1. Field of the Invention
The present invention is related to a deposition apparatus and deposition method using the same, in particular, to a deposition apparatus having a function of bombarding surface of a work piece by ions, and a deposition method using the deposition apparatus.
2. Description of the Prior Art
Thin film deposition is an important process used in semiconductor manufacturing. For example, thin film deposition may be used to deposit various materials, such as monocrystalline, polycrystalline, amorphous and epitaxial material, on work piece (e.g., semiconductor substrate) to form thin film. In conventional thin film deposition process, the adjustable process parameters include nothing else but vacuum degree, temperature of the process chamber or concentration of the deposition material; however, there is a limitation of the conventional to control the result of the film deposition.
In view of the problem as above, it is now a current goal to control the result of the film deposition, effectively.
The present invention provides a deposition apparatus and a deposition method using the same. The deposition apparatus may provide an extra ion source to bombard the work piece by ions, so as to accelerate the thin film deposition and increase the controlled parameter of the thin film deposition process.
One of the embodiments of the present invention is a deposition apparatus, comprising: a process chamber, wherein a work piece is disposed therein; a plasma source chamber coupled to the process chamber, the plasma source chamber comprising a first plasma generator for ionizing a first gas in the plasma source chamber to generate a first plasma having ions, the ions of the first plasma bombard the work piece; and a second plasma generator disposed within the process chamber, the second plasma generator ionized a second gas in the process chamber to generate a second plasma having radical to deposit a surface of the work piece.
The other embodiment of the present invention is a deposition method, comprising the following steps: positioning a work piece in a process chamber, wherein the process chamber comprise a second plasma generator; operating a first plasma generator in a plasma source chamber to ionize a first gas in the plasma source chamber and then generate a first plasma having ions, the ions of the first plasma bombard the work piece, wherein the plasma source chamber coupled to the process chamber; and operating the second plasma generator to ionize a second gas in the process chamber, and then generate a second plasma having radical, the second plasma having radical deposits a surface of the work piece.
The purpose, technical content, characteristic and effect of the present invention will be easy to understand by reference to the following detailed descriptions, when taken in conjunction with the accompanying drawings and the particular embodiment.
The embodiments as above only illustrate the technical concepts and characteristics of the present invention; it is purposed for person ordinary skill in the art to understand and implement the present invention, but not for the limitation to claims of the present invention. That is, any equivalent change or modification in accordance with the spirit of the present invention should be covered by the appended claims.
In this example, plasma source chamber 202 is coupled to gas inlet 260 to supply the first gas 261 into plasma source chamber 202. Power source 246 is coupled to one or more first plasma generator 230 through an impedance matching network (not shown) to introduce LF, RF, or VHF power into plasma source chamber 202 via the one or more first plasma generator 230. The introduced LF, RF, or VHF power energizes electrons in plasma generation region 232, which in turn ionize and dissociate the first gas 261, thereby forming first plasma 220 in plasma generation region 232. First plasma generator 230 is disposed within plasma source chamber 202 and is configured to enable plasma 220 to be stably generated and sustained at pressures below 0.1 Pa without the use of an additive gas (e.g., hydrogen, argon, etc.).
In one embodiment, the first gas 261 may comprise atoms to be deposited on the surface of the work piece, for example, the first gas may comprise: AsH3, PH3, SiH4, SiH2(CL)2, Si2H6, SiF4, GeH4, CH3OH,O2, N2O, B2H6, Ar, Kr, Xe or NH3. In the other embodiment, the first gas 261 may comprise atoms to be implanted on the surface of the work piece, for example, the first gas may comprise: AsH3, PH3, BF3, H2, N2, O2, He, Ar, Kr, Xe, N2, CO2, CO, CF4 or CH4.
The reaction in the plasma source chamber will be described. When the first gas accesses into the plasma source chamber, a first reaction, that is, dissociative ionization and electron impact ionization will be conducted. For example, in the case of the first gas is AsH3, the first reaction are conducted as follows:
Dissociative Ionization
e+AsH3→AsH2++H*+2e
e+AsH3→AsH++H2+e
e+AsH3→As+H2+H*+2e
e+AsH3→AsH3++2e
As the result, the first gas is ionized and dissociated by the first plasma generator and generate excited electron, that is, the first plasma having ions. The ion beams of the first plasma will be extracted and accelerated toward the work piece in the process chamber by the grid to conduct implantation or to assist deposition.
