Die Stack Arrangement Using DAF Tape and Spacer Layer

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Solution Overview

Problem

Conventional die stacking processes are not directly applicable for MEMS components, requiring them to be the smallest die in the stack, and involve complex and costly front-end technologies like wafer bonding or film lamination, which result in large stack heights and mechanical damage risks.

Innovation Solution

A die stack arrangement using a DAF tape element with a spacer layer that includes a bleed stopper structure with cutouts to inhibit capillary creeping of the DAF material, allowing the MEMS component to be exposed and securely positioned on a base substrate, enabling reliable cavity formation and reduced stack height.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional die stacking processes are used with MEMS components, then the MEMS component must be the smallest die in the stack, but this limits the adaptability and functionality of the stack arrangement

Engineering Contradiction:

Improveadaptability of MEMS component size in stackVSAvoidcomplexity of stacking process

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention introduces a spacer layer with structured support elements that segment the bonding process, allowing the MEMS component to be bonded independently without requiring it to be the smallest die. The spacer layer creates defined bonding regions that facilitate the attachment of larger MEMS components to the substrate before stacking.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The spacer layer acts as an intermediary element between the substrate and the MEMS component, providing mechanical support and defining the bonding interface. This intermediary structure enables the bonding of larger MEMS components that would otherwise be incompatible with conventional stacking processes.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If wafer bonding or film lamination is used to protect MEMS structure, then the MEMS structure is protected against glue bleeding and mechanical damage, but the stack height increases and the process becomes more complex and costly

Engineering Contradiction:

Improveprotection of MEMS structureVSAvoidcomplexity and cost of front end technology

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts the protection function from the traditional cover lid structure and integrates it into the spacer layer with structured support elements. This eliminates the need for separate wafer bonding or film lamination processes while maintaining protection against glue bleeding and mechanical damage.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The spacer layer combines multiple functions: it provides mechanical support, defines the bonding interface, and protects the MEMS structure from glue bleeding and mechanical damage. This merging of functions eliminates the need for separate protective structures and simplifies the overall process.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If a cover lid is applied over the MEMS structure to protect it, then the MEMS structure is protected, but the resulting package height increases

Engineering Contradiction:

Improveprotection of MEMS structureVSAvoidstack height

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

The spacer layer combines the protection function with the structural support function, eliminating the need for a separate cover lid. This integration reduces the overall stack height while maintaining protection of the MEMS structure against glue bleeding and mechanical damage.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The invention removes the cover lid from the stack arrangement by integrating its protective function into the spacer layer. This extraction of the protective function reduces the stack height while maintaining the necessary protection for the MEMS structure.

Inventive Principle:

Principle #2Taking out (Extraction)

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

Enables efficient and cost-effective die stacking of MEMS components without the need for them to be the smallest die, reducing package height and enhancing mechanical stability while preventing mechanical damage and glue bleeding.

Implementation Method 1

the bleed stopper structure having the cutouts is configured to inhibit capillary crimping or flowing of a DAF material of the DAF tape element in a partly liquefied state

Methodology Applied

Scientific EffectCapillary effect: Capillary Action

Data Source

PatentUS11342298B2Die stack arrangement comprising a die-attach-film tape and method for producing same

Publication Date: 2022.05.24 INFINEON TECHNOLOGIES AG

AI summary

A device includes a base substrate with a sensor component arranged thereon; a spacer layer on the base substrate, wherein the spacer layer is structured in order to predefine a cavity region, in which the sensor component is arranged in an exposed fashion on the base substrate, and a DAF tape element (DAF=Die-Attach-Film) on a stack element, wherein the DAF tape element mechanically fixedly connects the stack element to the spacer layer arranged on the base substrate and to obtain the cavity region.