Wafer Reinforcing Ring Separation Using Groove-Initiated Division
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Solution Overview
Problem
The removal of the annular reinforcing part from the peripheral part of a thinned wafer is complicated and time-consuming, potentially damaging the device region due to its lowered rigidity, leading to increased operational costs and reduced efficiency.
Innovation Solution
A processing method involving a tape sticking step, holding step, cutting step, dividing step, and reinforcing part removal step, utilizing an adhesive tape and chuck tables with recesses and projections to facilitate easy separation and removal of the reinforcing part through cutting and fluid jetting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the peripheral part of the wafer is annularly cut by a cutting blade to separate the device region and a reinforcing part, then the reinforcing part can be removed, but the structure of the removal mechanism becomes complicated and the cost increases
Solution Approach 1:
The patent extracts the reinforcing part from the wafer by forming grooves that separate it from the device region, allowing the reinforcing part to be removed independently. This extraction approach simplifies the removal mechanism by eliminating the need for complex claw assemblies or multiple cutting blades, as the reinforcing part can be detached through the pre-formed grooves using simpler tools.
Solution Approach 2:
The patent segments the reinforcing part from the wafer by forming grooves that divide it into removable sections. This segmentation allows the reinforcing part to be separated into manageable pieces that can be easily removed without requiring complex mechanical structures, thereby reducing device complexity while maintaining ease of removal.
2Reliability
If the reinforcing part is carefully held and raised to avoid swing or position deviation, then the device region is protected from damage, but the work time becomes longer and operation efficiency lowers
Solution Approach 1:
The patent applies preliminary action by forming grooves in the reinforcing part before removal. These pre-formed grooves guide the separation process and prevent uncontrolled swinging or position deviation during removal. By preparing the grooves in advance, the actual removal operation becomes faster and more efficient, as the reinforcing part naturally follows the groove paths during detachment, eliminating the need for slow, careful manual positioning.
Solution Approach 2:
The grooves act as an intermediary structure that mediates between the reinforcing part and the removal process. These grooves provide a controlled path for separation, ensuring that the reinforcing part moves along predetermined trajectories rather than swinging freely. This intermediary structure protects the device region while enabling faster, more efficient removal operations.
3Strength
If only the region overlapping with the device region on the back surface side is ground and thinned, then the rigidity of the wafer is maintained, but a recess part is formed at the central part of the back surface side
Solution Approach 1:
The patent applies local quality by selectively thinning only the central region of the wafer back surface that overlaps with the device region, while leaving the peripheral reinforcing part at its original thickness. This creates a localized recess in the central area, giving different thickness characteristics to different regions: the central device region becomes thinner for device fabrication requirements, while the peripheral reinforcing part remains thick to maintain overall wafer rigidity.
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
Enables efficient and simple removal of the reinforcing part by dividing it into chips, reducing operational complexity and time, while minimizing the risk of damage to the device region.
Implementation Method 1
a tape sticking step of sticking an adhesive tape to the back surface side of the wafer along the recess part and the reinforcing part
Implementation Method 2
a dividing step of dividing the reinforcing part along the planned dividing lines with the grooves being points of origin by giving an external force to the reinforcing part
Data Source
AI summary
There is provided a processing method of a wafer for processing the wafer that includes, on a front surface side, a device region in which a device is formed in each of plural regions marked out by plural planned dividing lines and includes a recess part on the back surface side and includes an annular reinforcing part at a peripheral part. The processing method of a wafer includes a holding step of holding the bottom surface of the recess part, a cutting step of cutting the wafer along the planned dividing lines by a cutting blade to divide the device region into plural device chips and form grooves on the front surface side of the reinforcing part, and a dividing step of dividing the reinforcing part along the planned dividing lines with the grooves being the points of origin by giving an external force to the reinforcing part.