Although in this example, plasma source chamber 202 is configured to supply LF, RF or VHF power through first plasma generator 230 to form first plasma 220, it should be recognized that other configurations may be possible to supply power into plasma source chamber 202. For example, first plasma generator 230 may comprise antennas or induction coils that are disposed in or around the outside of plasma source chamber 202. In another example, plasma source chamber 202 may be configured to supply UHF or microwave power into plasma source chamber 202 to form first plasma 220. In yet another example, plasma source chamber 202 may be configured to generate energetic thermionic electrons in plasma generation region 232 to form plasma 220. For example, a tungsten filament may be heated in plasma generation region 232 to generate energetic thermionic electrons.
The deposition apparatus 200 also comprises a second plasma generator 301 disposed in the process chamber 204 and an gas inlet 262 to access a third gas 263 into the process chamber 204. Wherein, the second plasma generator 301 may comprise antennas or induction coils that are disposed in or around the outside of process chamber 204, and the power of the second plasma generator may be different from that of the first plasma generator.
The second plasma generator 301 may ionize a second gas in the process chamber 204 to generate second plasma 330 having radical, herein, the second gas comprises ion beams 234 of the first plasma 220 and the third gas 263. Wherein, the ion beams 234 of the first plasma 220 may pass through the second plasma generator 301 and bombard the work piece 206, and the second plasma 330 having radical may deposit a surface of the work piece 206. In this case, the bombardment by the ion beams 234 on the work piece may facilitate the deposition of the second plasma, and therefore approve the deposition efficiency.
In one embodiment, the third gas 263 may comprise atoms to be deposited on the surface of the work piece, for example, the third gas may comprise: AsH3, PH3, SiH4, SiH2(CL)2, Si2H6, SiF4, GeH4, CH3OH,O2, N2O, B2H6, Ar, Kr, Xe or NH3.
The reaction in the process chamber will be described. When the second gas accesses into the process chamber, that is, when the third gas and the ions access into the process chamber through the gas inlet and grids, respectively, a secondary reaction (ion-molecule or radical-molecule reaction and recombination of the radicals and ions) will be conducted. For example, in the case of the third gas is AsH3, the secondary reaction are conducted as follows:
Ion-molecule or Radical-Molecule Reaction:
AsH3++AsH3→AsH2++AsH2*+H2
AsH2++AsH3→AsH3++AsH2*
AsH++AsH3→AsH2++AsH2*
AsH3+H*→H2+AsH2*
e+AsH3→AsH3
e+AsH2++H*→AsH3
e+AsH+2H*→AsH3
e+As+→As
e+As++3H*→AsH3
H*+AsH2→AsH3
H2+AsH*→AsH3
As the result, most of radicals (AsH2*) are form by second plasma generator in the process chamber, and the radicals may react with the ions and hydrogen to deposit on the surface of the work piece.
Process chamber 204 may be coupled, via throttle valve 238, to high-speed vacuum pump 240. For example, high-speed vacuum pump 240 may be configured to pump at a rate of at least several hundred liters per second. Throttle valve 238 and high-speed vacuum pump 240 may be configured to maintain an operating pressure of below 0.1 Pa (and in some cases below 0.02 Pa) in plasma source chamber 202 and process chamber 204. Additionally, the deposition apparatus may include one or more cryo-panels disposed within process chamber. The one or more cryo-panels may serve to capture residual gases or organic vapors to achieve ultra-low operating pressures. In one example, the one or more cryo-panels may be configured to maintaining a pressure of below 0.02 Pa in plasma source chamber 202 and process chamber 204.
The deposition apparatus 200 in the present invention further comprises a plurality of grids 224 disposed between the first plasma generator 230 and a support structure 208 disposed with the process chamber 204. One or more grids of grids 224 may be coupled to one or more bias power sources 248 to apply a bias voltage to grids 224. Bias power source 248 may be, for example, a DC power source, a pulsed DC power source, an RF power source, or a combination thereof. In this example, grids 224 are configured to extract ion beam 234 from first plasma 220 and accelerate ion beam 234 to a desired energy level towards work piece 206.
