Back-Side Illumination Semiconductor Package Wiring via Inverted Connection

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Solution Overview

Problem

The packaging technique for back-side illumination image sensors faces complications in the wiring process due to the need for electrical connection with upper connection terminals after the through silicon via process, leading to inefficiencies in light responsiveness and image quality.

Innovation Solution

A semiconductor package is manufactured with a connection terminal in a support substrate bonded to an image sensor substrate, where the through via is filled with solder balls or conductive material to electrically connect the terminal to a printed circuit board, simplifying the wiring process using a damascene process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a through silicon via process is used to connect the image sensor substrate to the support substrate, then electrical connection is achieved, but the wiring process becomes complicated and light responsiveness deteriorates

Engineering Contradiction:

Improveelectrical connectionVSAvoidwiring process

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the connection terminal from the support substrate and exposes it through a via, separating the connection function from the substrate structure. This allows the connection terminal to be directly accessible for solder ball attachment without requiring complex wiring processes through the substrate.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of bringing wiring up through the substrate to connect to pads, the patent inverts the approach by exposing the connection terminal through a via from the bottom side, allowing direct connection from below. This reverses the traditional wiring approach and simplifies the connection process.

Inventive Principle:

Principle #13The other way round (Inversion)

2Adaptability or versatility

If multiple overlying layers are formed on the photodiode in a front illumination structure, then integration is achieved, but light loss increases and light responsiveness deteriorates

Engineering Contradiction:

ImproveintegrationVSAvoidlight loss

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent inverts the traditional front-illumination structure by implementing back-side illumination. Light enters through the bottom side of the substrate where the photodiode is located, avoiding passage through multiple overlying layers. This reversal eliminates light loss from metal routing and intermediate layers while maintaining integration capabilities.

Inventive Principle:

Principle #13The other way round (Inversion)

3Reliability

If the penetration depth of photons is increased to improve light flux conversion, then light responsiveness may improve, but the ability to change light flux to photocharge becomes difficult

Engineering Contradiction:

Improvelight responsivenessVSAvoidlight flux conversion

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies local quality by creating a specific region (via structure) with enhanced conductive properties. The via is filled with conductive material to provide a localized high-conductivity path for photocharge collection, addressing the light flux conversion issue in a specific region rather than requiring uniform changes throughout the substrate.

Inventive Principle:

Principle #3Local quality

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 simplifies the wiring process for back-side illumination image sensors by ensuring reliable electrical connections through the use of solder balls or conductive materials, enhancing the efficiency of light transfer and reducing light interference, thereby improving image quality.

Implementation Method 1

the through via may be filled with at least one solder ball, and the connection terminal in the image sensor substrate and a printed circuit board (PCB) may be electrically connected together

Methodology Applied

Scientific EffectSoldering: Soldering

Implementation Method 2

the conductive material may include a metal material which is filled using electroplating

Methodology Applied

Scientific EffectElectroplating: Electroplating

Data Source

PatentUS9293630B2Semiconductor package and method of forming semiconductor package

Publication Date: 2016.03.22 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A semiconductor package includes a semiconductor substrate which includes a first connection terminal electrically connected to a wiring for signal transfer. The semiconductor package may include a semiconductor support substrate which may be bonded to the semiconductor substrate such that a second connection terminal and the first connection terminal are connected to face each other, and has a through via exposing the second connection terminal.