Wire Saw Thermal Compensation for Slice Flatness and Parallelism
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Solution Overview
Problem
Existing methods for cutting multiple slices using a wire saw struggle to achieve high flatness and plane parallelism, especially in the semiconductor industry, due to limited effectiveness of previous measures and increasing demands for precision.
Innovation Solution
The method involves a wire saw with a wire array of moving wire sections and an actuating device, where the wire array is tensioned between two wire guide rollers with adjustable temperature chambers and bearings. During cut-off operations, the temperature of the chambers and bearings is adjusted according to specific temperature profiles to change the length of the shell and move the floating bearings, thereby correcting shape deviations and improving slice quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional wire saws with fixed and floating bearings are used, then the structure is simple and easy to manufacture, but the flatness and plane parallelism of cut slices deteriorate due to temperature-induced wire array displacement
Solution Approach 1:
The wire guide roller is designed with a dynamic temperature control system where the shell can expand or contract axially in response to temperature changes. The shell is secured to the core in a manner that allows thermal expansion while maintaining structural integrity, enabling the wire array position to be dynamically adjusted to compensate for temperature-induced displacements and maintain slice flatness.
Solution Approach 2:
The invention changes the temperature parameter of the wire guide roller shell to control its axial length. By adjusting the shell temperature, the axial position of the wire array can be modified to counteract temperature-induced displacements. This parameter change approach allows precise control of the wire array position relative to the workpiece, improving slice flatness without requiring complex mechanical adjustment mechanisms.
2Manufacturing precision
If temperature control measures are implemented to counteract wire array displacement, then slice flatness improves, but the system complexity and energy consumption increase
Solution Approach 1:
The temperature control system applies localized heating or cooling specifically to the wire guide roller shell rather than the entire wire saw system. This localized approach allows precise control of shell expansion/contraction to maintain wire array position while minimizing overall energy consumption. The thermal control is applied only where needed to achieve the desired compensation effect.
Solution Approach 2:
The invention replaces complex mechanical adjustment mechanisms with a thermal control system. Instead of using mechanical actuators to physically adjust the wire array position, the system uses temperature control to induce thermal expansion or contraction of the shell, thereby achieving position adjustment. This substitution simplifies the mechanical structure while maintaining precision control.
3Stability of the object's composition
If the shell is fixed with clamping rings to prevent displacement, then structural stability improves, but thermal expansion is restricted causing increased stress and potential damage
Solution Approach 1:
The shell is secured to the core in a manner that allows dynamic thermal expansion and contraction. The connection design enables the shell to change axial length in response to temperature variations without generating excessive stress. This dynamic connection maintains structural stability while accommodating thermal effects, preventing stress concentration and potential damage that would occur with rigid fixed connections.
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 method effectively minimizes shape deviations and improves the flatness and plane parallelism of cut slices, meeting the increasingly demanding requirements of the semiconductor industry by using a combination of wire guide heat control, wire guide temperature control, and ingot positioning control.
Implementation Method 1
changing a length of the shell of each the two wire guide rollers by adjusting a temperature of the chamber of each of the wire guide rollers with a first cooling fluid
Implementation Method 2
axially moving the floating bearings of the two wire guide rollers by adjusting a temperature of the fixed bearings of the wire guide rollers with a second cooling fluid
Implementation Method 3
feeding a respective workpiece of the workpieces through the wire array along a feed direction perpendicular to a workpiece axis and perpendicular to a plane of the wire array in the presence of a working fluid and hard materials, which act abrasively on the workpiece
Data Source
AI summary
A method cuts slices from workpieces using a wire saw having a wire array, which is tensioned in a plane between two wire guide rollers supported between fixed and floating bearings and having a chamber and a shell. The workpiece is fed through the wire array along a feed direction perpendicular to a workpiece axis, while simultaneously changing the shells' lengths by adjusting a temperature of the chambers with a first cooling fluid in accordance with a first correction profile specifying a change in the shells' lengths based on the depth of cut. The floating bearings are simultaneously axially moved by adjusting a temperature of the fixed bearings with a second cooling fluid in accordance with a second correction profile, which specifies a travel of the floating bearings based on the depth of cut. The first correction profile and the second correction profile are opposed to a shape deviation.