Bond Head Optical Positioning Across Different Focal Planes
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Solution Overview
Problem
Existing optical systems in bonding machines are limited by their depth of field, leading to inaccuracies in aligning semiconductor devices due to differences in height or level between the bond head and the substrate, which affects the precision of pick-and-place operations.
Innovation Solution
A method and apparatus that utilize two optical systems with adjustable focal planes to determine the position and orientation of both the bond head and the substrate independently, allowing for adjustments to correct relative offsets and improve alignment accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single optical system is used to view both the bond head and substrate, then the system structure is simple, but the alignment accuracy deteriorates due to depth of field limitations when objects are at different heights
Solution Approach 1:
The optical system is segmented into two independent optical systems: a first optical system for viewing the bond head at a first focal plane, and a second optical system for viewing the substrate at a second focal plane. This segmentation allows each optical system to be optimized for its specific viewing target, eliminating the depth of field limitations that would affect a single optical system attempting to view both objects at different heights simultaneously.
Data Source
Figure 1
Figure 2~3A
Figure 3B~3C
AI summary
After a die is picked up with a bond head, a first optical system views and determines a position and orientation of the die relative to the bond head. Separately, a second optical system views and determines a position and orientation of the bonding location when the second optical system has its focal plane configured at a first distance from the second optical system. After the bond head is moved adjacent to the second optical system, the second optical system views and determines a position and orientation of the bond head when the second optical system has its focal plane configured at a second distance from the second optical system. The position and orientation of the die may then be adjusted to correct a relative offset between the die and the bonding location prior to depositing the die onto the bonding location.