Interdigitated Clip Layout for Stress-Resistant Semiconductor Packages

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Solution Overview

Problem

Semiconductor device packages are prone to deformation and failure due to thermal or thermomechanical stress, which can cause the semiconductor die to break or the circuit to fail, especially when there are gaps between clips that create critical stress-sensitive areas.

Innovation Solution

The semiconductor device package design features interdigitated first and second clips with protrusions, redistributing stress across the semiconductor die by ensuring that at least one first protrusion extends between pairs of second protrusions, thereby reducing the risk of breakage during thermal cycling and operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If clips are arranged with gaps between them to connect to terminals, then electrical connection is achieved, but stress concentration occurs creating critical stress-sensitive areas on the semiconductor die

Engineering Contradiction:
Improvestress distributionVSAvoidstress concentration
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The clip structure is segmented into multiple protrusions (first protrusions on first clip, second protrusions on second clip) that are distributed across the semiconductor die surface. This segmentation allows stress to be distributed across multiple discrete contact points rather than concentrated in a single area, resolving the contradiction between achieving electrical connection and avoiding stress concentration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The protrusions are strategically positioned at specific locations on the semiconductor die, creating localized connection points with enhanced mechanical and electrical properties. Each protrusion provides a localized region of improved stress distribution and electrical contact, addressing the need for reliable connections while minimizing overall stress on the die.

Inventive Principle:
Principle #3Local quality

2Reliability

If clips are made larger to cover more area for better stress distribution, then stress redistribution is improved, but the package size increases

Engineering Contradiction:
Improvethermal cycling reliabilityVSAvoidpackage area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

Instead of using a single large clip, the invention uses multiple smaller protrusions distributed across the die surface. This segmentation achieves comprehensive stress distribution and thermal cycling reliability while maintaining a compact package footprint, as each protrusion is small but their collective coverage is extensive.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The clip structure transitions from a planar two-dimensional connection to a three-dimensional arrangement with protrusions extending in multiple directions. This dimensional change allows the clips to cover a larger effective area for stress distribution while maintaining a compact overall package size, as the protrusions utilize vertical and lateral space efficiently.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 effectively redistributes stress, improving the reliability and manufacturability of the package by reducing the risk of semiconductor die failure and enhancing thermal cycling reliability.

Implementation Method 1

a mismatch in coefficient of thermal expansion between the first and second clip and the semiconductor die. The above-described arrangement can redistribute stress across the semiconductor die and can reduce a risk of the semiconductor die breaking due to this stress

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

The semiconductor die, or the package as a whole, may be exposed to thermal or thermomechanical stress, for example during operation. Due to the stress, the package may for example be subjected to deformation.

Methodology Applied
Scientific EffectThermomechanical stress: Thermomechanical Effect

Data Source

PatentEP4261880A1Semiconductor device package and method for manufacturing the same
Publication Date: 2023.10.18 NEXPERIA BV
  • EP4261880A1 patent drawingFigure 1A~1B
  • EP4261880A1 patent drawingFigure 2
  • EP4261880A1 patent drawingFigure 3

AI summary

Aspects of the present disclosure relate to a semiconductor device package and to a method for manufacturing the same. The semiconductor device package comprises a semiconductor die having a circuit integrated thereon, a first clip comprising a first planar portion and one or more first leads extending from said first planar portion, the first planar portion comprising one or more first protrusions, and a second clip comprising a second planar portion and one or more second leads extending from said second planar portion, the second planar portion comprising a plurality of second protrusions. The first planar portion and the second planar portion each physically and electrically connected to a terminal of the circuit arranged on the semiconductor die. At least one of the one or more first protrusions extends in a space between a pair of second protrusions among the plurality of second protrusions.