Semiconductor Package Dam Structure for NCF Overflow Control
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Solution Overview
Problem
The challenge in semiconductor packaging is to achieve miniaturization, lightness, high performance, and large capacity while preventing non-conductive film (NCF) overflow, which can lead to non-filling and voids between stacked semiconductor chips, affecting manufacturing quality and reliability.
Innovation Solution
A semiconductor package design that includes a dam structure on the base substrate to surround the semiconductor chips, with the dam structure's thickness matching the chip and NCF thickness, limiting NCF overflow and enhancing filling rates, and using a molding member to cover the chips and NCF, ensuring uniform bonding and structural reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If semiconductor chips are stacked to achieve miniaturization and large capacity, then the package size is reduced and capacity is increased, but non-conductive film overflow occurs causing voids and bonding defects
Solution Approach 1:
The dam structure is formed on the base substrate before the stacking process begins. This preliminary structure prevents NCF overflow in advance by creating containment walls at the periphery, ensuring that subsequent bonding operations do not produce voids or defects from material overflow.
Solution Approach 2:
The dam structure acts as an intermediary element between the NCF and the external environment. It mediates the bonding process by containing the NCF within a defined region, preventing it from overflowing while still allowing the chips to be stacked and bonded effectively.
2Reliability
If the dam structure thickness is increased to prevent NCF overflow, then overflow prevention is improved, but the complexity of maintaining uniform thickness with chip and NCF increases
Solution Approach 1:
The patent specifies that the dam structure thickness is set to substantially match the combined thickness of the chip and NCF. This parameter matching creates a uniform upper surface that simplifies the overall structure and eliminates the need for additional complex components to achieve flatness.
Solution Approach 2:
By making the dam structure thickness equal to the chip and NCF thickness, the patent creates an equipotential upper surface where all components align at the same level. This eliminates height differences that would otherwise require additional processing steps or components.
3Manufacturing precision
If NCF is applied generously to ensure complete coverage, then bonding coverage is improved, but overflow occurs causing voids and filling defects
Solution Approach 1:
The patent converts the potential harm of NCF overflow into a benefit by using the dam structure to define precise application boundaries. The NCF is applied generously within the contained region, and the dam walls prevent harmful overflow while ensuring complete coverage within the intended area.
Solution Approach 2:
The dam structure creates a localized region with different properties from the surrounding area. Within the dam-contained region, NCF is allowed to flow freely for complete coverage, while outside this region, the dam walls prevent overflow. This local differentiation solves both coverage and overflow problems.
Data Source
AI summary
A semiconductor package includes a base substrate, a first semiconductor chip on the base substrate, a dam structure on the base substrate and surrounding the first semiconductor chip, a second semiconductor chip on the first semiconductor chip, a non-conductive film, and a molding member. The non-conductive film may be between the base substrate, the first semiconductor chip, and the second semiconductor chip. The molding member may cover the base substrate, the first semiconductor chip, and the second semiconductor chip. A level of an upper surface of the first semiconductor chip and a level of an upper surface of the dam structure may be at a same level.