Wafer Dicing Carrier Connection for Reduced Bending Stress
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Solution Overview
Problem
The existing methods for dividing wafers into dies using adhesive tape and carriers result in die shifting, high unit costs, and increased rejection rates due to bending stresses during detachment, which complicates the fabrication process and reduces productivity.
Innovation Solution
Attaching an adhesive tape to the wafer with a carrier that is connected via removable connecting means located outside the device area, allowing for reduced bending stresses and easier detachment without damaging the wafer or carrier, thereby minimizing die shifting and rejection rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the carrier is glued to the adhesive tape over its whole surface area, then die shifting is eliminated, but large bending stresses are generated during detachment causing damage to wafer and carrier
Solution Approach 1:
The connection area between carrier and adhesive tape is segmented into two distinct zones: a large glued area in the peripheral marginal region for mechanical support, and a smaller connecting means area that allows controlled detachment. This segmentation enables the carrier to remain rigid during processing while permitting stress-free separation without damaging the wafer or carrier.
Solution Approach 2:
Different regions of the carrier-adhesive tape interface have different connection characteristics. The peripheral marginal area has strong glued connection for stability, while the device area has controlled connecting means for detachment. This local differentiation allows the system to simultaneously achieve both strong attachment and easy release without compromising structural integrity.
2Reliability
If the wafer is detached from the carrier slowly and carefully, then damage to wafer and carrier is reduced, but productivity is reduced due to reduced throughput
Solution Approach 1:
The connecting means is pre-configured in the adhesive tape at locations that allow controlled detachment. This preliminary preparation enables the carrier to be removed quickly and easily after processing, eliminating the need for slow and careful manual detachment while maintaining wafer and carrier integrity.
Solution Approach 2:
The connection between carrier and adhesive tape transitions from a static strong bond (during processing) to a dynamic controllable release (during detachment). The connecting means enables this dynamic transition, allowing the system to maintain strong attachment during grinding and cutting, then easily separate afterward to maximize productivity.
3Reliability
If the adhesive tape adheres to devices on the wafer, then devices are protected during processing, but devices may be damaged during carrier detachment due to bending stresses
Solution Approach 1:
The adhesive tape connection to the carrier is segmented into two functional zones: the peripheral marginal area provides strong mechanical support through gluing, while the device area uses controlled connecting means that minimize stress transmission to the devices during detachment, protecting them from damage.
Solution Approach 2:
The connecting means acts as an intermediary between the carrier and the adhesive tape in the device area. It provides a controlled detachment interface that reduces bending stresses transmitted to the devices, allowing the adhesive tape to remain attached to devices for protection while enabling stress-free separation during carrier removal.
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 method reduces unit costs and improves productivity by minimizing die shifting and rejection rates, allowing for efficient and precise processing of wafers into dies without damaging the devices or carrier.
Implementation Method 1
an adhesive tape for protecting devices on the wafer is attached to the one side of the wafer, the adhesive tape adhering to at least some, optionally all, of the devices
Implementation Method 2
a carrier, being made of a material harder and more rigid than that of the adhesive tape, for supporting the adhesive tape is connected to the side of the adhesive tape being opposite to the side in contact with the devices, by connecting means
Implementation Method 3
grinding the side of the wafer being opposite to the one side for adjusting the wafer height
Data Source
AI summary
A method of dividing a wafer, having on one side a device area with a plurality of devices partitioned by a plurality of division lines and a peripheral marginal area with no devices formed around the device area, into dies is provided. The method comprises: attaching an adhesive tape for protecting devices on the wafer to the one side of the wafer, the adhesive tape adhering to at least some, optionally all, of the devices; connecting a carrier for supporting the adhesive tape to the side of the adhesive tape being opposite to the side in contact with the devices by connecting means; grinding that side of the wafer being opposite the one side for adjusting the wafer height; and cutting the wafer along the division lines. The method is characterized by locating the connecting means completely outward of the device area of the wafer in a top view thereon.