Active Energy Assist Baking for Ultra-Low k Dielectric Moisture Removal
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Solution Overview
Problem
Low-k and ultra-low k dielectric materials used in semiconductor manufacturing are prone to moisture absorption and plasma damage, leading to electrical performance and reliability issues, and existing methods for removing moisture and by-products are inefficient, affecting interconnect formation.
Innovation Solution
Active Energy Assist (AEA) baking, which involves exposing the substrate to light with wavelengths greater than 400 nm and concurrent thermal heating, is used to remove moisture and repair damage without increasing the dielectric constant, improving the efficiency of interconnect formation processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional thermal baking is used to remove moisture from ultra-low k dielectric layers, then moisture removal is achieved, but the thermal budget is excessive and process time is prolonged
Solution Approach 1:
The patent replaces conventional thermal baking (purely thermal energy) with active energy assist baking that uses photons (electromagnetic radiation) to assist the baking process. The light source emits photons at specific wavelengths that are absorbed by moisture and organic compounds in the dielectric layer, providing direct energy to break molecular bonds and evaporate moisture more efficiently than thermal energy alone, thereby reducing process time while maintaining moisture removal effectiveness.
Solution Approach 2:
The patent changes the energy parameter by introducing light with specific wavelength ranges (UV to near-infrared) to the baking process. By controlling the spectral distribution of the light source and the temperature profile, the process achieves faster moisture removal compared to conventional thermal baking, effectively changing the energy delivery mechanism to improve process efficiency.
2Reliability
If conventional thermal baking is used to remove moisture and by-products, then moisture removal is achieved, but thermal budget is excessive affecting subsequent processing
Solution Approach 1:
The patent substitutes a portion of the thermal energy with electromagnetic radiation energy. The light source provides direct photon energy that is absorbed by moisture and organic by-products, enabling their removal without requiring proportionally high thermal energy input. This substitution reduces the overall thermal budget while achieving the same or better dielectric layer quality.
Solution Approach 2:
The patent utilizes phase transitions of moisture and organic compounds from liquid/solid to vapor phase through direct photon absorption. The light energy directly facilitates the phase change process, allowing moisture and by-products to be removed as vapor without requiring the same level of thermal energy that would be needed for conventional thermal evaporation, thus reducing thermal budget.
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
AEA baking reduces moisture absorption, conserves thermal budget, and improves process time, reducing costs and increasing tool utilization while maintaining the low dielectric constant of the materials.
Implementation Method 1
exposed to light having only wavelengths greater than 400 nm for about 1 to about 20 minutes at a temperature of about 300 to about 400 degrees Celsius
Implementation Method 2
heated and exposed to light having only wavelengths greater than 400 nm for about 1 to about 20 minutes at a temperature of about 300 to about 400 degrees Celsius
Data Source
AI summary
An Active Energy Assist (AEA) baking chamber includes an AEA light source assembly and a heater pedestal. The AEA baking chamber further includes a controller for controlling a power input to the AEA light source assembly and a power input to the heater pedestal. A method of forming interconnects on a substrate includes etching a substrate and wet cleaning the etched substrate. The method further includes active energy assist (AEA) baking the substrate after the wet-cleaning. The AEA baking includes placing the substrate on a heater pedestal in an AEA chamber, exposing the substrate to light having a wavelength equal to or greater than 400 nm, wherein said light is emitted by a light source and controlling the light source and the heater pedestal using a controller.