Package Substrate Reinforcing Plate Warpage Control

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Solution Overview

Problem

Conventional thin package substrates face challenges in maintaining structural strength and flatness, especially during high-temperature bumping processes, due to reduced thickness which compromises electrical signal transmission speed and warpage issues.

Innovation Solution

A package substrate design incorporating a reinforcing plate with an insulating film and metal plate, which is bonded to the circuit board to enhance strength and prevent warpage, featuring conductive channels for electrical connectivity and heat dissipation, while using a coreless circuit board with plated through holes for efficient signal transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the thickness of the core layer is reduced to accelerate electrical signal transmission, then the electrical transmission speed is improved, but the structural strength and flatness of the substrate deteriorate

Engineering Contradiction:

Improveelectrical transmission speedVSAvoidstructural strength

Core Design Contradiction:

SpeedVSStrength

Solution Approach 1:

The patent combines a thin core layer (for high-speed signal transmission) with a reinforcing plate made of rigid material (for structural support). This composite structure allows the thin substrate to maintain both high electrical transmission speed and adequate structural strength, resolving the contradiction between speed and strength requirements.

Inventive Principle:

Principle #40Composite materials

2Length of moving object

If the thickness of the core layer is reduced to meet thin substrate requirements, then the substrate thickness is improved, but the warpage during high-temperature bumping process worsens

Engineering Contradiction:

Improvesubstrate thicknessVSAvoidflatness during manufacturing

Core Design Contradiction:

Length of moving objectVSStability of the object's composition

Solution Approach 1:

The patent uses a composite structure combining a thin core layer with a reinforcing plate of rigid material. The reinforcing plate provides thermal stability and dimensional control during high-temperature bumping processes, preventing warpage while allowing the overall substrate to remain thin for high-speed signal transmission.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the physical parameters of the substrate by introducing a reinforcing plate with specific mechanical properties (high rigidity, low thermal expansion). This parameter change enables the thin substrate to maintain flatness during manufacturing processes while achieving the desired thinness for high-speed performance.

Inventive Principle:

Principle #35Parameter changes

3Strength

If a copper foil substrate with greater thickness is used to enhance strength, then the structural strength is improved, but the electrical transmission speed is reduced

Engineering Contradiction:

Improvestrength and supportabilityVSAvoidelectrical transmission speed

Core Design Contradiction:

StrengthVSSpeed

Solution Approach 1:

The patent segments the substrate structure into two functional parts: a thin core layer (40-80 μm) for high-speed electrical transmission and a separate reinforcing plate for structural support. This segmentation allows each component to be optimized independently - the core layer for speed and the reinforcing plate for strength - resolving the contradiction between these two requirements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent creates a composite structure where a thin core layer is combined with a reinforcing plate made of rigid material. This composite approach enables the substrate to achieve both high electrical transmission speed (through the thin core) and adequate structural strength (through the reinforcing plate), eliminating the need to choose between speed and strength.

Inventive Principle:

Principle #40Composite materials

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 effectively enhances the structural integrity and flatness of thin substrates, prevents warpage during high-temperature processes, and improves heat dissipation and electromagnetic interference shielding, meeting manufacturing requirements.

Implementation Method 1

A first surface of the reinforcing plate is disposed on the circuit board for resisting the warpage of the circuit board

Methodology Applied

Scientific EffectMechanical support: Mechanical Force

Implementation Method 2

one end of the conductive channel is located in the opening and electrically connected to the first contact, and the other end of the conductive channel is located on a second surface of the reinforcing plate to form a bonding pad

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

the surfaces of the metal plate are covered by the insulating film

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Data Source

PatentUS7772703B2Package substrate

Publication Date: 2010.08.10 UNIMICRON TECH CORP

AI summary

A package substrate including a circuit board, a reinforcing plate and at least one conductive channel is provided. A first surface of the reinforcing plate is disposed on the circuit board for resisting the warpage of the circuit board. The reinforcing plate has an opening corresponding to a first contact of the circuit board exposed thereon. In addition, one end of the conductive channel is located in the opening and electrically connected to the first contact, and the other end of the conductive channel is located on a second surface of the reinforcing plate to form a bonding pad.