LCoS Panel Wafer-Level Packaging Using TSV Backside Interconnects
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Solution Overview
Problem
Current LCoS panel production lacks a complete wafer level packaging production line, requiring costly equipment customization or transformation, and involves inefficient processes that lead to reduced yield and increased costs due to the need for constant transportation and integration of circuit and liquid crystal packaging steps.
Innovation Solution
The method involves using through-silicon via (TSV) technology to separate circuit and liquid crystal packaging into independent wafer-level processes, allowing for the creation of LCoS panels with vias extending through the silicon substrate, enabling independent packaging and reducing the need for additional packaging on the front side, thus enabling cost control and improved production planning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If equipment customization or transformation is performed to build a complete LCoS wafer level packaging production line, then the production capability is improved, but the equipment cost increases very high
Solution Approach 1:
The patent divides the LCoS panel manufacturing process into two independent wafer-level packaging processes: circuit packaging (using TSV technology) and liquid crystal packaging. This segmentation allows each process to be performed independently on separate production lines without requiring expensive equipment customization or transformation, as each can use existing mature wafer-level packaging capabilities.
2Ease of manufacture
If circuit packaging and liquid crystal packaging are performed in sequence with constant transportation between factories/workshops/equipment, then the packaging is completed, but the yield is reduced and time is lost
Solution Approach 1:
The patent merges the circuit packaging and liquid crystal packaging processes into a single integrated wafer-level manufacturing flow. The TSV technology enables both packaging operations to be performed on the same wafer substrate in sequence without removal, eliminating transportation between different facilities and improving both yield and production efficiency.
3Reliability
If additional circuit packaging is performed on the front side during liquid crystal packaging, then the circuit connections are ensured, but the process complexity increases and damage risk rises
Solution Approach 1:
The patent performs circuit packaging using TSV technology before liquid crystal packaging. The through-silicon vias are formed and conductive interfaces are created on the back surface prior to liquid crystal encapsulation. This preliminary action ensures reliable circuit connections are established before the liquid crystal packaging process begins, eliminating the need for additional circuit packaging operations on the front side and reducing overall process complexity.
Data Source
AI summary
An LCoS panel and a method of preparation includes wafer level packaging, manufacturing vias through a silicon substrate in each die area of a wafer substrate, and manufacturing conductive interfaces on a back surface of the wafer substrate. Each conductive interface corresponds to one via and so connected to an active circuit of the die area where the conductive interface is located. Liquid crystal packaging is applied, a seal coated to surround the pixel circuit area of the active circuit on a front surface of the wafer substrate, injecting liquid crystal into a space defined by the seal, the seal coupling glass substrate comprising a transparent conductive layer and the wafer substrate, and then cutting. Wafer level chip scale packaging of the LCoS panels is thus achieved, the cost is reduced, the obtained LCoS panels are small in total area and of greater thinness.