TSV Buffer Layer for Planar Surface and Bonding

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional through silicon via (TSV) technology faces electrical connection issues due to concave surfaces or dishing at the top of TSV caps, leading to poor bonding and increased RC delay and power consumption in three-dimensional integrated circuits.

Innovation Solution

A method involving the deposition of a thin nickel buffer layer with a different crystal structure above the copper seed layer to prevent the transfer of the crystalline structure, minimizing dishing and maintaining conductivity, along with reducing the thickness of the adhesive layer to enhance the planarity of the TSV cap surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional TSV cap structure is used, then the TSV can be formed, but dishing occurs at the top surface leading to poor bonding

Engineering Contradiction:

Improveplanarity of TSV cap surfaceVSAvoidbonding quality

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

A buffer layer is introduced as an intermediary between the copper seed layer and the TSV cap layers. This buffer layer has a different crystal structure that prevents the transfer of columnar grain growth to the TSV cap, thereby eliminating dishing and ensuring a planar surface for reliable bonding

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The crystal structure parameter of the TSV cap is changed by depositing it on a buffer layer with a different crystal structure. This parameter change prevents the formation of columnar grains and dishing, achieving a planar surface without compromising the TSV formation

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If the photoresist layer is removed after patterning, then the TSV cap structure is completed, but residual photoresist causes defects

Engineering Contradiction:

Improveprocess simplicityVSAvoidcleanliness of TSV cap surface

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The photoresist layer is removed immediately after patterning the TSV cap structure, before subsequent processing steps. This preliminary removal action prevents photoresist contamination and defects in later stages, while maintaining process simplicity through integrated timing

Inventive Principle:

Principle #10Preliminary action

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

The solution effectively reduces dishing, improves bonding, and maintains low resistance, resulting in enhanced electrical conductivity and reduced complexity in interconnection routing, thereby addressing the limitations of conventional TSV technology.

Implementation Method 1

deposition of a thin nickel buffer layer with a different crystal structure above the copper seed layer to prevent the transfer of the crystalline structure, minimizing dishing

Methodology Applied

Scientific EffectCrystal structure mismatch: Crystallisation

Implementation Method 2

maintains low resistance, resulting in enhanced electrical conductivity

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS9281274B1Integrated circuit through-substrate via system with a buffer layer and method of manufacture thereof

Publication Date: 2016.03.08 JCET SEMICON (SHAOXING) CO LTD

AI summary

An integrated circuit substrate via system, and method of manufacture therefor, includes: a substrate having a substrate via in the substrate; a buffer layer patterned over the substrate via, the buffer layer having a planar surface; and a substrate via cap patterned over the buffer layer, the substrate via cap having a planar surface based on the planar surface of the buffer layer.