Driver IC Film Unit Test Pad Integration for Display Yield
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Solution Overview
Problem
As the resolution and pixel density of electro-luminescence display devices increase, the manufacturing difficulty and cost of the driver IC film unit also rise due to narrower wire intervals and a higher defective bonding rate, particularly because the area required for test pads is substantial, limiting the reduction of pad size and increasing manufacturing costs.
Innovation Solution
The driver IC film unit is designed with a flexible film configuration where test pad units are formed on the same surface as the pads, allowing for inspection and subsequent removal, reducing the overall area occupied by test pads and improving yield, while using multiple metal layers for signal wires to maintain signal integrity and facilitate defect inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the resolution and pixel density of the display device are increased, then the display quality is improved, but the manufacturing difficulty and cost of the driver IC film unit increase due to narrower wire intervals and higher defective bonding rate
Solution Approach 1:
The patent applies preliminary action by forming test pad units on the same surface as the pads before final bonding, allowing defect inspection to be performed in advance. This enables early detection of bonding defects and facilitates rework or replacement before the product reaches the customer, thereby addressing the increased manufacturing difficulty associated with higher resolution displays.
2Difficulty of detecting and measuring
If the area required for test pads is increased to facilitate defect inspection, then the inspection capability is improved, but the overall pad area increases limiting the reduction of pad size and increasing manufacturing costs
Solution Approach 1:
The patent merges the test pad units with the functional pads by forming both on the same surface of the flexible film. This consolidation allows defect inspection functionality to be integrated without requiring separate dedicated test pad areas, thereby maintaining inspection capability while minimizing the overall area occupied by pad structures.
Solution Approach 2:
The test pad units are designed to serve multiple purposes: they function as both test structures for defect inspection and as part of the overall pad structure. This multi-functionality allows the same area to serve dual purposes, reducing the need for additional dedicated test pad space and thereby controlling the overall pad area despite the need for inspection capabilities.
3Reliability
If multiple metal layers are used for signal wires to maintain signal integrity, then the signal quality is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent addresses signal integrity by adding the vertical dimension through multiple metal layers. Instead of increasing wire width or using complex routing patterns in the planar dimension, the solution utilizes stacked metal layers to provide shielded signal paths and reduce interference, thereby maintaining signal quality while controlling structural complexity through vertical integration.
Data Source
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AI summary
A driver IC film unit (110) including a flexible film (106), a driver IC (112) on a first surface of the flexible film (106) and configured to receive an input signal and convert the input signal into an image signal for a display panel (100), at least first to third pad units (120, 122, 124), on the first surface of the flexible film (106), configured to electrically connect the driver IC (112) and the flexible film (106), and at least first to third wire units (140, 142, 144), on the first surface of the flexible film (106), electrically connected to the at least first to third pad units (120, 122, 124), wherein at least one wire unit among the at least first to third wire units (140, 142, 144) is configured to be extended to a second surface facing the first surface via a first via hole (118) passing through the flexible film (106), and is configured to include a cut portion of wire (150) corresponding to an edge of the flexible film (106).