Through Electrode Density and Reliability in Solid-State Image Sensors

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Solution Overview

Problem

Existing solid-state image-capturing devices face challenges in increasing the density and reliability of through electrodes due to issues with step disconnections and solder mask coatability, particularly with high aspect ratio through electrodes formed by conventional dry etching methods.

Innovation Solution

A solid-state image-capturing device design featuring a common opening portion with through electrodes that penetrate to electrode pads, where the aspect ratio of through electrodes is maintained at 1.5 or less, allowing for vertical side surfaces and reduced processing time, thereby preventing recesses and overhangs, and a manufacturing method involving chemical mechanical polishing and dry etching to form these electrodes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the aspect ratio of through electrodes is increased to improve density, then the density of through electrodes is improved, but step disconnections and poor solder mask coatability occur

Engineering Contradiction:

Improvedensity of through electrodesVSAvoidstep disconnection and solder mask coatability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The through electrode formation process is segmented into two distinct stages: first forming a common opening portion with a first aspect ratio, then forming individual through portions with a second aspect ratio. This segmentation allows each stage to be optimized independently, achieving high density while maintaining reliability by controlling aspect ratios separately for each formation stage.

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If conventional dry etching is used to form through electrodes, then the manufacturing process is simple, but processing time becomes long and vertical side surfaces cannot be formed

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidprocessing time

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The etching process is segmented into two sequential dry etching operations: first etching the common opening portion to a intermediate depth, then etching individual through portions to complete penetration. This segmentation reduces the processing time for each individual through electrode while maintaining vertical side surfaces, thereby improving productivity without sacrificing manufacturing simplicity.

Inventive Principle:

Principle #1Segmentation

3Quantity of substance

If a common opening portion is shared by multiple through electrodes, then the density of through electrodes increases, but the complexity of electrode formation increases

Engineering Contradiction:

Improvedensity of through electrodesVSAvoidelectrode formation structure

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The electrode formation structure is segmented into a common opening portion and individual through portions. This segmentation allows the common opening to serve multiple electrodes (increasing density) while the individual through portions maintain simple, distinct formation processes that avoid excessive complexity in the overall structure.

Inventive Principle:

Principle #1Segmentation

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 approach enhances the yield and reliability of through electrodes while increasing their density by sharing a common opening portion among multiple electrodes, improving the coatability of the solder mask and preventing disconnections.

Implementation Method 1

a manufacturing method involving chemical mechanical polishing and dry etching to form these electrodes

Methodology Applied

Scientific EffectChemical mechanical polishing:

Implementation Method 2

the through electrode is formed by photolithography and dry etching, and the depth of the through electrodes becomes from 5 μm to 300 μm

Methodology Applied

Scientific EffectDry etching:

Data Source

PatentUS11482557B2Solid-state image-capturing device, semiconductor apparatus, electronic apparatus, and manufacturing method

Publication Date: 2022.10.25 SONY SEMICON SOLUTIONS CORP

AI summary

Provided are a solid-state image-capturing device, a semiconductor apparatus, an electronic apparatus, and a manufacturing method that enable improvement in reliability of through electrodes and increase in density of through electrodes. A common opening portion is formed including a through electrode formation region that is a region in which the plurality of through electrodes electrically connected respectively to a plurality of electrode pads provided on a joint surface side from a device formation surface of a semiconductor substrate is formed. A plurality of through portions is formed so as to penetrate to the plurality of respective electrode pads in the common opening portion, and wiring is formed along the common opening portion and the through portions from the electrode pads to the device formation surface corresponding to the respective through electrodes. The present technology can be applied to a layer-type solid-state image-capturing device, for example.