Polyimide Semiconductor Packaging Material for Low-Stress 3D Integration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current semiconductor packaging materials face challenges such as high cure temperatures, residual stress, moisture absorption, and thermal mismatch, which are not adequately addressed by traditional materials like polyimides, epoxies, and BCB, leading to issues like warpage and delamination in next-generation 3D integration applications.
Innovation Solution
Development of novel polyimide polymers formed from specific diamines, tetracarboxylic acid dianhydrides, and reactive functional compounds, which can be processed at lower temperatures with reduced shrinkage and stress, and are soluble in semiconductor-friendly solvents, enabling flexible coating methods like inkjet technology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polyimides are used for packaging, then excellent electrical, mechanical and thermal properties are achieved, but high cure temperatures (>350°C) and high post-cure shrinkage occur
Solution Approach 1:
The patent modifies the chemical structure of polyimide by incorporating specific diamine components ( Structures (Ia), (Ib), and (II)) and tetracarboxylic acid dianhydride components to fundamentally change the curing behavior. This structural parameter change enables the material to cure at lower temperatures (200-300°C) while preserving the excellent electrical, mechanical and thermal properties that make polyimide suitable for semiconductor packaging
2Reliability
If conventional polyimides are used for packaging, then excellent electrical, mechanical and thermal properties are achieved, but high levels of moisture absorption occur
Solution Approach 1:
The patent creates a composite polyimide system by combining specific diamine components (including indane-based diamines of Structures (Ia) and (Ib) with rigid aromatic structures) and tetracarboxylic acid dianhydride components. This composite molecular structure provides both the desired electrical, mechanical and thermal properties while the dense crosslinked network formed by the specific component ratios reduces moisture absorption pathways
3Strength
If conventional polyimides are used for packaging, then material strength is achieved, but high residual stress and wafer bowing occur
Solution Approach 1:
The patent changes the shrinkage parameter by modifying the polyimide molecular structure with specific diamine and dianhydride components. This structural modification reduces post-cure shrinkage to below 3%, which directly reduces residual stress development during curing and prevents wafer bowing while maintaining adequate material strength for packaging applications
Solution Approach 2:
The patent applies preliminary anti-action by designing the polyimide composition to inherently minimize shrinkage stress development during the curing process. The specific diamine and dianhydride component selection creates a curing reaction that proceeds with minimal volume change, preemptively preventing the residual stress and wafer bowing problems that would otherwise occur with conventional polyimides
4Length of moving object
If thinned silicon wafers (20 μm) are used for 3D integration, then vertical integration requirements are satisfied, but extreme fragility occurs
Solution Approach 1:
The patent provides beforehand cushioning by creating a low-stress packaging environment through the specially formulated polyimide composition. The minimal residual stress generated by this polyimide system acts as a cushioning effect that protects fragile thinned wafers (20 μm) from stress-induced damage during and after the packaging process, enabling successful 3D integration without compromising wafer integrity
5Reliability
If packaging materials with low residual stress and low CTE are used, then wafer protection is improved, but poor solubility and processability occur
Solution Approach 1:
The patent changes the solubility parameter by selecting specific diamine components (including indane-based diamines with Structures (Ia) and (Ib)) and tetracarboxylic acid dianhydride components that create a polyimide structure soluble in semiconductor-friendly solvents. This parameter change enables solution processing and inkjet deposition while maintaining the low residual stress and low CTE properties necessary for wafer protection in advanced packaging
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 new polyimide polymers provide a solution with minimal residual stress, low thermal expansion, and improved processability, meeting the stringent requirements for advanced packaging materials in next-generation semiconductor devices, ensuring reliable performance and integration.
Implementation Method 1
conventional polyimides include high cure temperatures (>350° C.), high post-cure shrinkage
Implementation Method 2
high post-cure shrinkage which leads to cured polyimide films having high residual stress
Implementation Method 3
high levels of moisture absorption
Implementation Method 4
A packaging material with a high CTE creates a large thermal mismatch with the underlying substrate
Data Source
AI summary
A polyimide polymer that includes the reaction product of: (a) at least one diamine selected from the group consisting of a diamine of Structure (Ia) and a diamine of Structure (Ib),(b) at least one diamine of Structure (II),(c) at least one tetracarboxylic acid dianhydride, and optionally (d) at least one compound containing a first functional group reactive with an amine or an anhydride and at least one second functional group selected from the group consisting of a substituted or unsubstituted alkenyl group and a substituted or unsubstituted alkynyl group. Each variable in the above formulas is defined in the specification.