Semiconductor Package Dams for Sensor Region Contamination Control
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Solution Overview
Problem
The reliability of semiconductor packages, particularly those with image sensor chips, is compromised due to adhesive bleeding onto active or non-active areas during packaging, leading to optical failures and reduced package performance.
Innovation Solution
A semiconductor package design featuring a dam structure, such as a die dam or cover dam, is implemented to prevent contaminants like adhesive and encapsulant from bleeding beyond the dam, ensuring the sensor region remains protected and free from contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive is used to attach the cover to the die, then the cover is securely attached, but the adhesive bleeds to the active or sensor area causing optical failure
Solution Approach 1:
A dam structure (adhesive barrier) is introduced as an intermediary element between the adhesive and the sensor region. This barrier prevents direct contact between the adhesive and the sensor area, allowing the adhesive to perform its attachment function without causing optical failure. The dam structure acts as a physical mediator that controls adhesive flow while maintaining secure cover attachment.
2Strength
If adhesive is used to attach the cover, then the cover is secured, but contaminants bleed over the exposed top surface during encapsulation
Solution Approach 1:
The dam structure serves as a protective intermediary that shields the cover's top surface from encapsulant contamination. By positioning the adhesive barrier around the periphery, it creates a protected zone that prevents harmful encapsulant material from reaching and contaminating the exposed cover surface during the encapsulation process.
3Ease of manufacture
If no dam structure is used, then the manufacturing process is simpler, but adhesive and encapsulant bleed onto undesired areas
Solution Approach 1:
The dam structure is formed in advance on the cover surface before the encapsulation process. This preliminary preparation creates a pre-established barrier that automatically prevents adhesive and encapsulant bleeding during subsequent manufacturing steps. The advance formation of this protective structure simplifies the overall manufacturing process by eliminating the need for complex real-time control mechanisms.
4Reliability
If the dam structure is added, then contaminant bleeding is prevented, but the device complexity increases
Solution Approach 1:
The dam structure is implemented as a thin adhesive barrier layer deposited on the cover surface. This thin-film approach provides effective contaminant containment while minimizing the increase in device complexity. The adhesive barrier maintains flexibility and compatibility with existing package structures, avoiding the need for rigid or complex additional components.
Data Source
AI summary
A semiconductor package and a method of manufacturing thereof is disclosed. The package includes a package substrate having a die attach region with a die attached thereto. A protective cover is disposed over a sensor region of the die and attached to the die by a cover adhesive. The package includes a dam structure configured to protect components of the semiconductor package from contamination.