermal expansion coefficients and pressure differentials between high-melting-point electrodes and quartz susceptors.
Innovation Solution
A semiconductor manufacturing device with a susceptor having a main body made of quartz and a high-frequency electrode with a gap between the electrode and the susceptor walls, supported by pillars to absorb thermal expansion differentials and reinforce structural integrity, preventing contamination and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the susceptor is made from aluminum nitride, then the susceptor can withstand high processing temperatures, but the wafer becomes contaminated with aluminum impurities
Solution Approach 1:
The susceptor is divided into two distinct parts: a main body made of aluminum nitride for thermal resistance, and a wafer-contacting surface made of quartz for contamination prevention. This segmentation allows each part to perform its optimal function without compromising the other.
Solution Approach 2:
A quartz layer is introduced as an intermediary between the aluminum nitride main body and the wafer. This intermediate layer prevents direct contact between the wafer and aluminum-containing materials, thereby preventing contamination while maintaining thermal performance.
2Object-affected harmful factors
If the susceptor surface for supporting the wafer is formed from quartz, then wafer contamination is prevented, but the difference in thermal expansion coefficients between the high-frequency electrode and quartz causes stress that damages the electrode
Solution Approach 1:
Gaps are intentionally designed between the high-frequency electrode and the quartz susceptor surface to cushion and absorb thermal expansion differences. This preemptive design prevents stress buildup that would otherwise damage the electrode during thermal cycling.
Solution Approach 2:
The physical configuration is changed by introducing gaps between components, transforming the system from a rigid bonded structure to a flexible spaced structure that can accommodate thermal expansion variations without transmitting stress.
3Stability of the object's composition
If the quartz member thickness is set to approximately 1.5 millimeters, then the susceptor structure is stable, but the quartz material is damaged due to the pressure differential between atmospheric pressure and processing pressure
Solution Approach 1:
The susceptor structure is segmented to include multiple support points (pillars) that distribute the pressure differential loads. This segmentation reduces the stress concentration on any single quartz component, preventing damage while maintaining overall structural stability.
4Ease of operation
If the distance from the wafer rear surface to the high-frequency electrode is short, then bias voltage application is improved, but the thermal expansion differential causes stress that damages the electrode
Solution Approach 1:
The spatial arrangement is optimized by maintaining a short functional distance for electrical performance while introducing gaps at stress-prone interfaces. This parameter optimization allows simultaneous achievement of good electrical contact and mechanical stress relief.
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
Prevents contamination of wafers, reduces thermal stress on high-frequency electrodes, and enhances processing efficiency by maintaining a uniform voltage distribution and allowing higher processing temperatures, thus improving the yield and speed of IC manufacturing.
Implementation Method 1
the difference in thermal expansion coefficients between the high melting point material of the high-frequency electrode and the quartz of the susceptor causes stress that damages the lattice-shaped high-frequency electrode
Implementation Method 2
a high-frequency electrode for applying a bias voltage
Implementation Method 3
A magnetic field is formed by supplying high-frequency electrical power to the cylindrical electrode to induce magnetron discharge
Implementation Method 4
electrons discharged from the cylindrical electrode rotate in a continual cycloid movement while drifting, the ionization rate is boosted due to a longer electron life and high-density plasma is generated
Implementation Method 5
Reactive gas is supplied into the processing chamber via a shower plate
Implementation Method 6
the susceptor sometimes contains a heater for heating the wafer
Data Source
AI summary
Wafer contamination is prevented, while preventing damage to a high-frequency electrode and a susceptor. A main body 41 of the susceptor 40 of an MMT apparatus is composed of a heater arranging plate 42, an electrode arranging plate 48, and a supporting plate 56 all made from quartz. A circular electrode arranging hole 49 with a fixed depth is concentrically formed on the upper surface of the electrode arranging plate 48, and quadrangular pillars 50 are formed protruding in a matrix on the bottom of the electrode arranging hole 49. Multiple insertion holes 52 are formed in a disk-shaped high-frequency electrode 51, and the high-frequency electrode 51 is installed in the electrode arranging hole 49 by inserting each pillar 50 into each insertion hole 52. The gaps Sa and Sb are provided between the high-frequency electrode 51 and the electrode arranging plate 48. The pillar 50 boosts the strength of the electrode arranging plate 48. Damage to the high-frequency electrode is prevented even if the thermal expansion coefficient of the high-frequency electrode is larger than that of the electrode arranging plate, since the gaps absorb the thermal expansion differential.