Grinding Wheel Bonding via Ultrasonic Surface Texturing
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Solution Overview
Problem
The existing grinding wheels for wafer thinning in device chip manufacturing face issues with grindstones coming off the annular base due to insufficient bonding strength, leading to instability during the grinding process.
Innovation Solution
The method involves applying ultrasonic vibrations through water to create surface unevenness on the annular slot of the grinding wheel's base, increasing the contact area between the base and the adhesive, thereby enhancing the bonding strength of the grindstones to the base.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If grindstones are fixed to the annular base with adhesive in a narrow annular slot, then the grinding wheel can be manufactured with compact structure, but the bonding strength is insufficient and grindstones may come off during grinding
Solution Approach 1:
The invention applies local quality by creating surface unevenness specifically at the bottom of the annular slot where the adhesive contacts the base. This localized surface modification increases the adhesive bonding area and strength precisely where needed, without changing the overall compact structure of the grinding wheel.
Solution Approach 2:
The surface unevenness is formed on the annular base before the grindstones are fixed with adhesive. This preliminary action prepares the bonding surface in advance, ensuring that when the adhesive is applied, it immediately contacts the uneven surface for enhanced bonding strength from the start.
2Device complexity
If the annular slot width is kept small to maintain compact design, then the grinding wheel structure remains compact, but the adhesive bonding area is reduced leading to insufficient bonding strength
Solution Approach 1:
The invention transitions from a two-dimensional flat bonding surface to a three-dimensional uneven surface by creating protrusions and recesses at the bottom of the annular slot. This dimensional change increases the effective bonding area without increasing the overall width of the annular slot, thus maintaining structural compactness while enhancing bonding area.
3Strength
If ultrasonic vibrations are applied to form surface unevenness, then the bonding strength increases, but the manufacturing process becomes more complex
Solution Approach 1:
The invention uses ultrasonic vibrations to form surface unevenness on the annular base. The ultrasonic vibration applying unit generates high-frequency vibrations that, when applied through water, create the desired surface protrusions and recesses at the bottom of the annular slot, enhancing adhesive bonding strength.
Solution Approach 2:
Water serves as an intermediary medium to transmit ultrasonic vibrations from the ultrasonic vibration applying unit to the annular base. The water facilitates the transmission of mechanical energy while protecting the base material from direct contact with the vibration source, enabling controlled surface modification.
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 increased bonding strength prevents grindstones from detaching during grinding, ensuring a stable and effective process for wafer thinning, as demonstrated by experimental tests showing higher maximum stresses and improved bonding performance with extended ultrasonic vibration application times.
Implementation Method 1
a surface unevenness forming step of applying ultrasonic vibrations from an ultrasonic vibration applying unit (14) through water (10) to an annular slot (4d) defined in a surface (4a) of an annular base (4) along circumferential directions (4A) thereof, thereby forming surface unevennesses (4e1 to 4e3) on either one or both of side surfaces (4d1) and a bottom surface (4d2) of the annular slot (4d)
Data Source
AI summary
A method of manufacturing a grinding wheel includes a surface unevenness forming step of applying ultrasonic vibrations from an ultrasonic vibration applying unit through water to an annular slot defined in a surface of an annular base along circumferential directions thereof, thereby forming surface unevennesses on either one or both of a side surface and a bottom surface of the annular slot, and, after the surface unevenness forming step, a grindstone fixing step of fixing a plurality of grindstones to the annular slot with an adhesive.