Die Bonding Temperature Matching to Prevent Die Warping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional die-bonding methods result in die bending due to differing thermal expansion coefficients between substrates and glass carriers, leading to warping and residual internal stress.
Innovation Solution
A die-bonding method that controls the temperature of the substrate and glass carrier based on their thermal expansion coefficients, maintaining equal length during heating and cooling by using light-transmissible devices and controlled heating sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the heating temperature exceeds the melting point of solder balls to ensure proper bonding, then the solder balls melt and penetrate into the substrate for complete fixation, but the difference in thermal expansion between substrate and glass carrier causes die warping
Solution Approach 1:
The patent applies parameter changes by controlling the heating temperature to not exceed the melting point of the solder balls. This temperature parameter control ensures the solder balls melt sufficiently for bonding while limiting thermal expansion differences between substrate and glass carrier, thereby preventing die warping during the bonding process
Solution Approach 2:
The patent addresses thermal expansion by recognizing that the substrate and glass carrier have different thermal expansion coefficients. By controlling the heating temperature within a specific range (not exceeding solder melting point), the patent minimizes the differential thermal expansion that would otherwise cause die warping, while still achieving adequate solder melting for bonding
2Productivity
If high heating temperature is used to melt solder balls quickly, then bonding efficiency is improved, but residual internal stress increases causing die bending
Solution Approach 1:
The patent applies parameter changes by optimizing the heating temperature parameter to a specific range that does not exceed the solder ball melting point. This controlled temperature parameter enables sufficient solder melting for bonding (maintaining productivity) while minimizing excessive thermal stress that would cause die bending (reducing residual internal stress)
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
Prevents die bending and residual stress by ensuring the substrate and glass carrier maintain equal length throughout the heating and cooling processes, enhancing welding efficiency and die stability.
Implementation Method 1
the heating carrier plate heats the substrate, and the substrate transfers the heat to the solder balls
Implementation Method 2
because the thermal expansion coefficients of the substrate and the glass carrier are different and the heating temperature of the heating carrier and the heating temperature of the die-bonding device exceed the melting point of the solder balls
Implementation Method 3
a light source projecting a light passing through the die-bonding device and the glass carrier to heat up the circuit layer
Data Source
AI summary
A method for preventing die from bending is provided, including: disposing a plurality of solder balls between a circuit layer and a substrate; preheating the substrate and the glass carrier respectively with a temperature lower than the melting point of the solder balls; one of the substrate and the glass carrier being made of a first material, and the other made of a second material; the first material having a coefficient of thermal expansion less than the second material and a temperature higher than the second material, so that the substrate and the glass carrier remaining equal length during heating; heating the solder balls by a light source with a temperature higher than the melting point of the solder balls; and after solidifying the solder balls, fastening the circuit layer on the substrate, and the substrate and the glass carrier remaining equal length during cooling.