Semiconductor Pad Slope Structure for Protective Film Crack Resistance

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Solution Overview

Problem

Conventional semiconductor devices experience cracks in the surface protective film covering the edges of pads due to stress from dicing and sealing, leading to reduced reliability.

Innovation Solution

Incorporating sloped portions on the connecting parts between pads and lead-out wiring portions, and ensuring the surface protective film completely fills the gaps between pads, to distribute stress and enhance crack resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the surface protective film covers the step caused by pad thickness, then the edge of the pad is protected, but cracks are generated on the surface protective film due to stress from dicing and sealing

Engineering Contradiction:

Improvecrack resistance of surface protective filmVSAvoidstress resistance of surface protective film

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The invention replaces the conventional vertical step structure with a sloped structure. The side surface of the pad is formed with a slope angle of 45 degrees or more relative to the surface of the pad, which eliminates the abrupt step that causes stress concentration. This curved/sloped transition distributes the stress more evenly across the surface protective film, preventing crack generation during dicing and sealing processes.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention changes the geometric parameter of the pad structure by forming a sloped side surface with a specific angle (45 degrees or more). This parameter change in the pad profile modifies how stress is distributed to the surface protective film, transforming the stress concentration at a vertical step into a distributed stress pattern along the sloped surface, thereby improving crack resistance.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If the surface protective film is formed to cover the step, then complete coverage is achieved, but stress concentration occurs at the step causing cracks

Engineering Contradiction:

Improvecoverage completeness of surface protective filmVSAvoidstress concentration on surface protective film

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

By forming the pad side surface with a slope angle of 45 degrees or more, the invention eliminates the abrupt vertical step while maintaining continuous coverage of the surface protective film. The sloped surface allows the film to conform smoothly without creating stress concentration points, thus achieving both complete coverage and stress distribution.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention applies a localized structural modification to the pad side surface, creating a sloped region with specific geometric properties (45 degrees or more slope angle). This local quality change in the pad structure directly affects how the surface protective film experiences stress, transforming the harmful stress concentration into a beneficial stress distribution pattern.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS11810869B2Semiconductor device and method of manufacturing the same

Publication Date: 2023.11.07 RENESAS ELECTRONICS CORP

AI summary

A semiconductor device with improved reliability is provided. The semiconductor device is characterized by its embodiments in that sloped portions are formed on connection parts between a pad and a lead-out wiring portion, respectively. This feature suppresses crack formation in a coating area where a part of the pad is covered with a surface protective film.