Noncontact Coating for Thin Adhesive Layers in Semiconductor Packaging
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Solution Overview
Problem
The formation of thin adhesive layers on semiconductor elements is challenging due to issues with void creation and thickness uniformity in existing coating methods, particularly in stacked structures, which affects production yield and precision in semiconductor packaging.
Innovation Solution
A method using a noncontact coating device to apply a thermosetting adhesive composition with two reactive components, one hardening at lower and one at higher temperatures, along with an organic solvent, to form a stable and thin adhesive layer, ensuring precise coating and preventing void formation during thermal compression bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional dispensing or stamping methods are used to form adhesive layers, then the coating process is simple, but the adhesive layer thickness cannot be controlled uniformly at several μm and coating amount fluctuates
Solution Approach 1:
The patent replaces conventional mechanical coating methods (dispensing, stamping) with a noncontact coating device that uses a different physical mechanism. This substitution enables precise thickness control at several μm without the fluctuations inherent in mechanical contact methods, directly resolving the contradiction between manufacturing precision and device complexity.
2Manufacturing precision
If filmy adhesive sheets are used to control thickness uniformly, then the adhesive layer can be made thin and uniform, but the sheets are difficult to handle on silicon wafers and manufacturing cost increases
Solution Approach 1:
The patent changes the physical state and parameters of the adhesive from pre-formed filmy sheets to a liquid composition that is coated in situ. This parameter change allows the adhesive to be applied as a liquid that can be precisely controlled during coating, then cured to form the final layer, eliminating handling difficulties and reducing manufacturing costs while maintaining thickness uniformity.
Solution Approach 2:
The patent introduces an organic solvent as an intermediary medium to dissolve the thermosetting composition, enabling it to be applied as a liquid coating. This intermediary allows precise coating control and easy removal through evaporation, replacing the need for handling solid filmy sheets and reducing manufacturing complexity.
3Volume of moving object
If thin semiconductor elements are stacked to achieve downsizing, then the semiconductor product size is reduced, but voids are created at adhesive layer interface due to warping and air incorporation
Solution Approach 1:
The patent utilizes parameter changes through dual-temperature hardening reactions. The first hardening reaction occurs at lower temperature to initially set the adhesive layer, while the second hardening reaction occurs at higher temperature during thermal compression bonding to fully cure the adhesive and eliminate voids. This two-stage parameter change resolves the reliability issue while maintaining the downsized structure.
Solution Approach 2:
The patent applies preliminary action by forming the adhesive layer with controlled thickness and uniform coating before the stacking process. The noncontact coating device ensures precise adhesive distribution prior to assembly, preventing void formation at interfaces during subsequent stacking and thermal compression bonding, thus maintaining both compact size and high reliability.
4Length of moving object
If adhesive layer thickness is reduced to several μm for extreme thinning, then the semiconductor element thickness is reduced, but voids are easily incorporated and coating precision becomes difficult to achieve
Solution Approach 1:
The patent replaces mechanical contact coating methods with a noncontact coating device, substituting the mechanical system with a different physical approach. This substitution enables precise coating at several μm thickness without the contact-induced variations and defects, achieving both extreme thinning and high coating precision simultaneously.
Solution Approach 2:
The patent uses organic solvent as an intermediary to deliver the thermosetting composition in a controllable liquid state. The solvent allows precise coating thickness control at several μm, then evaporates cleanly without residue, preventing void formation while enabling the extreme thinning required for advanced semiconductor applications.
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 enables the formation of a thin, uniform adhesive layer with advanced properties such as heat-resistance, flatness, and moisture-proof reliability, enhancing semiconductor packaging by preventing void creation and improving production yield.
Implementation Method 1
selectively coating, on a surface to be bonded, an adhesive composition containing a thermosetting composition and an organic solvent using a noncontact coating device
Implementation Method 2
removing the organic solvent from the adhesive composition coated on the surface to be bonded
Implementation Method 3
the thermosetting composition has a hardening property so as to exhibit two kinds of reaction temperatures
Implementation Method 4
the thermal compression bonding process of the semiconductor elements with adhesive agents thereon
Data Source
AI summary
In a forming method of an adhesive layer including the steps of selectively coating, on a surface to be bonded, an adhesive composition containing a thermosetting composition and an organic solvent using a noncontact coating device; and removing the organic solvent from the adhesive composition coated on the surface to be bonded and in a forming method of an adhesive layer characterized in the thermosetting composition has a hardening property so as to exhibit two kinds of reaction temperatures, the adhesive composition comprising an epoxy resin and an epoxy curing agent which are reacted through a first hardening reaction exhibiting a first DSC peak within a temperature range of 100 to 160° C. and a second hardening reaction relating to a self-polymerization of the epoxy resin and exhibiting a second DSC peak within a temperature range of 140 to 200° C.