Porous Substrate Protection via Organic Liquid Condensation
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Solution Overview
Problem
Porous materials, particularly low-k dielectrics, suffer damage during plasma etching due to active plasma radicals penetrating and altering their composition and porosity, leading to capacitance issues and material degradation in microelectronics fabrication.
Innovation Solution
A method involving contacting the porous material with an organic gas that condenses into a liquid within its pores, followed by plasma etching, where the organic liquid is evaporated in cycles to protect the material and prevent damage, allowing for efficient filling of micropores and reducing plasma-induced fluorine diffusion and VUV damage, while maintaining non-cryogenic temperatures and moderate deprotecting temperatures for cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma etching is performed on porous material, then etching capability is improved, but material damage increases due to plasma radicals penetrating pores
Solution Approach 1:
A liquid compound is introduced as an intermediary substance that fills the pores of the porous material before plasma etching. This liquid acts as a protective mediator, preventing plasma radicals from penetrating and damaging the porous structure while allowing the etching process to proceed on the surface.
Solution Approach 2:
The liquid compound is applied to fill the pores before the plasma etching process begins. This preliminary action ensures that the protective barrier is in place prior to exposure to harmful plasma radicals, preventing damage before it occurs.
2Object-affected harmful factors
If pores are filled with liquid compound, then protection against plasma damage is improved, but etching efficiency decreases
Solution Approach 1:
The liquid compound selectively fills only the pore structures while leaving the surface regions accessible for etching. This local application ensures that protection is provided exactly where needed (in the pores) without interfering with the etching process on the surface.
Solution Approach 2:
The liquid compound is applied in sufficient quantity to fill the pores but not so much as to coat the surface excessively. This partial filling approach provides adequate protection while maintaining etching efficiency by avoiding surface obstruction.
3Object-affected harmful factors
If conventional sealing methods are used, then pore protection is improved, but cleaning difficulty increases
Solution Approach 1:
The liquid compound is selected with specific physical parameters (vapor pressure, boiling point) that allow it to be easily removed by heating. By controlling these parameters, the compound provides effective protection during etching while enabling simple thermal decomposition for cleaning, avoiding the need for complex cleaning procedures.
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 method effectively protects porous materials from excessive damage during plasma etching, facilitates easier cleaning, and allows for precise control of the etching process, reducing material degradation and maintaining the porosity of low-k dielectrics, thus enhancing the reliability and efficiency of semiconductor device fabrication.
Implementation Method 1
contacting a porous material with an organic gas in an environment having a pressure Pi and a temperature T1, wherein said organic gas is such that at said pressure Pi and at said temperature T1 it remains a gas when outside of said porous material but condenses as an organic liquid when in contact with said porous material, thereby filling pores of said porous material with said organic liquid
Implementation Method 2
Plasma etching treatment of said porous material having pores filled with said organic liquid, thereby evaporating a fraction of said organic liquid filling the pores of said porous material
Data Source
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AI summary
Method for etching a porous material (3) in an environment, said method comprising the successive steps of I. contacting a porous material (3) with an organic gas (11g) in an environment having a pressure P1 and a temperature T1, wherein said organic gas (11g) is such that at said pressure P1 and at said temperature T1 it remains a gas when outside of said porous material (3) but condenses as an organic liquid (11l) when in contact with said porous material (3), thereby filling pores (12) of said porous material (3) with said organic liquid (11l); II. plasma etching treatment of said porous material (3) having filled pores (12), thereby evaporating a fraction of said organic liquid (11l) filling the pores of said porous material (3), said successive steps being repeated n times with n with n ≥ 1.