Chip Bonding Apparatus with Segmented Thermal Process
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Solution Overview
Problem
The high-temperature thermo-compression process in chip bonding can cause flexural deformation of integrated circuit chips, leading to partial contact with anisotropic conductive films and deteriorated electrical connections.
Innovation Solution
A chip bonding apparatus and method that involves heating the anisotropic conductive film to a high temperature and then using a bonding head at a lower temperature to thermo-compress the integrated circuit chip onto a substrate, with the substrate, film, and chip laminated successively on a stage, breaking the insulator surrounding the conductive balls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature thermo-compression is applied to break the insulator and achieve electrical connection, then electrical connectivity is improved, but flexural deformation of the integrated circuit chip occurs
Solution Approach 1:
The bonding process is divided into two separate stages: first heating the anisotropic conductive film to a high temperature (250-350°C) to break the insulator, then performing compression at a lower temperature (below 100°C) to avoid chip deformation. This segmentation of the thermal process allows achieving electrical connectivity without causing flexural deformation to the integrated circuit chip.
Solution Approach 2:
The anisotropic conductive film is pre-heated to a high temperature before the integrated circuit chip is compressed onto it. This preliminary heating action breaks the insulator surrounding the conductive balls in advance, so that when the chip is compressed at a lower temperature, electrical connection is already established without requiring high-temperature compression that would cause chip deformation.
2Shape
If the bonding head temperature is reduced to prevent chip deformation, then chip shape stability is improved, but the insulator breaking efficiency decreases
Solution Approach 1:
The thermal process is segmented into two distinct phases: a pre-heating phase where the anisotropic conductive film is heated to 250-350°C to break the insulator, and a compression phase where the chip is pressed at a lower temperature (below 100°C) to maintain shape stability. This segmentation allows each phase to optimize for its specific function without compromising the other.
Solution Approach 2:
The anisotropic conductive film serves as an intermediary that absorbs the high-temperature heating action separately from the chip compression action. By pre-heating the film to break the insulator before compression, the film mediates between the need for high temperature (for insulator breaking) and low temperature (for chip shape stability).
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 flexural deformation and partial contact of chip bumps with the conductive film, enhancing the reliability of electrical connections between the chip and substrate.
Implementation Method 1
heating an anisotropic conductive film at a first temperature using a heating unit
Implementation Method 2
breaking the insulator that surrounds the conductive ball included in an anisotropic conductive film
Implementation Method 3
bonding the integrated circuit chip that is attached to the anisotropic conductive film onto the substrate through thermo-compression of the integrated circuit chip onto the substrate at a second temperature that is lower than the first temperature
Implementation Method 4
attaching an integrated circuit chip to the anisotropic conductive film using an attachment unit
Data Source
AI summary
The chip bonding apparatus used in a chip bonding method includes a heating unit for heating an anisotropic conductive film at a first temperature; an attachment unit for attaching an integrated circuit chip to the anisotropic conductive film; a stage on which a substrate is seated; a chip transport unit for moving and aligning the integrated circuit chip that is attached to the anisotropic conductive film on the substrate; and a bonding head arranged above the stage to bond the integrated circuit chip that is attached to the anisotropic conductive film onto the substrate through thermo-compression of the integrated circuit chip onto the substrate at a second temperature that is lower than the first temperature.