Dual-Side Plastic Encapsulation for Semiconductor Substrate Warpage Control

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Solution Overview

Problem

The existing plastic encapsulation techniques face issues with substrate warpage and distortion due to gravity and component weight, requiring large support spaces that occupy layout space and may still result in substrate distortion, necessitating thicker substrates to prevent distortion.

Innovation Solution

A method employing surface mounting technology (SMT) for both surfaces of a component, where the second surface acts as a support plane without separate supports, allowing for vacuum-assisted resin injection and solidification on both surfaces within a mold, eliminating the need for additional support structures and enabling reduced substrate thickness and increased layout density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If large support spaces are reserved on the substrate to prevent warpage and distortion during plastic injection, then substrate stability is improved, but the layout space for components is reduced

Engineering Contradiction:
Improvesubstrate stabilityVSAvoidlayout space
Core Design Contradiction:
Stability of the object's compositionVSArea of stationary object

Solution Approach 1:

The patent transitions from single-sided encapsulation to dual-sided encapsulation, utilizing the third dimension (both surfaces of the substrate) for component placement. This allows components to be distributed on both the first and second surfaces, effectively doubling the usable layout area without requiring larger support spaces on a single surface.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The encapsulation process is divided into two separate molding operations: first surface encapsulation and second surface encapsulation. Each surface is processed independently with its own molding cycle, allowing optimized support structures for each surface rather than requiring excessive support space on one surface.

Inventive Principle:
Principle #1Segmentation

2Strength

If the substrate is thickened to prevent distortion during encapsulation, then substrate strength is improved, but the overall device size and complexity increase

Engineering Contradiction:
Improvesubstrate strengthVSAvoiddevice complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The substrate is pre-strengthened through lamination with reinforcement layers (such as fiberglass or metal sheets) before the encapsulation process. This preliminary reinforcement provides the necessary structural strength to prevent distortion during molding without requiring the substrate itself to be thicker, thus maintaining device compactness.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The substrate is constructed as a composite structure combining the base substrate material with reinforcement layers. This composite construction provides enhanced mechanical strength and dimensional stability during the encapsulation process while keeping the overall device profile thin and simple.

Inventive Principle:
Principle #40Composite materials

3Manufacturing precision

If separate support structures are added to prevent substrate bending, then manufacturing precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvemanufacturing precisionVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The support function is merged with the mold structure itself. The mold includes integrated support elements (such as support columns or ribs) that provide the necessary support during encapsulation without requiring separate, additional support structures. This integration maintains manufacturing precision while reducing device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The mold structure is designed to be self-supporting during the encapsulation process. The mold's own structural features provide the necessary support to prevent substrate bending, eliminating the need for separate support structures and simplifying the overall device design.

Inventive Principle:
Principle #25Self-service

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 effectively prevents substrate warpage and distortion, reduces substrate thickness, and enhances component layout density while lowering costs by eliminating the need for additional support structures and allowing dual-surface encapsulation, resulting in a more efficient and cost-effective encapsulation process.

Implementation Method 1

vacuuming the second surface through a vacuum suction hole at the bottom of the lower mold to keep the plane of the second surface smooth

Methodology Applied
Scientific EffectVacuum: Vacuum

Data Source

PatentEP2565913B1Method for encapsulating of a semiconductor
Publication Date: 2019.03.20 HUAWEI DEVICE CO LTD
  • EP2565913B1 patent drawingFigure 1~2
  • EP2565913B1 patent drawingFigure 3~4
  • EP2565913B1 patent drawingFigure 5~6

AI summary

Embodiments of the present invention disclose a method for encapsulating a component with plastic and its encapsulation structure, which belong to the plastic encapsulation technology field. The method includes: processing, by using the surface mounting technology, a first surface of a part to be encapsulated with plastic and/or performing die bonding on the first surface; encapsulating, with plastic, the first surface of the part to be encapsulated with plastic which has undergone the processing performed by using the surface mounting technology and/or has undergone the die bonding; processing, by using the surface mounting technology, a second surface of the part to be encapsulated with plastic the first surface of which has undergone the encasulating with plastic and/or performing die bonding in the second face; and encapsulating, with plastic, the second surface of the part to be encapsulated with plastic which has undergone the processing performed by using the surface mounting technology and/or has undergone the die bonding. This encapsulation structure includes a substrate, where components are fixed on an upper surface and a lower surface of the substrate, and the components on the upper surface and lower surface are all encapsulated with plastic in seal. The embodiments solve the problem of warpage and distortion on the substrate: The component is encapsulated with plastic on both surfaces so that both surfaces have characteristics such as dustproof and waterproof, and good internal sealability.