Prefabricated Multi-Die Leadframe for Stacked Semiconductor Interconnect
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Solution Overview
Problem
Conventional semiconductor device manufacturing processes require expensive deep via formation and fine top die placement, increasing costs and complexity in electrical interconnection of stacked semiconductor die.
Innovation Solution
A method involving a substrate with contact pads or conductive fingers to electrically interconnect stacked semiconductor die without forming deep vias, using a prefabricated multi-die leadframe for structural support and interconnection, which simplifies the manufacturing process and reduces costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional deep via formation and fine top die placement are used for electrical interconnection of stacked semiconductor die, then reliable electrical connection is achieved, but manufacturing cost and process complexity increase
Solution Approach 1:
The patent introduces an intermediate substrate with pre-formed contact pads that acts as a mediator between the stacked semiconductor die. This substrate receives bump structures from multiple die and provides electrical interconnection without requiring deep via formation through the die themselves, thereby simplifying the manufacturing process while maintaining reliable electrical connections.
Solution Approach 2:
The substrate is prepared in advance with pre-formed contact pads and conductive structures before the semiconductor die are mounted. This preliminary preparation of the interconnection architecture eliminates the need for complex post-assembly via formation and routing operations, reducing overall manufacturing complexity.
2Reliability
If deep vias are formed through silicon or organic material to achieve electrical interconnection, then conductive pathways are established, but manufacturing cost and process difficulty increase
Solution Approach 1:
The substrate serves as an intermediary that provides pre-formed conductive pathways through its contact pads and conductive structures. This eliminates the need to form deep vias through the semiconductor die or encapsulant material, significantly simplifying the manufacturing process while ensuring reliable electrical connection between stacked die.
Solution Approach 2:
Instead of forming conductive pathways by drilling or etching deep vias through the die and encapsulant (upward from the bottom), the patent inverts the approach by providing pre-formed conductive structures on the substrate that receive electrical connections from the die bumps, thereby eliminating the need for difficult deep via formation.
Data Source
AI summary
A prefabricated multi-die leadframe having a plurality of contact pads is mounted over a temporary carrier. A first semiconductor die is mounted over the carrier between the contact pads of the leadframe. A second semiconductor die is mounted over the contact pads of the leadframe and over the first die. An encapsulant is deposited over the leadframe and first and second die. The carrier is removed. A first interconnect structure is formed over the leadframe and the first die and a first surface of the encapsulant. A channel is cut through the encapsulant and leadframe to separate the contact pads. A plurality of conductive vias can be formed through the encapsulant. A second interconnect structure is formed over a second surface of the encapsulant opposite the first surface of the encapsulant. The second interconnect structure is electrically connected to the conductive vias.