Gas distribution showerhead for inductively coupled plasma etch reactor
First Claim
1. A lower plate of a ceramic showerhead assembly useful in an inductively coupled plasma processing apparatus wherein semiconductor substrates supported on a substrate support are subjected to plasma etching, the lower plate comprising:
- a lower surface having a lower central portion and a lower outer portion;
a stepped upper surface having an upper central portion and an upper outer portion, wherein the upper central portion is thicker than the upper outer portion, wherein the upper outer portion includes an annular zone, and wherein the upper central portion is stepped up from the upper outer portion; and
a plurality of gas holes located in the annular zone and axially extending between the stepped upper surface and the lower surface;
wherein the lower surface includes a lower vacuum sealing surface located on the lower outer portion; and
wherein the upper outer portion includes inner and outer upper vacuum sealing surfaces defining the annular zone.
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Abstract
A two piece ceramic showerhead includes upper and lower plates which deliver process gas to an inductively coupled plasma processing chamber. The upper plate overlies the lower plate and includes radially extending gas passages which extend inwardly from an outer periphery of the upper plate, axially extending gas passages in fluid communication with the radially extending gas passages and an annular recess forming a plenum between the upper and lower plates. The lower plate includes axially extending gas holes in fluid communication with the plenum. The upper plate can include eight radially extending gas passages evenly spaced around the periphery of the upper plate and the lower plate can include inner and outer rows of gas holes. The two piece ceramic showerhead forms a dielectric window of the chamber through which radiofrequency energy generated by an antenna is coupled into the chamber. A gas delivery system delivers process gas to a plenum between the upper and lower plates having a gas volume of no greater than 500 cm3. The gas holes in the lower plate extend between the plenum and a plasma exposed yttria coated surface of the lower plate. The gas delivery system is operable to supply an etching gas and a deposition gas into the processing chamber such that the etching gas in the plenum can be replaced with the deposition gas within about 200 milliseconds and vice versa.
105 Citations
28 Claims
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1. A lower plate of a ceramic showerhead assembly useful in an inductively coupled plasma processing apparatus wherein semiconductor substrates supported on a substrate support are subjected to plasma etching, the lower plate comprising:
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a lower surface having a lower central portion and a lower outer portion; a stepped upper surface having an upper central portion and an upper outer portion, wherein the upper central portion is thicker than the upper outer portion, wherein the upper outer portion includes an annular zone, and wherein the upper central portion is stepped up from the upper outer portion; and a plurality of gas holes located in the annular zone and axially extending between the stepped upper surface and the lower surface; wherein the lower surface includes a lower vacuum sealing surface located on the lower outer portion; and wherein the upper outer portion includes inner and outer upper vacuum sealing surfaces defining the annular zone. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 27, 28)
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13. A lower plate of a ceramic showerhead assembly useful in an inductively coupled plasma processing apparatus wherein semiconductor substrates supported on a substrate support are subjected to plasma etching, the lower plate comprising:
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a lower surface having a lower central portion and a lower outer portion; a stepped upper surface having an upper central portion and an upper outer portion, wherein the upper central portion is thicker than the upper outer portion, wherein the upper outer portion includes an annular zone; and a plurality of gas holes located in the annular zone and axially extending between the stepped upper surface and the lower surface; wherein the lower surface includes a lower vacuum sealing surface located on the lower outer portion; wherein the upper outer portion includes inner and outer upper vacuum sealing surfaces defining the annular zone; wherein the lower plate is further configured to couple to an upper plate; and wherein the upper plate includes an upper surface, a lower surface, a first plurality of gas passages extending radially and inwardly from an outer periphery of the upper plate, an annular opening, an annular zone surrounding the annular opening and recessed from the lower surface, and a second plurality of gas passages extending axially from the annular zone to the first plurality of gas passages.
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15. An upper plate of a ceramic showerhead assembly useful in an inductively coupled plasma processing apparatus wherein semiconductor substrates supported on a substrate support are subjected to plasma etching, the upper plate comprising:
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an upper surface; a lower surface; a first plurality of gas passages extending radially and inwardly from an outer periphery of the upper plate; an annular opening; an annular zone surrounding the annular opening and recessed from the lower surface; and a second plurality of gas passages extending axially from the annular zone to the first plurality of gas passages, wherein the upper plate is configured to couple to a central portion of a lower plate via the annular opening and overlie an upper surface of the lower plate such that the second plurality of gas passages are in fluid communication with a third plurality of gas holes in the lower plate when the upper plate is coupled to the lower plate. - View Dependent Claims (16, 17, 18, 19, 21, 22, 23, 24)
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20. An upper plate of a ceramic showerhead assembly useful in an inductively coupled plasma processing apparatus wherein semiconductor substrates supported on a substrate support are subjected to plasma etching, the upper plate comprising:
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an upper surface; a lower surface; a first plurality of gas passages extending radially and inwardly from an outer periphery of the upper plate; an annular opening; an annular zone surrounding the annular opening and recessed from the lower surface; a second plurality of gas passages extending axially from the annular zone to the first plurality of gas passages; and inner and outer O-ring grooves surrounding the annular zone.
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25. An upper plate of a ceramic showerhead assembly useful in an inductively coupled plasma processing apparatus wherein semiconductor substrates supported on a substrate support are subjected to plasma etching, the upper plate comprising:
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an upper surface; a lower surface; a first plurality of gas passages extending radially and inwardly from an outer periphery of the upper plate; an annular opening; an annular zone surrounding the annular opening and recessed from the lower surface; a second plurality of gas passages extending axially from the annular zone to the first plurality of gas passages; and 16 first mounting holes extending axially from the upper surface to the lower surface, the first mounting holes located about 0.5 inch from the outer periphery. - View Dependent Claims (26)
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Specification