Glass Substrate Via Formation via Laser Alteration Layer
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Solution Overview
Problem
The existing via-first process for forming through glass vias (TGVs) in glass substrates for interposer substrates leads to metal contamination, causing characteristic variation in active elements like TFTs, which is difficult to manage due to the lack of effective washing technologies and high power consumption when trying to absorb the voltage variation, especially in large-sized TFT manufacture lines.
Innovation Solution
A method of manufacturing a wiring substrate with a through glass via that involves forming a patterned alteration layer penetrating the glass substrate, allowing for the formation of connections between the front and back surfaces without initial metal filling, using photosensitive or non-photosensitive glass and selective chemical etching to minimize thermal expansion issues and reduce contamination risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the via-first process is used to form through glass vias (TGVs) in glass substrates, then the manufacturing process consistency is improved, but metal contamination occurs causing characteristic variation in active elements
Solution Approach 1:
The patent applies preliminary action by forming the alteration layer in advance before creating the via holes. The alteration layer is formed by irradiating the glass substrate with laser beams, which modifies the glass structure in the via regions. This preliminary modification enables subsequent easy removal of glass material to form vias, while the layer itself acts as a barrier to prevent metal contamination from reaching the active elements during the via formation and metal filling processes.
2Stability of the object's composition
If heat treatment is performed at softening point temperature to relieve stress on via openings, then the stress relief is achieved, but the temperature exceeds the heat resistance of the wiring process
Solution Approach 1:
The patent extracts the stress relief function from the high-temperature heat treatment process. Instead of heating the entire substrate to the glass softening point, the invention selectively removes the alteration layer material at lower temperatures to form via holes. This extraction of the problematic high-temperature step eliminates the conflict with wiring process heat resistance while still achieving the necessary stress management through the controlled removal of the pre-modified glass layer.
3Manufacturing precision
If a great number of fine vias are formed in glass substrate using sequential laser abrasion, then via formation is achieved, but the processing time period becomes impractically long
Solution Approach 1:
The patent implements continuity of useful action by using continuous or rapidly scanning laser beams to form the alteration layer across the entire glass substrate in a single pass. Instead of sequentially treating each via location individually, the laser continuously irradiates the substrate, creating a comprehensive alteration pattern that covers all future via locations. This continuous action dramatically reduces processing time while maintaining the precision needed for fine via formation, enabling practical manufacturing of substrates with large numbers of vias.
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 approach reduces the influence of metal contamination on active elements, enabling more stable operation and eliminating the need for additional processes like filling and removing substitute materials, while maintaining thermal stability and preventing damage to wirings.
Implementation Method 1
forming an alteration layer that penetrates the wiring substrate and is patterned
Implementation Method 2
by irradiation of a glass substrate with laser beams, an alteration layer is formed
Implementation Method 3
filling an electrode material in a hole formed by removing the alteration layer
Data Source
AI summary
A method of manufacturing a wiring substrate that has a wiring including a through glass via and is formed of a glass substrate includes forming an alteration layer that penetrates the wiring substrate and is patterned, forming the wiring on a front surface of the wiring substrate in which the alteration layer has been formed, and filling an electrode material in a hole formed by removing the alteration layer, thereby forming the through glass via that connects the wiring on the front surface of the wiring substrate and the wiring on a back surface side thereof.