Underfill Material Copolymerization for Voidless Mounting
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Solution Overview
Problem
Conventional semiconductor chip mounting methods face challenges in achieving low-pressure and voidless mounting, with existing underfill materials often requiring high pressing forces and risking chip warping or solder flow during the process.
Innovation Solution
An underfill material comprising an acrylic polymer, an acrylic monomer, and a maleimide compound, with specific mass ratios and molecular weight ranges, which forms a copolymer upon heating or UV irradiation, providing excellent heat resistance and adhesion, allowing for low-pressure mounting and voidless attachment of semiconductor chips to circuit boards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional underfill materials are used for semiconductor chip mounting, then adhesion is achieved, but high pressing force is required causing chip warping or solder flow
Solution Approach 1:
The patent changes the chemical composition parameters of the underfill material by incorporating specific ratios of acrylic polymer (10-60 parts), acrylic monomer (10-60 parts), and maleimide compound (20-70 parts). This compositional parameter change enables the material to achieve adequate adhesion at lower pressing forces, resolving the contradiction between adhesion strength and pressing force requirements
Solution Approach 2:
The patent creates a composite underfill material system combining acrylic polymer, acrylic monomer, and maleimide compound. This composite formulation synergistically provides both adhesion capability and low-pressing-force characteristics, eliminating the need to choose between strong adhesion and low pressing force
2Reliability
If high pressing force is applied during mounting, then adhesion is ensured, but chip warping and solder flow occur
Solution Approach 1:
The patent modifies the rheological and chemical parameters of the underfill material through specific compositional ratios and molecular weight control (Mw: 100,000-1,200,000). These parameter changes enable the material to provide reliable adhesion while flowing easily at low pressures, preventing chip warping and solder flow that occur with conventional high-pressure mounting
3Productivity
If conventional underfill materials are used, then mounting is achieved, but bubbles are formed during curing
Solution Approach 1:
The patent changes the viscosity and curing characteristics of the underfill material through its specific compositional parameters. The material maintains low viscosity for easy application and bubble-free filling, then cures to form a voidless, reliable bond, achieving both high productivity and manufacturing precision
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 solution enables fluidization of the underfill material with minimal pressing force, prevents bubble formation during curing, and ensures stable, long-term adhesion without chip peeling, reducing warping and solder flow issues while accommodating increased pin counts.
Implementation Method 1
forms a copolymer upon heating or UV irradiation
Implementation Method 2
forms a copolymer upon heating or UV irradiation
Data Source
AI summary
Provided are an underfill material capable of realizing low-pressure mounting and voidless mounting, and a method for manufacturing a semiconductor device using the same. The underfill material includes a main composition containing an acrylic polymer, an acrylic monomer, and a maleimide compound, and the acrylic polymer is contained in a range of 10 parts by mass or more and 60 parts by mass or less in 100 parts by mass of the main composition, and the maleimide compound is contained in a range of 20 parts by mass or more and 70 parts by mass or less in 100 parts by mass of the main composition. Low-pressure mounting and the voidless mounting can be realized.