Chip Package Structure for Thin Solder Ball Support

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Solution Overview

Problem

The existing chip package designs face challenges in providing adequate protection and support for solder balls due to insufficient material strength and thickness of the protection layer, leading to issues like peeling or disconnection during grinding and wafer dicing, which affects yield rates.

Innovation Solution

Incorporating a molding compound that surrounds the conductive structure and provides additional support, along with a protection layer that extends to the light transmissive sheet's sidewall, enhancing the chip package's strength and stability, and using a manufacturing method that involves forming a trench in the scribe line to facilitate grinding without layer disconnection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the protection layer is made thinner to reduce overall package thickness, then the package becomes more compact, but the protection layer cannot provide adequate support for solder balls and is prone to peeling during grinding

Engineering Contradiction:

Improvepackage thicknessVSAvoidprotection layer strength

Core Design Contradiction:

Volume of moving objectVSStrength

Solution Approach 1:

The patent uses a composite structure consisting of a protection layer (organic material) and a molding compound (inorganic or different organic material) with different mechanical properties. The molding compound provides rigid support while the protection layer provides surface protection, creating a composite system that achieves both thinness and strength.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The protective structure is divided into two distinct layers: the protection layer directly on the circuit board and the molding compound surrounding the conductive structure. This segmentation allows each layer to be optimized for its specific function - the protection layer for surface protection and the molding compound for structural support.

Inventive Principle:

Principle #1Segmentation

2Strength

If the protection layer is made thicker to provide better support for solder balls, then protection and support are improved, but the overall package thickness increases and manufacturing complexity increases

Engineering Contradiction:

Improveprotection layer strengthVSAvoidpackage thickness

Core Design Contradiction:

StrengthVSVolume of moving object

Solution Approach 1:

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

Inventive Principle:

Principle #1Segmentation

3Stability of the object's composition

If the protection layer is made thicker to prevent peeling during grinding, then layer stability is improved, but the overall package size increases

Engineering Contradiction:

Improvelayer stabilityVSAvoidpackage thickness

Core Design Contradiction:

Stability of the object's compositionVSVolume of moving object

Solution Approach 1:

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The molding compound is formed to surround the conductive structure before the final packaging steps. This preliminary formation of the supporting structure prevents layer peeling during subsequent grinding and dicing operations, ensuring layer stability before the actual packaging is completed.

Inventive Principle:

Principle #10Preliminary action

4Ease of manufacture

If conventional BGA process is used with patterned protection layer, then manufacturing process is simpler, but solder ball support is insufficient and yield rate decreases

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidsolder ball support

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The molding compound acts as an intermediary structure between the protection layer and the external environment. It provides mechanical support to the solder balls and conductive structures, mediating the forces applied during handling and mounting, thereby improving reliability without complicating the manufacturing process.

Inventive Principle:

Principle #24Intermediary (Mediator)

5Productivity

If wafer dicing is performed without adequate support structure, then manufacturing efficiency is maintained, but layer peeling and disconnection occur reducing yield rate

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidyield rate

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The molding compound provides a cushioning effect by surrounding the conductive structure, absorbing mechanical stresses during wafer dicing and grinding operations. This beforehand cushioning prevents layer disconnection and peeling, maintaining both manufacturing efficiency and high yield rates.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS20250316548A1Chip package and manufacturing method thereof

Publication Date: 2025.10.09 XINTEC INC

AI summary

A chip package includes a light transmissive sheet, a semiconductor substrate, an isolation layer, a redistribution layer, a protection layer, a conductive structure, and a molding compound. The semiconductor substrate is located on the light transmissive sheet. The isolation layer is located on a surface of the semiconductor substrate facing away from the light transmissive sheet. The redistribution layer is located on the isolation layer. The redistribution layer is located in the protection layer. The conductive structure is located on the redistribution layer in the protection layer. The molding compound is located on the protection layer and surrounds the conductive structure. A surface of the molding compound facing away from the protection layer is coplanar with a surface of the conductive structure facing away from the redistribution layer.