Inkjet Adhesive for Semiconductor Bonding
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Solution Overview
Problem
Conventional adhesives used in semiconductor manufacturing face challenges such as void generation, reduced adhesiveness, and reliability issues, especially when dealing with substrates having height differences in wiring patterns, leading to defects and reduced yield in semiconductor devices.
Innovation Solution
An inkjet adhesive comprising a photocurable compound, a photo-radical initiator, a thermosetting compound with cyclic ether or cyclic thioether groups, and a compound capable of reacting with the thermosetting compound, including aromatic amine, which is applied using an inkjet device, cured by light irradiation, and then thermally cured to form a B-staged adhesive layer, suppressing voids and enhancing adhesiveness and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If paste-like adhesive is used for joining semiconductor elements, then adhesive application is simple, but the adhesive spreads causing protrusion and thickness control is difficult
Solution Approach 1:
The patent replaces paste-like adhesive application with inkjet adhesive application. The inkjet method uses a deposition head to precisely deposit adhesive material drop by drop at predetermined positions, replacing the mechanical spreading process with a controlled deposition process that eliminates protrusion and enables precise thickness control.
Solution Approach 2:
The patent changes the physical state of the adhesive from paste-like to inkjet-applicable viscosity. The adhesive composition is modified to have specific viscosity characteristics that enable precise deposition through the inkjet head while maintaining proper adhesion properties for semiconductor element bonding.
2Manufacturing precision
If adhesive sheet with film-like adhesive layer is used, then thickness control is improved, but the adhesive sheet clings to cutting blade during dicing causing chip defects
Solution Approach 1:
The patent replaces the adhesive sheet process with direct inkjet deposition of adhesive onto the semiconductor element. This eliminates the dicing step entirely, removing the problem of adhesive sheets clinging to cutting blades and causing chip defects, while maintaining precise thickness control through controlled deposition.
3Ease of manufacture
If conventional adhesive is used on substrate with height difference of wiring pattern, then application is straightforward, but voids easily remain in height difference portion reducing reliability
Solution Approach 1:
The patent applies adhesive locally at predetermined positions using the inkjet deposition head rather than uniformly across the entire substrate. This localized application ensures adhesive is deposited only where needed, filling height difference portions and eliminating void formation while maintaining a simple application process.
Solution Approach 2:
The patent replaces conventional adhesive application methods with inkjet deposition that can precisely target and fill height difference portions of the wiring pattern. The controlled deposition process ensures complete filling of uneven surfaces without leaving voids, significantly improving bonding reliability.
4Ease of manufacture
If conventional adhesive is used, then initial bonding is achieved, but adhesiveness becomes low when exposed to extreme conditions such as high temperature or high humidity
Solution Approach 1:
The patent uses a composite adhesive composition containing multiple functional components: polyol, isocyanate compound, silane-modified epoxy resin, and inorganic filler. This composite formulation provides both initial bonding capability and enhanced resistance to extreme conditions including high temperature and high humidity, maintaining adhesiveness where conventional adhesives fail.
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
The inkjet adhesive effectively prevents void formation, improves adhesiveness, and enhances moisture-resistant and thermal cycling reliability, ensuring higher accuracy in adhesive layer thickness and improved semiconductor device performance.
Implementation Method 1
an inkjet adhesive comprising a photocurable compound, a photo-radical initiator
Implementation Method 2
a thermosetting compound having one or more cyclic ether groups or cyclic thioether groups, and a compound capable of reacting with the thermosetting compound, including aromatic amine
Data Source
AI summary
Provided is an inkjet adhesive which is applied using an inkjet device, wherein the adhesive can suppress generation of voids in the adhesive layer and, after bonding, can enhance adhesiveness, moisture-resistant adhesion reliability, and cooling/heating cycle reliability. An inkjet adhesive according to the present invention comprises a photocurable compound, a photo-radical initiator, a thermosetting compound having one or more cyclic ether groups or cyclic thioether groups, and a compound capable of reacting with the thermosetting compound, and the compound capable of reacting with the thermosetting compound contains aromatic amine.