AlN Ceramic Substrate Support with Mo Resistors
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Solution Overview
Problem
Semiconductor substrate processing apparatuses face challenges in managing thermal stress and preventing diffusion-induced cracks in ceramic bodies due to temperature variations and element diffusion during high-temperature processes.
Innovation Solution
A substrate support unit with a ceramic body featuring dual-zone heating, molybdenum heat generating resistors, and coating layers of molybdenum aluminum nitride and magnesium-doped aluminum nitride to alleviate thermal stress and prevent diffusion of sintering aid elements like yttrium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a ceramic body is used in substrate processing apparatus, then high-temperature resistance is improved, but thermal stress and crack formation occur due to temperature variations
Solution Approach 1:
The patent applies parameter changes by doping aluminum nitride ceramic with magnesium to create Mg-doped AlN ceramic. This changes the material parameters (compositional parameter) to improve thermal stress resistance while maintaining high-temperature resistance. The magnesium doping modifies the crystal structure and thermal properties of the ceramic, allowing it to withstand temperature variations without cracking.
Solution Approach 2:
The patent uses composite materials by creating a Mg-doped AlN ceramic system. This is a composite material approach where magnesium atoms are incorporated into the aluminum nitride crystal lattice, forming a doped ceramic composite. The combination of AlN base material with Mg dopant creates a composite structure that exhibits both high-temperature resistance and improved crack resistance.
2Ease of manufacture
If sintering aid elements are added to ceramic body, then manufacturing processability is improved, but element diffusion causes cracks during high-temperature processing
Solution Approach 1:
The patent applies parameter changes by controlling the doping concentration of magnesium in the AlN ceramic. By optimizing the Mg doping level, the patent achieves a balance between maintaining sintering processability (which requires some sintering aids) and preventing element diffusion that causes cracks. The specific doping parameter range is controlled to eliminate crack formation while preserving manufacturing feasibility.
3Manufacturing precision
If dual-zone heating is implemented, then temperature control precision is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the substrate support into two distinct heating zones: a first heating zone and a second heating zone. Each zone has its own heat generating resistor, allowing independent temperature control. This segmentation enables precise temperature control for different regions of the substrate while using a relatively simple structure of separate resistive heating elements.
Solution Approach 2:
The patent applies local quality by providing different thermal conditions in different regions of the substrate support. The first and second heating zones can be controlled to different temperatures, allowing local optimization of processing conditions. This enables different areas of the substrate to experience tailored temperature profiles suitable for specific processing requirements.
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
The solution effectively reduces thermal stress and crack formation in ceramic bodies, enhancing the durability and reliability of substrate processing apparatuses by independently controlling temperature zones and preventing element diffusion.
Implementation Method 1
a heat generating resistor disposed in the ceramic body, and including molybdenum (Mo)
Implementation Method 2
an outer coating layer surrounding the first and second inner coating layers, and including aluminum nitride doped with magnesium (Mg)
Data Source
AI summary
A substrate support unit includes: a ceramic body having a surface for supporting a substrate, the ceramic body including aluminum nitride (AlN), a heat generating resistor disposed in the ceramic body, and including molybdenum (Mo), and a coating layer surrounding the heat generating resistor, and including molybdenum aluminum nitride (MoAlN).