RDL Side and Back Protection for Substrate Warpage Control

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Solution Overview

Problem

Semiconductor devices face challenges with substrate warpage and damage on the opposing major surface, which can lead to reliability issues and manufacturing complexities due to the lack of effective side and back protection for the redistribution layer (RDL).

Innovation Solution

A method and structure for forming a redistribution layer (RDL) with integrated side and back protection using multiple layers of conductive and insulating materials, including the deposition of conductive layers and insulating layers such as silicon dioxide, polyimide, and epoxy resin, to provide structural support and protection against warpage and damage, enhancing interconnect functionality and manufacturing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If RDL is formed on substrate for electrical interconnect, then electrical interconnect functionality is achieved, but substrate is subject to damage and warpage

Engineering Contradiction:

Improveelectrical interconnect reliabilityVSAvoidsubstrate stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The protection system is segmented into multiple functional layers: a first protective layer applied to the back surface of the substrate, and a second protective layer formed around the RDL. This segmentation allows each layer to perform its specific protective function independently, with the first layer preventing back surface damage and the second layer protecting the RDL structure, thereby resolving the contradiction between maintaining electrical interconnect functionality and preventing substrate warpage and damage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first protective layer is applied beforehand to the back surface of the substrate before RDL formation, providing preemptive protection against warpage and damage. This prior cushioning approach prevents substrate instability from developing, thereby maintaining both the electrical interconnect functionality and substrate stability throughout the manufacturing process and device operation.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Strength

If multiple layers of conductive and insulating materials are deposited for RDL and protection, then structural support and protection are provided, but manufacturing complexity increases

Engineering Contradiction:

Improvestructural support strengthVSAvoidmanufacturing process complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The protective layers serve multiple functions simultaneously: the first protective layer provides mechanical support to prevent substrate warpage, while the second protective layer protects the RDL structure and provides electrical isolation. By designing these layers with multi-functionality, the patent achieves strong structural support without requiring additional specialized components, thereby reducing overall manufacturing complexity despite the multi-layer structure.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The protective layers are merged with the RDL structure itself, forming an integrated protective-RDL composite structure. The second protective layer is formed around the RDL in a continuous process, combining the RDL formation and protection steps into a single manufacturing sequence. This merging approach reduces the number of separate manufacturing steps and simplifies the overall process while maintaining strong structural support.

Inventive Principle:

Principle #5Merging (Combining)

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 provides reliable protection for semiconductor devices by preventing warpage and damage, improving interconnect accuracy and manufacturing efficiency, and increasing the reliability of semiconductor devices through efficient side and back protection for the RDL.

Implementation Method 1

conductive layers and insulating layers such as silicon dioxide, polyimide, and epoxy resin, to provide structural support

Methodology Applied

Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Implementation Method 2

insulating layers such as silicon dioxide, polyimide, and epoxy resin

Methodology Applied

Scientific EffectChemical Vapour Deposition: Chemical Vapour Deposition

Data Source

PatentUS20230343668A1Semiconductor Packages and Methods of Forming RDL and Side and Back Protection for Semiconductor Device

Publication Date: 2023.10.26 UTAC HEADQUARTERS PTE LTD

AI summary

A semiconductor device has a substrate and a first insulating layer formed over a first major surface of the substrate. A first redistribution layer is formed over the first insulating layer. A second insulating layer is formed over the first redistribution layer. A second redistribution layer can be formed over the second insulating layer, and a third insulating layer can be formed over the second redistribution layer. A protection layer is formed over a second major surface of the substrate for warpage control. A conductive layer is formed over the first redistribution layer, and a bump is formed over the conductive layer. An under bump metallization can be formed under the bump. The protection layer extends over a side surface of the substrate between the first major surface and second major surface. The protection layer further extends over a side surface of the first insulating layer.