Cap Wafer Grooves for MEMS Dicing Swarf Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In micromachine device manufacturing, cutting water containing swarf often enters the moving portions of MEMS devices during the dicing process, damaging the devices and leaving adhesive residue after peeling off protective films, which deteriorates the quality of the micromachine devices.
Innovation Solution
A method involving a cap wafer with dividing grooves is used to protect the functional wafer, where the cap wafer is joined and ground to expose the grooves, allowing for cutting without swarf entering the devices and eliminating the need for peeling off the cap wafer, thus preventing adhesive residue and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cutting water is supplied to the portion to be cut, then cutting efficiency is improved, but cutting water containing swarf enters the moving portion of the micromachine device, deteriorating the quality of the micromachine device
Solution Approach 1:
A protective film is introduced as an intermediary layer between the micromachine device and the cutting environment. This film prevents cutting water and swarf from directly contacting and contaminating the moving portions of the micromachine device, while still allowing the cutting process to proceed efficiently with water cooling.
2Object-affected harmful factors
If an ultraviolet-sensitive adhesive film is stuck to the face of the semiconductor wafer for protection, then the moving portion is protected from swarf, but adhesive paste remains on the surface after peeling, deteriorating the quality of the micromachine device
Solution Approach 1:
The protective film is designed as a disposable, single-use element that is removed after the cutting process. Unlike adhesive films that leave residue, this protective film can be cleanly peeled off without leaving adhesive paste on the micromachine device surface, maintaining surface quality.
3Object-affected harmful factors
If an ultraviolet-sensitive adhesive film is used for protection, then the moving portion is protected from swarf, but the micromachine device is damaged when the film is peeled off
Solution Approach 1:
The protective film is designed as a temporary, disposable barrier that provides protection during cutting and can be cleanly removed without causing damage. The film's design allows for clean separation from the micromachine device surface, preventing the damage that occurs when adhesive films are peeled off.
4Object-affected harmful factors
If the cap wafer is joined to the face of the functional wafer, then the moving portion is protected from cutting water, but the cap wafer needs to be removed to expose the electrodes
Solution Approach 1:
The cap wafer is segmented with through-holes that expose the electrodes while the surrounding cap structure remains intact to provide protection. This segmentation allows the cap wafer to simultaneously fulfill both protective and access functions, eliminating the need to remove the entire cap wafer to expose the electrodes.
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
This method effectively prevents swarf from entering the micromachine devices during cutting and eliminates the need for peeling off protective films, maintaining the quality of the micromachine devices by using the cap wafer as a protective cap after division.
Implementation Method 1
a cap wafer grinding step of grinding other surface of the cap wafer joined to the face of the functional wafer to expose the dividing grooves to an outside
Implementation Method 2
A functional wafer grinding step of grinding the back of the functional wafer, to which the cap wafer has been joined, to the finished thickness of the functional wafer
Data Source
AI summary
A micromachine device processing method for dividing a functional wafer, which has micromachine devices formed in a plurality of regions demarcated by streets formed in a lattice pattern on a face of the functional wafer, along the streets into the individual micromachine devices, each micromachine device having a moving portion and an electrode, comprising: a cap wafer groove forming step of forming dividing grooves, which have a depth corresponding to a finished thickness of a cap wafer for protecting the face of the functional wafer, along regions in one surface of the cap wafer which correspond to areas of the electrodes of the micromachine devices; a cap wafer joining step of joining the one surface of the cap wafer subjected to the cap wafer groove forming step to the face of the functional wafer at peripheries of the moving portions; a cap wafer grinding step of grinding the other surface of the cap wafer joined to the face of the functional wafer to expose the dividing grooves to the outside; and a cutting step of cutting the functional wafer and the cap wafer subjected to the cap wafer grinding step along the streets.