Image Sensor Package Assembly with Pillar-Defined Gap Height
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Solution Overview
Problem
Conventional methods for controlling the gap height in image sensor packages are inaccurate due to dependence on the volume and viscosity of bonding materials, leading to variations in production.
Innovation Solution
The method involves forming pillar members on the image sensor die, dispensing bonding material to cover these pillars, and using a transparent member with a bond head to define the gap height, ensuring precision by controlling the position and curing of the bonding material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If bonding material volume and viscosity are used to control gap height, then the process is simple, but manufacturing precision deteriorates due to variations in gap height
Solution Approach 1:
The patent introduces pillar members as intermediary structures between the image sensor die and the transparent member. These pillars have a predetermined height that directly defines the gap height, serving as a mechanical mediator that eliminates the need to rely on bonding material volume and viscosity for gap control. The bonding material simply fills the space around the pillars rather than determining the gap dimension.
Solution Approach 2:
The pillar members are formed on the image sensor die before the bonding material is applied. This preliminary formation of height-defining structures allows the gap height to be predetermined and controlled independently of subsequent bonding material properties. The pillars are pre-configured to the exact desired gap dimension before assembly proceeds.
2Device complexity
If bonding material properties are used to define gap height, then fewer process steps are needed, but reliability worsens due to production variations
Solution Approach 1:
The pillar members act as reliable intermediary structures that mechanically define the gap height with high consistency. By transferring the gap definition function from the bonding material (which has variable properties) to the rigid pillar structures (which have predetermined, stable dimensions), the system achieves higher reliability and consistency in gap height across production batches.
Solution Approach 2:
The patent changes the critical parameter for gap height definition from bonding material properties (volume, viscosity) to pillar member geometry (height, position). This parameter change shifts the control mechanism from material-dependent variables to geometrically-defined constants, thereby improving reliability and reducing production variations.
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 allows for precise control of the gap height, independent of bonding material properties, resulting in consistent and reliable image sensor package fabrication.
Implementation Method 1
The liquid epoxy resin is cured using ultraviolet (UV) light
Data Source
AI summary
According to an aspect, a method for fabricating an image sensor package to define a gap height includes coupling an image sensor die to a substrate, forming a plurality of pillar members on the image sensor die, dispensing a bonding material on the image sensor die, contacting a transparent member with the bonding material such that a height of the pillar members defines a gap height between an active region of the image sensor die and the transparent member, and curing the bonding material to couple the transparent member to the image sensor die.