Optical Component Bonding on Sensor Chips Using Spacer Fixation
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Solution Overview
Problem
The existing manufacturing methods for semiconductor sensor modules face challenges in achieving precise positioning of optical components over sensor chips, leading to positional shifts and reduced transmittance due to the use of adhesives with flowability and uneven curing, especially when heat is applied to cure the adhesive under load.
Innovation Solution
A method involving the formation of spacers on the sensor chip and optical component surfaces using cured adhesive, allowing precise alignment and temporary fixation of optical components during adhesive curing without applied load, ensuring high precision and uniform adhesive thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If adhesive in paste state is used to fix optical component on sensor chip, then the optical component can be bonded and fixed, but the optical component moves before the adhesive is cured causing positional shift
Solution Approach 1:
The patent applies preliminary action by using a first adhesive to form spacers that temporarily fix the optical component in the correct position before the second adhesive is applied and cured. This preliminary fixation prevents positional shifts during the bonding process while allowing the final adhesive to cure without load application.
2Productivity
If heat is applied to cure the adhesive while the optical component is held by bonding tool, then the adhesive cures faster, but the transmittance of the cured adhesive is reduced due to non-uniform thickness
Solution Approach 1:
The spacers are formed in advance using the first adhesive before the second adhesive is applied. These pre-formed spacers define the bonding gap and ensure uniform adhesive thickness distribution when the optical component is bonded, preventing interference patterns while allowing efficient curing.
Solution Approach 2:
The bonding process is segmented into two stages: first forming spacers with one adhesive, then bonding with a second adhesive. This segmentation allows the spacers to pre-establish the correct geometry and thickness distribution, enabling the second adhesive to cure uniformly without bearing mechanical load.
3Measurement precision
If the optical component is disposed precisely with respect to the sensor chip, then initial alignment is good, but the component still moves before adhesive curing
Solution Approach 1:
The spacers are formed as a preliminary action before the final bonding step. These spacers act as temporary fixtures that maintain the precisely aligned position of the optical component during adhesive application and curing, preventing any movement that would occur with paste-state adhesive alone.
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 approach enables precise fixation of optical components over sensor chips, preventing positional shifts and maintaining high transmittance of the adhesive, thereby improving the overall performance and thickness reduction of semiconductor devices.
Implementation Method 1
a first adhesive is disposed on the front surface of the sensor chip at a plurality of positions, and a plurality of first spacers having adherence is formed on the front surface of the sensor chip by curing this first adhesive
Implementation Method 2
the first optical component is fixed by curing the second adhesive in a state that no load is applied to the first optical component
Data Source
AI summary
An optical component is fixed precisely on a sensor chip. After a sensor chip including a front surface having a sensor plane with a plurality of light receiving elements is mounted face-up over a wiring substrate, an adhesive is disposed on the front surface of the sensor chip at a plurality of positions, and a plurality of spacers having adherence is formed by curing this adhesive. Then, an adhesive paste is disposed on the front surface of the sensor chip. Then, an optical component held by a bonding tool is disposed on the front surface via the spacer and the adhesive. After that, the bonding tool is separated from the optical component and the optical component is fixed by curing the adhesive in a state in which a load is not applied to the optical component.