Semiconductor Substrate Crystal Orientation for Crack Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor crystals are prone to cracking during mechanical processing due to their high brittleness and anisotropic mechanical properties, leading to waste and reduced yield, as existing methods fail to account for crystallographic orientation and distribute mechanical forces effectively across cleavage planes.
Innovation Solution
The crystal structure of semiconductor semi-finished products or substrates is oriented such that crystallographic axes associated with cleavage planes are tilted relative to the central axis, distributing radial mechanical forces over a predetermined minimum number of parallel cleavage planes, reducing the force per plane and minimizing cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical processing is performed on semiconductor crystals, then substrates can be produced, but cracking occurs along cleavage planes due to high brittleness and anisotropic mechanical properties
Solution Approach 1:
The patent changes the crystallographic orientation parameters of the semiconductor substrate. Specifically, it uses off-axis oriented substrates where the crystallographic c-axis is tilted by a specific angle (e.g., 4 degrees) relative to the substrate normal, and the a-axis is rotated by a specific angle (e.g., 30 degrees) relative to the radial direction. This parameter change in crystal orientation distributes mechanical stresses across multiple cleavage planes during processing, preventing crack propagation along single planes and thereby improving reliability while maintaining productivity
2Ease of manufacture
If radial forces are applied during mechanical processing, then material can be removed and shaped, but the force concentrates on fewer cleavage planes increasing crack probability
Solution Approach 1:
The patent modifies the geometric parameters of force distribution by changing crystal orientation. The off-axis orientation (c-axis tilt and a-axis rotation) transforms the stress distribution pattern during radial mechanical processing, causing forces to be distributed across multiple cleavage planes rather than concentrated on fewer planes, thus reducing cracking susceptibility while maintaining ease of manufacture
Solution Approach 2:
The patent introduces asymmetry in crystal orientation relative to the processing geometry. By tilting the c-axis and rotating the a-axis at specific asymmetric angles, the symmetric stress distribution that would concentrate force on aligned cleavage planes is broken, distributing the mechanical load more evenly across multiple planes and reducing crack risk during radial processing
3Productivity
If crystal orientation is optimized for crack reduction, then yield improves, but processing parameters and setup complexity increase
Solution Approach 1:
The patent applies preliminary action by pre-orienting the crystal structure during substrate preparation before mechanical processing. The off-axis orientation is established in advance, so that when standard radial mechanical processing is subsequently applied, the forces are automatically distributed across multiple cleavage planes without requiring modified processing equipment or complex real-time adjustments, thus improving yield without significantly increasing processing setup complexity
Data Source
AI summary
Crystal structure orientation in semiconductor semi-finished products and semiconductor substrates for fissure reduction and method of setting same The present invention provides monocrystalline semiconductor semi-finished product and substrates having a predetermined orientation of its crystal structure relative to a central axis and a at least partially curved lateral surface of the semi-finished product or substrate that reduces or even eliminates the occurrence of cracks during mechanical processing, and a method of producing such semiconductor semi-finished products and/or substrates. In the predetermined orientation, a first crystallographic axis perpendicular to a set of first cleavage planes makes a first tilt angle with a plane transverse to the central axis, and a second crystallographic axis perpendicular to a set of second cleavage planes and to the first crystallographic axis makes a second tilt angle with said plane transverse to the central axis so that each set of parallel cleavage planes that are symmetrically equivalent to either the first or second cleavage planes are inclined relative to the central axis.