Plasma CVD Showerhead Rectifying Plate Surface Roughness
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Solution Overview
Problem
The remote plasma cleaning method for semiconductor CVD apparatuses faces issues with ion bombardment damage to electrodes and subsequent contamination, leading to increased maintenance costs and productivity losses due to inactivation of cleaning gas at the blocker plate, which is exacerbated by the porous surface structure of conventional alumina ceramics.
Innovation Solution
A plasma CVD apparatus with a gas-introducing system featuring a showerhead, a rectifying plate made of high-purity sapphire or alumina ceramics with controlled surface roughness, and a piping unit that separates the active species from the rectifying plate, preventing inactivation and maintaining high cleaning speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If remote plasma cleaning method is used to avoid ion bombardment damage to electrodes, then electrode lifespan is improved, but cleaning gas is inactivated at the blocker plate causing cleaning speed to decrease
Solution Approach 1:
The invention changes the surface roughness parameter of the blocker plate from conventional porous alumina ceramics to a controlled smooth surface (Ra≤0.4μm). This parameter change prevents active species inactivation while maintaining the remote plasma cleaning configuration, thus preserving both electrode lifespan and cleaning speed.
Solution Approach 2:
The invention applies different surface quality requirements to different regions: the blocker plate surface is made smooth to prevent inactivation, while other components can maintain conventional properties. This localized quality adjustment solves the contradiction by targeting the specific interface where gas activation occurs.
2Ease of manufacture
If conventional alumina ceramics with porous surface structure is used for blocker plate, then manufacturing is easier, but active species are inactivated leading to reduced cleaning efficiency
Solution Approach 1:
The invention changes the surface roughness parameter from porous (conventional) to smooth (Ra≤0.4μm). This parameter change reduces cleaning efficiency initially but prevents active species inactivation, thereby maintaining high cleaning efficiency over extended operation periods.
Solution Approach 2:
The invention treats the blocker plate as a consumable component with controlled surface properties. By using a smooth surface that prevents inactivation, the blocker plate maintains effectiveness throughout its service life, reducing replacement frequency and maintaining productivity.
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 solution effectively prevents ion bombardments and maintains high cleaning speed over a long period, ensuring uniform film deposition and reducing maintenance time and costs, thereby enhancing productivity.
Implementation Method 1
NF3 is introduced to an isolated second plasma discharge chamber at a controlled flow rate, and then dissociated and activated by the 2.45 GHz microwaves supplied to the plasma discharge chamber via a waveguide from a microwave oscillator, to generate fluorine radicals
Implementation Method 2
the 2.45 GHz microwaves supplied to the plasma discharge chamber via a waveguide from a microwave oscillator
Implementation Method 3
Generated fluorine radicals are introduced via a conduit pipe into the reactor where film is deposited, to gasify and thereby remove the attachments on the interior walls of the reactor
Implementation Method 4
film deposition gas is supplied uniformly over the entire wafer surface from a showerhead so that film is deposited uniformly over the entire wafer
Implementation Method 5
a rectifying plate installed in the interior space of the showerhead, dividing the interior space into an upper space and a lower space, and having multiple holes through which the upper space and the lower space are communicated
Data Source
AI summary
A gas-introducing system for plasma CVD and cleaning includes: a showerhead including a top plate with a gas inlet port and a shower plate; a rectifying plate installed in the interior space of the showerhead and dividing the interior space into an upper space and a lower space; a structure for inhibiting inactivation of active species of the activated cleaning gas at the rectifying plate; and a piping unit for connecting the gas inlet port of the showerhead to a remote plasma unit and a reaction gas introduction port.