NCF Viscosity Maps for Semiconductor Chip Bonding
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Solution Overview
Problem
The challenge in semiconductor chip bonding is setting appropriate heating conditions quickly, as the curing of non-conductive films (NCFs) varies significantly with heating rate and start temperature, leading to potential distortion of the alloy shape and improper joining due to delayed curing and premature melting of metal bumps.
Innovation Solution
A method using a viscosity characteristic map and heating start temperature characteristic map to determine optimal heating conditions by measuring the NCF's viscosity changes with temperature, allowing for precise setting of heating start temperature and rate of temperature increase, ensuring the NCF's viscosity is above curing viscosity before the metal bump melts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If bonding tests are conducted by changing various parameters such as heating rate or heating start temperature to determine heating conditions, then accurate heating conditions can be determined, but it takes a long time to set conditions for bonding
Solution Approach 1:
The patent creates viscosity characteristic maps and heating start temperature characteristic maps in advance through preliminary measurements at various heating rates and start temperatures. These pre-established maps allow operators to quickly determine appropriate heating conditions by simply referencing the maps rather than conducting time-consuming bonding tests for each parameter combination, thus resolving the contradiction between measurement accuracy and time consumption
Solution Approach 2:
The patent creates visual representation maps (viscosity characteristic maps and heating start temperature characteristic maps) that copy and represent the complex relationship between heating parameters and NCF viscosity changes. These maps serve as simplified models that enable quick visual determination of heating conditions without requiring actual bonding tests, thereby reducing time while maintaining accuracy
2Ease of operation
If the NCF is softened before the metal bump is melted, then the NCF can enter the gap between the semiconductor chip and substrate, but the melted metal bump flows and the alloy shape is distorted
Solution Approach 1:
The patent determines the appropriate heating start temperature by referencing the viscosity characteristic maps that show how NCF viscosity changes with temperature at different heating rates. By selecting heating parameters that keep NCF viscosity above the curing viscosity threshold until after metal bump melting is complete, the patent prevents premature softening while still allowing NCF to flow into gaps at the appropriate time, thus resolving the contradiction between ease of operation and manufacturing precision
Solution Approach 2:
The patent replaces physical bonding tests with a theoretical framework based on viscosity characteristic maps. By using these maps to predict NCF behavior under different heating conditions, the patent can determine optimal heating parameters without actually performing trial bonding operations, thereby preventing alloy shape distortion while ensuring proper NCF flow
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 enables efficient and rapid setting of heating conditions for semiconductor chip bonding, ensuring proper alignment and curing of NCFs with the substrate, thereby preventing distortion and ensuring effective chip-substrate joining.
Implementation Method 1
When the semiconductor chip is heated, the NCF is softened before the metal bump is melted
Implementation Method 2
the metal bump is melted to form an alloy between the electrode and an electrode of a substrate
Implementation Method 3
starts to be cured with heat when the temperature further increases
Data Source
AI summary
Provided is a method for setting the conditions for heating a semiconductor chip during bonding of the semiconductor chip using an NCF, wherein a heating start temperature and a rate of temperature increase are set on the basis of a viscosity characteristic map that indicates changes in viscosity with respect to temperature of the NCF at various rates of temperature increase and a heating start temperature characteristic map that indicates changes in viscosity with respect to temperature of the NCF when the heating start temperature is changed at the same rate of temperature increase.