Additionally, grids 224 may be configured to focus ion beam 234 and thus collimate ion beam 234. It should be recognized that grids 224 may be configured to extract multiple ion beamlets from plasma 220 and that ion beam 234 may thus comprise multiple ion beamlets. Furthermore, grids 224 may control the ion concentration distribution of the ion beam 234 of the first plasma 220.
As shown in
The support structure 208 disposed with the process chamber 204 is configured to position work piece 206 in the path of ion beam 234 for ions bombard and second plasma 330 for deposition. Work piece 206 may be a semiconductor substrate (e.g., silicon wafer) used in fabricating IC chips or solar cells. In other cases, work piece 206 may be a glass substrate with thin-film semiconductor layers used in fabricating flat panel displays or thin-film solar cells.
In some embodiments, support structure 208 may be configured to rotate or tilt work piece 206 to control the incidence angle of ion beam 234 with respect to the perpendicular of work piece 206. It should be recognized that support structure 208 may be configured to rotate work piece 206 while tilting work piece 206 at a given angle.
In one embodiment of the present invention, the deposition apparatus may not include grids 224. In such case, support structure 208 may be configured to apply a bias voltage on work piece 206. For example, support structure may be coupled to bias power source 254 to apply a bias voltage to work piece 206. Biasing work piece 206 functions to accelerate ions from first plasma 220 towards work piece 206, thereby bombarding work piece 206 with ions.
In one embodiment of the present invention, plasma source chamber 202 includes end wall 216 disposed at one end 217 of plasma source chamber 202 and at least one sidewall 218 defining the interior of plasma source chamber 202 between end wall 216 and opposite end 222 of plasma source chamber 202. In this example, sidewall 218 is cylindrical and has a circular cross-section. However, in other cases, sidewall 218 may have a rectangular cross-section.
As shown in
Plasma source chamber 202 includes first set of magnets 210 disposed on end wall 216, second set of magnets 212 disposed on sidewall 218, and third set of magnets 214 extending across the interior of chamber 202. Each magnet of third set of magnets 214 may be housed within a protective tube. End wall 216, sidewall 218, and the third set of magnets 214 define plasma generation region 232 within the interior of plasma source chamber 202. In this example, first set of magnets 210, second set of magnets 212, and third set of magnets 214 are configured to confine energetic electrons of plasma 220 within plasma generation region 232. Energetic electrons may be defined as electrons having energy greater than 10 eV. Particularly, third set of magnets 214 is configured to confine a majority of electrons of plasma 220 having energy greater than 10 eV within plasma generation region 232 while allowing ions from plasma 220 to pass through third set of magnets 214 into process chamber 204 for ion bombard of work piece 206.
In the present of first set of magnets 210, second set of magnets 212, and third set of magnets 214, plasma 220 may become stable or sustainable at pressures below 0.1 Pa. Furthermore, the first set of magnets 210 and second set of magnets 212 may comprise ceramic permanent magnets (e.g., ferrite magnets) and are configured such that the magnetic field strength at the inner surfaces of end wall 216 and sidewall 218 is between 0.1 kG and 1 kG.
As shown in
Referring to
The magnets surround the plasma generation region may confine the energetic electrons of the plasma with the plasma generation; furthermore, the magnets may approve the deposition efficiency.
In summary, the deposition of the present invention comprises plasma source chamber and process chamber having first plasma generator and second plasma generator, respectively. Wherein the first plasma generator in the plasma source chamber may generate first plasma with ions and the ions of the first plasma will be extracted and accelerated toward the work piece in the process chamber by the grid to conduct implantation or to assist deposition. In addition, the second plasma generator may generate second plasma with radical using the accessed gas and the ions from plasma source chamber to conduct deposition. As described above, the deposition apparatus of the present invention may conduct different process modes (for example, implantation and deposition) by operate plasma source chamber and process chamber respectively or simultaneously; furthermore, the deposition apparatus of the present invention has excellent deposition efficiency compared to the conventional deposition device.
The embodiments as above only illustrate the technical concepts and characteristics of the present invention; it is purposed for person ordinary skill in the art to understand and implement the present invention, but not for the limitation to claims of the present invention. That is, any equivalent change or modification in accordance with the spirit of the present invention should be covered by the appended claims
This is a continuation-in-part of application Ser. No. 14/201,747, filed in Mar. 7, 2014.
Number | Date | Country | |
---|---|---|---|
Parent | 14201747 | Mar 2014 | US |
Child | 14952624 | US |