Rigid-Flexible Stamp Structure for Precision Semiconductor Transfer
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Solution Overview
Problem
Existing methods for transferring single crystalline silicon or Group III-V compound semiconductor microribbons without an adhesion layer face challenges in controlling uniform desorption rates and shape over large substrates, leading to reduced alignment accuracy and scalability issues due to the viscoelastic properties of PDMS stamps and thermal expansion methods.
Innovation Solution
A stamp structure with a rigid frame and patterned holes, including cylindrical and slit-shaped holes, is used to transfer objects by vacuum pressing and air injection through holes, allowing for precise alignment and transfer without deformation, using materials like PMMS, PC, PU, and metal, and featuring a flexible membrane for independent hole operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a PDMS stamp with viscoelastic properties is used for transferring single crystalline ribbons, then the bonding force between the ribbon and stamp can be controlled through desorption rate, but the alignment accuracy is reduced during transferring due to shape change of the stamp when the substrate is enlarged
Solution Approach 1:
The stamp is segmented into a rigid frame portion and a flexible membrane portion. The rigid frame maintains overall shape stability and alignment accuracy, while the flexible membrane locally adapts to control bonding force through desorption rate. This segmentation resolves the contradiction by separating the functions of shape stability and bonding control.
Solution Approach 2:
Different portions of the stamp have different mechanical properties: the frame portion is rigid for structural stability, while the membrane portion is flexible for local bonding control. The holes are selectively positioned in the membrane to enable localized adhesion control without compromising overall alignment accuracy.
2Productivity
If the substrate and apparatus are enlarged to manufacture larger scale substrates, then productivity is improved, but it becomes difficult to control the uniform desorption rate and shape over the entire area, reducing alignment accuracy
Solution Approach 1:
The stamp structure divides the large substrate area into regions supported by the rigid frame, which maintains shape stability across the entire large area. The flexible membrane with selectively positioned holes enables uniform desorption control across the enlarged substrate without compromising alignment accuracy.
Solution Approach 2:
The patent replaces the traditional fully flexible PDMS stamp with a hybrid rigid-flexible structure. The rigid frame provides mechanical stability for large-scale substrates, while the flexible membrane with controlled hole distribution maintains the necessary adhesion control, enabling scalable manufacturing with preserved precision.
3Productivity
If laser driven transfer printing (LDTP) method is used to transfer the ribbon by irradiating pulsed laser to the interface, then thermal expansion difference causes transfer, but alignment accuracy is further reduced during transferring
Solution Approach 1:
The rigid frame portion of the stamp does not undergo thermal expansion during laser irradiation, maintaining structural stability and alignment accuracy. The flexible membrane portion can locally accommodate thermal effects while the overall stamp shape remains stable, resolving the contradiction between transfer efficiency and alignment precision.
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 improves alignment accuracy and scalability by maintaining stamp structure integrity during transfer, enabling efficient transfer of functional materials like single crystalline Si and Group III-V compound semiconductors to larger substrates with high precision and without the need for adhesive layers.
Implementation Method 1
a suction hole array which respectively face a plurality of objects formed on a donor substrate, thereby the objects may be pressed tightly to the stamp structure by vacuum inhalation
Implementation Method 2
a blowing hole array which respectively correspond to the suction hole array, thereby the object may be desorbed from the stamp structure by air pressing
Data Source
Figure 1~2A
Figure 2B~2C
Figure 2D~2F
AI summary
A stamp structure includes a stamp frame having a plate part. The plate part includes a plurality of holes. The plurality of holes are configured to facilitate the adsorption of an object to the plate part during a transfer of the object from a donor substrate to a target substrate.