Passivation Layer Stack to Block Antenna Effect in Semiconductor Pads

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Solution Overview

Problem

High density plasma chemical vapor deposition (HDPCVD) generates charged particles that accumulate in passivation layers, leading to the antenna effect, which damages active components in semiconductor devices by transferring charge through conductive pads.

Innovation Solution

A dielectric layer with lower conformity is formed directly over conductive pads using a deposition process that generates few charged particles, acting as a barrier between the conductive pads and the charged particles, and a passivation layer with higher conformity is deposited using HDPCVD to prevent oxidation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a passivation layer is deposited using HDPCVD to protect conductive pads from oxidation, then the passivation layer provides adequate oxidation protection, but charged particles accumulate in the passivation layer causing the antenna effect that damages active components

Engineering Contradiction:

Improveoxidation protectionVSAvoidantenna effect

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

An intermediate layer is introduced between the conductive pad and the HDPCVD passivation layer. This intermediate layer serves as a mediator that prevents charged particles generated during HDPCVD from reaching and accumulating on the conductive pad, thereby eliminating the antenna effect while allowing the outer passivation layer to provide oxidation protection

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The single passivation layer is segmented into multiple layers: an inner layer deposited by a process that generates minimal charged particles (such as PECVD or ALD), and an outer layer deposited by HDPCVD. This segmentation allows each layer to perform its specific function - the inner layer prevents charged particle accumulation while the outer layer provides oxidation protection

Inventive Principle:

Principle #1Segmentation

2Productivity

If the pitch between conductive pads is decreased to increase device density, then more devices can be integrated, but the passivation layer requires higher conformity to adequately protect the smaller conductive pads

Engineering Contradiction:

Improvedevice densityVSAvoidpassivation layer conformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

Different regions of the passivation structure are assigned different qualities: the inner layer uses a deposition process optimized for conformality (such as ALD or PECVD) to ensure uniform coverage on high-aspect-ratio structures, while the outer layer uses HDPCVD optimized for oxidation protection. This local quality assignment allows each layer to excel at its primary function

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If HDPCVD is used to deposit the passivation layer directly over conductive pads, then the process is simple and efficient, but charged particles are generated and directed toward the conductive pads causing damage

Engineering Contradiction:

Improvedeposition process simplicityVSAvoidcharged particle damage

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

An intermediate barrier layer is deposited between the conductive pad and the HDPCVD passivation layer. This intermediate layer acts as a mediator that blocks charged particles from reaching the conductive pad while allowing the HDPCVD process to proceed with its full oxidation protection benefits. The intermediate layer can be deposited using PECVD or ALD, which are well-established processes that add minimal complexity

Inventive Principle:

Principle #24Intermediary (Mediator)

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 dielectric layer effectively reduces the antenna effect by preventing charge transfer to active devices, while the passivation layer provides adequate protection against oxidation, ensuring the integrity of semiconductor devices.

Implementation Method 1

A dielectric layer is formed directly over the conductive pad... acting as a barrier between the conductive pads and the charged particles

Methodology Applied

Scientific EffectPhysical barrier (dielectric layer):

Implementation Method 2

passivation layers are deposited over the conductive pads... to reduce the risk of oxidation of the conductive pads

Methodology Applied

Scientific EffectOxidation prevention: Oxidation

Implementation Method 3

the passivation layers are formed using a high density plasma chemical vapor deposition process (HDPCVD). HDPCVD generates charged particles

Methodology Applied

Scientific EffectHigh density plasma chemical vapor deposition: Plasma Enhanced Chemical Vapour Deposition

Data Source

PatentUS12002771B2Semiconductor device having a passivation layer and method of making

Publication Date: 2024.06.04 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A semiconductor device includes a conductive pad over an interconnect structure, wherein the conductive pad is electrically connected to an active device. The semiconductor device further includes a dielectric layer over the conductive pad, wherein the dielectric layer has a first conformity. The semiconductor device further includes a passivation layer over the dielectric layer, wherein the passivation layer has a second conformity different from the first conformity.