Semiconductor Pad Structure with Nickel and Palladium Layers

Solution Overview

Problem

The scaling down of semiconductor devices poses challenges in achieving improved quality, yield, performance, reliability, and reduced complexity, particularly in the design of pad structures and passivation layers.

Innovation Solution

A semiconductor device design featuring a pad structure with a nickel-based pad bottom conductive layer and a palladium or cobalt-based pad top conductive layer, integrated within multiple passivation layers, including a polyimide-based bonding opening, to enhance electrical coupling and reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the dimensions of semiconductor devices are scaled down, then computing ability is improved, but quality, yield, performance and reliability deteriorate

Engineering Contradiction:

Improvecomputing abilityVSAvoiddevice reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The pad structure is divided into multiple conductive layers (first pad conductive layer, second pad conductive layer, third pad conductive layer) with different materials and functions. Each layer serves a specific purpose: the first layer provides electrical connection, the second layer enhances adhesion and prevents diffusion, and the third layer provides bonding capability. This segmentation allows the device to maintain reliability despite scaling down dimensions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs a composite pad structure using multiple materials including nickel, copper, palladium, and cobalt in different layers. This composite approach combines the advantages of each material: nickel for electrical conductivity, copper for low resistance, palladium for adhesion, and cobalt for diffusion prevention. The multi-material composition enables the device to achieve both small dimensions and high reliability.

Inventive Principle:

Principle #40Composite materials

2Productivity

If the dimensions of semiconductor devices are scaled down, then computing ability is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvecomputing abilityVSAvoidpad structure complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The pad structure is divided into multiple conductive layers (first pad conductive layer, second pad conductive layer, third pad conductive layer) with different materials and functions. Each layer serves a specific purpose: the first layer provides electrical connection, the second layer enhances adhesion and prevents diffusion, and the third layer provides bonding capability. This segmentation allows the device to maintain reliability despite scaling down dimensions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a passivation process before forming the pad structure, where a pad opening is created in the passivation layer and the underlying conductive line is exposed. This preliminary preparation simplifies subsequent steps by pre-defining the pad structure location and ensuring proper electrical connections are established before adding the multi-layer pad structure.

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If conventional pad structures are used, then manufacturing is simpler, but electrical coupling and reliability are insufficient

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidelectrical coupling

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent employs a composite pad structure using multiple materials including nickel, copper, palladium, and cobalt in different layers. This composite approach combines the advantages of each material: nickel for electrical conductivity, copper for low resistance, palladium for adhesion, and cobalt for diffusion prevention. The multi-material composition enables the device to achieve both small dimensions and high reliability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

Instead of using a single-layer pad structure, the patent transitions to a multi-layer vertical structure. The first pad conductive layer is formed in the passivation layer, the second pad conductive layer is formed on top of it, and the third pad conductive layer is formed on the second layer. This dimensional transition from 2D to 3D structure enhances electrical coupling and reliability while maintaining manufacturing feasibility.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS11552081B2Method for fabricating a semiconductor device and the same

Publication Date: 2023.01.10 NAN YA TECH

AI summary

The present application discloses a method for fabricating a semiconductor device with a pad structure. The method includes providing a substrate, forming a capacitor structure above the substrate, forming a plurality of passivation layers above the capacitor structure, forming a pad opening in the plurality of passivation layers, performing a passivation process comprising soaking the pad opening in a precursor, and forming a pad structure in the pad opening. The precursor is dimethylaminotrimethylsilane or tetramethylsilane. Forming the pad structure in the pad opening comprises forming a pad bottom conductive layer comprising nickel in the pad opening and forming a pad top conductive layer on the pad bottom conductive layer. The pad top conductive layer comprises palladium, cobalt, or a combination thereof.