Substrate-Free Semiconductor Chip Production via Sacrificial Layer
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Solution Overview
Problem
Current methods for producing optoelectronic semiconductor chips often require carrier and growth substrates, which limit further chemical or thermal processing and can result in residual contamination and reduced precision due to the use of thermally removable carrier films.
Innovation Solution
A method involving growing a semiconductor layer sequence on a growth substrate, applying metallization, attaching an intermediate carrier with a sacrificial layer, removing the growth substrate, structuring into individual chip regions, and partially dissolving the sacrificial layer to facilitate mechanical separation of the chips from the carrier, allowing for precise and contamination-free processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If carrier films are used to support semiconductor chips during processing, then mechanical stability is improved, but residual contamination and reduced precision occur due to thermal processing limitations
Solution Approach 1:
A sacrificial layer is introduced as an intermediary between the intermediate carrier and the semiconductor layer sequence. This sacrificial layer can be selectively removed by chemical etching, allowing the intermediate carrier to be separated from the semiconductor structure without mechanical force that could cause contamination or damage. The sacrificial layer acts as a temporary mediator that facilitates precise separation while maintaining mechanical stability during processing.
2Reliability
If growth substrates are used to grow semiconductor layers, then crystal quality is improved, but the chips cannot be processed further without residual contamination
Solution Approach 1:
The growth substrate is completely removed from the semiconductor layer sequence after the semiconductor layers are grown. The method enables extraction of the semiconductor layer sequence from the growth substrate while maintaining crystal quality, and the growth substrate is discarded as it serves only its initial purpose of enabling layer growth. This extraction eliminates residual contamination from the growth substrate in the final chip product.
Solution Approach 2:
The growth substrate is treated as a disposable, single-use component. It is used temporarily to grow the semiconductor layers with high crystal quality, then completely removed. The sacrificial layer serves as a temporary intermediary that is also completely removed after serving its purpose of enabling carrier attachment. These temporary components are discarded without remaining in the final product, avoiding contamination.
3Object-generated harmful factors
If the sacrificial layer is completely removed before carrier removal, then cleanliness is improved, but mechanical breaking becomes difficult
Solution Approach 1:
The sacrificial layer is only partially removed by chemical etching, leaving behind discrete islands or remnants distributed across the surface. This partial removal is sufficient to reduce adhesion forces and enable mechanical breaking of the carrier, while the remaining sacrificial layer islands provide friction and grip points that facilitate the mechanical separation process. Complete removal would make mechanical breaking difficult, so partial removal optimizes both cleanliness and manufacturability.
4Manufacturing precision
If strong adhesion between intermediate carrier and semiconductor layer sequence is maintained, then positioning precision is improved, but chip separation becomes difficult
Solution Approach 1:
The adhesion between the intermediate carrier and semiconductor layer sequence is made dynamic rather than static. Initially, strong adhesion (mediated by the sacrificial layer) maintains positioning precision during processing. Then, through selective chemical etching of the sacrificial layer, the adhesion is dynamically reduced to enable easy mechanical separation. The system transitions from a high-adhesion state to a low-adhesion state at different processing stages.
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 enables the production of substrate-free and carrier-free semiconductor chips with reduced adhesion force, allowing for precise manufacturing and avoiding residual contamination, thus enhancing the reliability and precision of optoelectronic semiconductor chip production.
Implementation Method 1
at least partially dissolving the sacrificial layer
Implementation Method 2
removing the intermediate carrier includes mechanically breaking remaining regions of the sacrificial layer
Data Source
AI summary
A method of producing optoelectronic semiconductor chips includes growing a semiconductor layer sequence on a growth substrate; applying at least one metallization to a contact side of the semiconductor layer sequence, which contact side faces away from the growth substrate; attaching an intermediate carrier to the semiconductor layer sequence, wherein a sacrificial layer is attached between the intermediate carrier and the semiconductor layer sequence; removing the growth substrate from the semiconductor layer sequence; structuring the semiconductor layer sequence into individual chip regions; at least partially dissolving the sacrificial layer; and subsequently removing the intermediate carrier, wherein, in removing the intermediate carrier, part of the sacrificial layer is still present, removing the intermediate carrier includes mechanically breaking remaining regions of the sacrificial layer, and the sacrificial layer is completely removed after removing the intermediate carrier.