Flip Chip Bonder Cooling Mechanism for Bonding Time Reduction
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Solution Overview
Problem
In flip chip bonding, the conventional technique of suctioning a chip to a bonding tool with a gap results in significant displacement of the chip's position and direction, leading to lowered bonding quality and increased bonding time due to the need for cooling the bonding tool using air at normal temperatures.
Innovation Solution
A flip chip bonder equipped with a flip mechanism, a bonding tool, and a cooling mechanism that cools the holding member to a predetermined temperature before receiving the chip, allowing for efficient heat transfer and reduced bonding time without compromising quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the bonding tool is cooled using air at normal temperatures, then the bonding tool temperature is reduced below the melting temperature of the non-conductive film, but the bonding time is significantly increased
Solution Approach 1:
A cooling member is introduced as an intermediary between the bonding tool and the environment. This cooling member has a cooling function that actively removes heat from the bonding tool, enabling rapid temperature reduction without relying on slow air cooling. The cooling member acts as a heat exchange mediator that facilitates efficient thermal energy removal from the bonding tool.
Solution Approach 2:
The invention changes the thermal parameters of the bonding tool by introducing an active cooling mechanism. Instead of relying on passive air cooling that maintains ambient temperature, the cooling member enables active temperature control, rapidly changing the bonding tool temperature from above the non-conductive film melting point to below it, thereby reducing the time the tool remains at harmful high temperatures.
2Ease of operation
If the chip is suctioned to the bonding tool with a gap from the holding member, then the chip can be transferred, but the position and direction of the chip are largely displaced
Solution Approach 1:
A support member is introduced as an intermediary structure that receives the chip from the holding member and transfers it to the bonding tool. This support member provides a stable intermediate platform that maintains chip position and orientation during the transfer process, preventing the large displacements that occur when chips are suctioned with gaps between components.
3Productivity
If the non-conductive film melts at the same time as the bumps, then the resin molding is performed during bonding, but the non-conductive film adversely attaches to the holding member when the bonding tool at high temperature contacts the chip
Solution Approach 1:
The cooling member acts as a thermal mediator that prevents harmful heat transfer to the holding member. By actively cooling the bonding tool, the cooling member ensures that even when the bonding tool contacts the chip during transfer, the temperature remains below the non-conductive film melting point, preventing the film from adhering to the holding member while still allowing efficient bonding operations.
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 reduces bonding time by enabling higher temperatures for the bonding tool during chip transfer, thereby enhancing alignment and quality while shortening the overall bonding cycle.
Implementation Method 1
a cooling mechanism configured to cool the holding member to a predetermined temperature before the bonding tool receives the chip, allowing for efficient heat transfer
Implementation Method 2
the temperature of the bonding tool is increased up to the melting temperature of bumps (about 300°C.), the non-conductive film (NCF) melts at the same time as the bumps melt
Implementation Method 3
the temperature of the bumps and the non-conductive film (NCF) decreases and the metal of the molten bumps and the molten resin are hardened
Data Source
AI summary
Provided is a flip chip bonder including: a pickup flipping collet configured to flip a chip; and a bonding tool configured to receive the chip flipped with the pickup flipping collet from the pickup flipping collet and to bond the received chip to a circuit board. The pickup flipping collet includes a cooling channel through which cooling air flows to cool the pickup flipping collet. Thus, bonding time can be reduced without lowering bonding quality.