Segmented Bond Collet with Independent Pneumatic Suction for Flip Chip Bonding
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Solution Overview
Problem
Conventional flip chip bonder throughput is limited due to individual transfer and bonding of semiconductor devices, requiring precise alignment, slow Z-axis speed, low temperature for adhesive curing, and long heating and cooling times, which restricts the thermocompression bonding process efficiency.
Innovation Solution
A device with multiple support surfaces and internal conduits for independent pneumatic suction control, allowing simultaneous transfer and bonding of semiconductor devices, coupled with a heater for efficient thermocompression bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If individual transfer and bonding of semiconductor devices is performed, then precise alignment between flip chips and bond pad positions is achieved, but throughput capacity is limited to about 500 units per hour
Solution Approach 1:
The bond collet is divided into multiple support surfaces (at least two) that can independently hold multiple flip chips simultaneously. Each support surface has independent pneumatic control through separate conduits, allowing individual or collective holding and release of devices, enabling parallel processing while maintaining alignment precision
Solution Approach 2:
Multiple flip chips are held and transferred simultaneously on a single bond collet rather than individually. The imaging system captures positions of multiple devices at once, and thermocompression bonding is performed on multiple devices in parallel, combining multiple operations into one cycle to increase throughput while maintaining precision
2Reliability
If slow Z-axis speed is used to avoid air void formation in adhesives, then bonding quality is improved, but cycle duration increases reducing throughput
Solution Approach 1:
Thermocompression bonding is performed simultaneously on multiple flip chips during a single continuous Z-axis movement cycle, rather than sequentially. The bonding force and temperature are applied continuously to all devices at once, eliminating the need for repeated slow approach cycles and reducing overall cycle time while maintaining bonding quality
Solution Approach 2:
Multiple flip chips are pre-positioned on the bond collet and their positions are pre-measured by the imaging system before the bonding cycle begins. This allows the system to plan and execute a single coordinated bonding operation for all devices, reducing the number of cycles needed and increasing throughput
3Reliability
If low temperature is used for adhesive contact, then air void formation is avoided, but curing time increases extending cycle duration
Solution Approach 1:
The bonding process utilizes controlled phase transition through temperature profiling. The bond collet temperature is dynamically adjusted during the cycle: initially kept lower to prevent air void formation during contact, then raised to accelerate adhesive curing. This temperature phase transition allows both quality and speed requirements to be met within a single cycle
Solution Approach 2:
The thermocompression bonding process employs periodic temperature variation on the bond collet. The temperature profile includes an initial lower temperature phase for contact, followed by a heating phase for curing. This periodic temperature action enables sequential achievement of different bonding requirements within one cycle, reducing total cycle time
4Temperature
If long heating time is applied to heat up flip chips, then bonding temperature is achieved, but cycle duration increases reducing throughput
Solution Approach 1:
The bond collet and its internal conduits are pre-heated before flip chips are loaded. This preliminary heating reduces the thermal mass that needs to be heated during the bonding cycle, allowing faster temperature rise and reducing the heating portion of the cycle time while still achieving the required bonding temperature
5Ease of operation
If long cooling time is applied to cool the bond collet, then device pickup is enabled, but cycle duration increases reducing throughput
Solution Approach 1:
The bond collet is segmented into multiple zones with independent pneumatic control. This allows selective release of individual flip chips or groups of chips at different times during the cycle. Devices can be released progressively as they bond, or in batches, eliminating the need to wait for complete cooling of the entire collet and reducing idle time
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 increases the throughput capacity of flip chip bonders by 100% to 1000 units per hour, improving efficiency and reducing cycle duration through simultaneous handling and bonding of multiple devices.
Implementation Method 1
a plurality of internal conduits within the body, each internal conduit extending from an opening of a respective one of the support surfaces at the first side of the body to an opening at a second side of the body. In particular, the openings at the second side of the body are configured to be connected to separate pneumatic paths in fluid communication therewith each pneumatic path having an independently controlled pneumatic suction force
Implementation Method 2
The apparatus comprises: a heater and the above device coupled to the heater, wherein the heater is operative to heat the device to thereby heat the semiconductor devices that are being held
Data Source
AI summary
Disclosed is a device for holding a plurality of semiconductor devices during thermocompression bonding, comprising: a body; a plurality of support surfaces at a first side of the body, each support surface being configured for holding at least one semiconductor device during thermocompression bonding; and a plurality of internal conduits within the body, each internal conduit extending from an opening of a respective one of the support surfaces at the first side of the body to an opening at a second side of the body. In particular, the openings at the second side of the body are configured to be connected to separate pneumatic paths to be in fluid communication therewith, each pneumatic path having an independently controlled pneumatic suction force so that the openings of the support surfaces at the first side of the body are operative to selectively hold the one or more semiconductor devices against the support surfaces at the first side of the body or to release the same therefrom. An apparatus for holding semiconductor devices during thermocompression bonding, and a method of bonding a plurality of semiconductor devices to a substrate via thermocompression bonding are also disclosed.