Decoupling Capacitor Stiffener Reduces IC Carrier Curvature

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Solution Overview

Problem

Integrated circuit (IC) device carriers fabricated with dielectric materials face increased risk of material cracking due to thermal cycling, especially in multi-IC chip carriers with high curvature, leading to strain and potential damage.

Innovation Solution

Incorporating a decoupling capacitor stiffener (DCS) with capacitor structures and insulative material between conductive side bars and capacitor plates, connected via interconnects to provide ground and non-ground potential, which reduces curvature and strain on the carrier, mitigating cracking risks and adding rigidity to resist thermal expansion mismatches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dielectric materials are used to fabricate IC device carriers, then electrical properties are improved, but the risk of material cracking during thermal cycling increases

Engineering Contradiction:

Improveelectrical propertiesVSAvoidmaterial cracking risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent employs a composite structure combining dielectric carrier material with stiffener materials having different mechanical properties. The stiffener is integrated onto the dielectric carrier to create a composite system that maintains the electrical advantages of dielectric materials while adding mechanical reinforcement to prevent cracking during thermal cycling.

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If multiple IC chips are mounted on the carrier, then functionality is enhanced, but the curvature and strain on the carrier increase leading to higher cracking risk

Engineering Contradiction:

Improvemulti-IC chip capabilityVSAvoidcurvature-induced strain

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The stiffener acts as a counterbalancing element that compensates for the curvature and strain induced by mounting multiple IC chips. By positioning the stiffener in specific regions of the carrier, it provides mechanical counter-support that reduces the net curvature and strain on the dielectric material, thereby preventing cracking while maintaining multi-IC functionality.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

3Duration of action of stationary object

If the carrier is made more rigid to resist thermal expansion mismatches, then durability is improved, but the risk of cracking due to increased stiffness increases

Engineering Contradiction:

Improvecarrier durabilityVSAvoidcracking risk from thermal cycling

Core Design Contradiction:

Duration of action of stationary objectVSObject-affected harmful factors

Solution Approach 1:

Rather than making the entire carrier uniformly rigid, the patent applies stiffening elements locally at strategic positions on the dielectric carrier. This localized reinforcement provides the necessary rigidity to resist thermal expansion mismatches in critical areas while allowing other regions to maintain flexibility, thereby reducing overall cracking risk during thermal cycling.

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

The DCS effectively reduces the risk of cracking and strain in IC device carriers by providing decoupling capacitance and stiffness, enhancing the mechanical support and electrical paths, thereby improving the reliability and durability of the carriers.

Implementation Method 1

a capacitor structure between a first conductive side bar and a second conductive size bar. The capacitor structure includes a first capacitor plate directly connected to the first conductive side bar, a second capacitor plate directly connected to the second conductive side bar

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

The risk of cracking increases in multi IC chip carriers due to increased material strain caused by the relatively high curvature of the carrier in the region between the IC chips

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

a decoupling capacitor stiffener (DCS)... which reduces curvature and strain on the carrier, mitigating cracking risks and adding rigidity to resist thermal expansion mismatches

Methodology Applied

Scientific EffectMechanical rigidity: Elasticity

Data Source

PatentUS10756031B1Decoupling capacitor stiffener

Publication Date: 2020.08.25 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

An IC device carrier includes organic substrate layers and wiring line layers therein. To reduce stain of the organic substrate layers and to provide decoupling capacitance, one or more decoupling capacitor stiffeners (DCS) are applied to the top side metallization (TSM) surface of the IC device carrier. The DCS(s) reduce the amount of curvature of the IC device carrier and reduce the strain seen by the organic substrate layers, thereby mitigating the risk for cracks forming and expanding or other damage within the carrier. The DCS(s) also include two or more capacitor plates and provides capacitance to electrically decouple electrical subsystems of the system of which the DCS is apart.