Image Sensor Package Pillar Structure for Precise Air Gap Height
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Solution Overview
Problem
Conventional methods for controlling the gap height in image sensor packages are imprecise due to dependence on the volume and viscosity of bonding materials, leading to variations in the air gap height between the image sensor die and the glass substrate.
Innovation Solution
The method involves forming pillar members on the image sensor die, dispensing bonding material to cover these pillars, and then placing a transparent member on the bonding material, where the pillar height defines the gap height, ensuring a precise and consistent air gap by using the rigid structure of the pillars to maintain the transparent member's position during curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If bonding material is dispensed and glass substrate is dropped on it to define gap height, then the process is simple and fast, but the gap height varies due to dependence on resin volume and viscosity
Solution Approach 1:
The patent introduces pillar members as intermediary structures between the image sensor die and the transparent member. These pillars have a defined height that directly determines the gap height, serving as a mechanical mediator that eliminates the need to rely on bonding material volume and viscosity for gap definition. The bonding material becomes solely the bonding agent rather than the gap-defining element.
Solution Approach 2:
The pillar members are formed on the image sensor die before the bonding material is applied and before the transparent member is attached. This preliminary formation of structural elements that define the gap height allows the gap to be precisely controlled independent of subsequent bonding material properties, enabling consistent manufacturing.
2Ease of manufacture
If bonding material volume and viscosity are controlled to define gap height, then the process uses simple materials and methods, but variations in gap height occur during production
Solution Approach 1:
The pillar members serve as a reliable intermediary structure that mechanically defines the gap height. Instead of relying on the variable properties of bonding material (volume and viscosity), the pillar height provides a stable, controllable, and repeatable reference that ensures consistent gap formation throughout production.
Solution Approach 2:
The patent replaces the chemical/viscous-based gap definition method (relying on bonding material properties) with a mechanical-based method (using rigid pillar structures). This substitution provides more reliable and precise control over gap height, as mechanical dimensions can be controlled more accurately than fluid properties during manufacturing.
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 viscosity, resulting in consistent and reliable image sensor packages with defined air gaps, enhancing manufacturing accuracy and performance.
Implementation Method 1
The liquid epoxy resin is cured using ultraviolet (UV) light
Data Source
AI summary
According to an aspect, an image sensor package includes a substrate, an image sensor die coupled to the substrate, a light transmitting member, and a plurality of pillar members disposed between and contacting the image sensor die and the light transmitting member. A height of the plurality of pillar members defines a gap height between an active region of the image sensor die and the light transmitting member. The image sensor package including a bonding material that couples the light transmitting member to the image sensor. The bonding material contacts a side of a pillar member, of the plurality of pillar members, that extends between a first end contacting the light transmitting member and a second end contacting the image sensor die.