Leadframe Conductive Pillar Void Elimination via Etching
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Solution Overview
Problem
The existing leadframe manufacturing methods often result in conductive pillars with voids and varying heights due to the plating process, which adversely affect the electrical performance of semiconductor device packages.
Innovation Solution
A leadframe design featuring a patterned conductive layer with integrated conductive pillars of uniform height, covered by a package body, and electrical connections exposed for improved electrical performance, along with a manufacturing method that includes forming conductive pillars on a metal plate using etching and patterning to ensure void-free and uniform pillar heights.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conductive pillars are formed by plating on a metal plate, then the leadframe can be manufactured, but voids are formed within the conductive pillars and pillar heights vary
Solution Approach 1:
The patent applies preliminary action by forming a protective layer on the metal plate before forming the conductive pillars. This protective layer prevents material loss during etching and ensures uniform pillar heights by providing a consistent starting surface for the plating process, thereby resolving the height uniformity issue while maintaining manufacturing feasibility
2Ease of manufacture
If conductive pillars are formed by plating, then the leadframe structure can be created, but voids are formed within the pillars affecting electrical performance
Solution Approach 1:
The protective layer is applied in advance before pillar formation to ensure complete and uniform material deposition. This preliminary action prevents void formation by maintaining consistent plating conditions across all pillars, thereby improving electrical performance while keeping the manufacturing process simple
Solution Approach 2:
The protective layer acts as an intermediary between the metal plate and the conductive pillar formation process. It mediates the plating process by providing a uniform surface that ensures consistent material deposition, eliminating voids and improving electrical reliability without complicating the overall manufacturing approach
3Reliability
If the leadframe is made thin for high reliability, then reliability improves, but support capability decreases
Solution Approach 1:
The patent creates a composite structure by forming conductive pillars on the thin metal plate and covering them with a protective layer. This composite design allows the leadframe to maintain thinness for reliability while the pillars and protective layer provide the necessary support capability, resolving the contradiction between reliability and strength
Data Source
AI summary
A leadframe includes a first conductive layer, a plurality of conductive pillars and a first package body. The first conductive layer has a first surface and a second surface opposite to the first surface. The plurality of conductive pillars are disposed on the first surface of the first conductive layer. The first package body is disposed on the first surface of the first conductive layer and covers the conductive pillars. The conductive pillars and the first conductive layer are integratedly formed.