Invertible Cylindrical Target Structure for Longer Sputtering Life
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Solution Overview
Problem
The frequent replacement of target members in film forming apparatuses leads to increased running costs due to exposure of bonding materials and support members to plasma ions, resulting in impurities being introduced into the film formation process.
Innovation Solution
A cylindrical target with a symmetrical structure is used, allowing for inversion to extend the life of the target member by rearranging the less consumed portion to the high plasma density area, and a sealing mechanism with multiple O-rings is employed to maintain efficient cooling and prevent leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the target member is fixed to the support member via bonding material, then the target member can be securely held in place, but the target member is consumed and the bonding material and support member are exposed to plasma ions, resulting in impurities being introduced into the film
Solution Approach 1:
The support member wall portion is divided into three distinct portions (first, second, and third portions) with different thicknesses, creating segmented regions that serve different functions. The first and third portions have first thickness for sealing, while the second portion has greater second thickness for protection, allowing the structure to simultaneously achieve secure bonding and impurity prevention through its segmented architecture.
Solution Approach 2:
Different portions of the wall are given different thicknesses to provide locally optimized properties. The second portion has increased thickness specifically at the region most exposed to plasma ions, providing enhanced protection where needed, while maintaining adequate bonding strength in other regions through the first and third portions.
2Manufacturing precision
If the target member is replaced frequently to prevent impurity introduction, then film quality is maintained, but the running cost of the film forming apparatus increases
Solution Approach 1:
The support member is pre-designed with a three-portion thickness structure before the target member is attached. This preliminary structural preparation ensures that when the target member is in use, the plasma ions are already blocked by the thicker second portion, preventing impurity introduction and eliminating the need for frequent target replacements to maintain film quality.
Solution Approach 2:
The increased thickness of the second portion acts as a protective cushion against plasma ion exposure before the target member is consumed. This beforehand protection prevents the bonding material and support member from being exposed to ions, thereby maintaining film quality over extended periods and reducing replacement frequency.
3Ease of manufacture
If the wall portion is made uniformly thick, then manufacturing is simplified, but the target member cannot be inverted for reuse, reducing its service life
Solution Approach 1:
The wall portion is designed with asymmetric thickness distribution, creating three distinct portions with different thicknesses. This asymmetric structure enables the target member to be inverted and reused, as the varying thickness profile allows proper orientation and sealing when flipped, thereby extending the service life of the target member beyond a single use.
Solution Approach 2:
The target member is designed to be invertible by providing a symmetric three-portion thickness structure where the first and third portions are identical. This allows the target member to be flipped and reused in the opposite orientation, effectively doubling its service life while maintaining sealing integrity through the repeated first/third portion structure.
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 extends the life of the target member, reducing the frequency of replacements and subsequently lowering the running costs of the film forming apparatus while maintaining film quality.
Implementation Method 1
a film is formed on a film formation object by adhering, to the film formation object, target particles ejected from a target member by making ions contained in the plasma generated by using the electron cyclotron resonance (ECR) phenomenon collide with the target member
Implementation Method 2
the plasma generated by using the electron cyclotron resonance (ECR) phenomenon
Implementation Method 3
the target member is fixed to a support member via a bonding material
Data Source
AI summary
An object is to extend the life of the target member. The target (TA2) is designed to have a symmetrical structure so as to realize an invertible configuration. According to this, even if the consumption of the target member (71) is large on the side closer to the plasma generation unit where the plasma density is high, the portion of the target member (71) which has been located on the side closer to the film formation object where the plasma density is low and is thus consumed less can be rearranged on the side closer to the plasma generation unit where the plasma density is high, by inverting the target (TA2).