Electroplated Leadframe with Overlapping Bond Pad for Thin Semiconductor Package

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Solution Overview

Problem

The demand for lighter, thinner, and more compact semiconductor packaging solutions is hindered by the weight and volume of traditional leadframes, which are not aligned with the trend towards smaller electronic products.

Innovation Solution

A semiconductor package design featuring a conductive carrier with a first metal layer comprising a lead pad and a second metal layer with a bond pad, where the bond pad overlaps and partially overlaps the lead pad, allowing for external electrical connections and encapsulation, reducing the overall thickness and weight through a thin electroplated leadframe structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If a traditional leadframe structure is used, then electrical connection and structural support are provided, but the package weight and volume increase

Engineering Contradiction:

Improvepackage weightVSAvoidelectrical connection reliability

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The patent extracts and removes the traditional heavy leadframe structure from the semiconductor package, retaining only the essential electrical connection functions through bond pads and lead pads that are directly formed on the substrate, thereby significantly reducing package weight and volume while maintaining electrical connectivity

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs thin metal layers (first metal layer and second metal layer) with thicknesses of 1-10 micrometers to replace the bulky leadframe, creating a lightweight yet conductive structure that provides necessary electrical pathways without adding excessive weight or volume

Inventive Principle:

Principle #30Flexible shells and thin films

2Length of moving object

If a traditional leadframe structure is used, then structural support is provided, but the package thickness increases

Engineering Contradiction:

Improvepackage thicknessVSAvoidstructural support strength

Core Design Contradiction:

Length of moving objectVSStrength

Solution Approach 1:

The patent removes the thick leadframe structure and replaces it with thin metal layers directly patterned on the substrate, reducing package thickness from millimeter scale to micrometer scale while the substrate itself provides the primary structural support

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates a composite structure combining the substrate (providing mechanical strength and support) with thin metal layers (providing electrical conductivity), where each material performs its optimal function without requiring excessive thickness

Inventive Principle:

Principle #40Composite materials

3Reliability

If bond pad overlaps lead pad structure is implemented, then adhesion and reliability are improved, but manufacturing complexity increases

Engineering Contradiction:

Improveadhesion reliabilityVSAvoidmanufacturing ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent performs preliminary patterning of the lead pad structure in the first metal layer before forming the bond pad structure in the second metal layer, allowing the bond pad to be precisely positioned to overlap the lead pad edge, thereby ensuring optimal adhesion and electrical connection before final assembly

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent divides the electrical connection structure into two separate metal layers with distinct functions: the first metal layer forms the lead pad for external connection, while the second metal layer forms the bond pad for die attachment, allowing independent optimization and manufacturing of each layer

Inventive Principle:

Principle #1Segmentation

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 design enables thinner semiconductor packages with improved adhesion and reliability, facilitating the integration of semiconductor dies while maintaining electrical connectivity, thus aligning with the goal of creating lighter and more compact electronic products.

Implementation Method 1

A first metal layer is formed on the conductive carrier... A second metal layer is formed on the first metal layer

Methodology Applied

Scientific EffectElectroplating: Electroplating

Data Source

PatentUS9305868B2Manufacturing method of forming an etch-back type semiconductor package with locking anchorages

Publication Date: 2016.04.05 ADVANPAK SOLUTIONS PTE

AI summary

A semiconductor package, a substrate and a manufacturing method thereof are provided. The substrate comprises a conductive carrier, a first metal layer and a second metal layer. The first metal layer is formed on the conductive carrier and comprises an lead pad having an upper surface. The second metal layer is formed on the first metal layer and comprises a bond pad. The bond pad overlaps and is in contact with the upper surface of the first metal layer. The upper surface of the lead pad is partially exposed. A part of the bond pad overhang outward from the edge of the lead pad.