A substrate processing apparatus according to an embodiment of the present invention will be now described with reference to the drawings.
In the following description, a substrate refers to a semiconductor wafer, a glass substrate for a liquid crystal display, a glass substrate for a PDP (Plasma Display Panel), a glass substrate for a photo mask, a glass substrate for an optical disk, and the like.
(1) Configuration of Substrate Processing Apparatus
The configuration of the substrate processing apparatus according to the present embodiment will be described while referring to the drawing.
In the substrate processing apparatus, processing for etching a film on a substrate, processing for cleaning a surface of the substrate, processing for removing a polymer residue (e.g., a resist residue) on the substrate, and so on are performed. Processing for etching an oxide film on the substrate will be described by way of example below.
As shown in
The spin chuck 21 is secured to an upper end of a rotating shaft 25 that is rotated by a chuck rotation mechanism 36. The substrate W is rotated in a state where it is horizontally held by the spin chuck 21 when etching processing using a processing liquid is performed.
A first motor 60 is provided outside the spin chuck 21. A first rotating shaft 61 is connected to the first motor 60. A first arm 62 is connected to the first rotating shaft 61 so as to extend in the horizontal direction, and its tip is provided with a processing liquid nozzle 50.
The processing liquid nozzle 50 supplies a processing liquid for etching an oxide film formed on the substrate W onto the substrate W. The details of the processing liquid supplied onto the substrate W by the processing liquid nozzle 50 will be described later.
A second motor 71 is provided outside the spin chuck 21. A second rotating shaft 72 is connected to the second motor 71. A second arm 73 is connected to the second rotating shaft 72. A pure water nozzle 70 is provided at a tip of the second arm 73. The pure water nozzle 70 supplies pure water onto the substrate W in rinsing processing after the etching processing. When the etching processing is performed using the processing liquid nozzle 50, the pure water nozzle 70 is retracted to a predetermined position.
The rotating shaft 25 to which the spin chuck 21 is fixed is composed of a hollow shaft. A processing liquid supply pipe 26 is inserted through the rotating shaft 25. A processing liquid such as pure water or a chemical liquid serving as an etchant is supplied to the processing liquid supply pipe 26. The processing liquid supply pipe 26 extends to a position in close proximity to a lower surface of the substrate W held in the spin chuck 21. A lower surface nozzle 27 for discharging the processing liquid toward the center on the lower surface of the substrate W is provided at a tip of the processing liquid supply pipe 26.
The spin chuck 21 is accommodated within a processing cup 23. A cylindrical partition wall 33 is provided inside the processing cup 23. A drain space 31 for draining the processing liquid used for the etching processing of the substrate W is formed so as to surround the spin chuck 21. Furthermore, a liquid recovery space 32 for recovering the processing liquid used for the etching processing of the substrate W is formed between the processing cup 23 and the partition wall 33 so as to surround the drain space 31.
A drain pipe 34 for introducing the processing liquid into a drain processing device (not shown) is connected to the drain space 31. A recovery pipe 35 for introducing the processing liquid into a recovery and reuse device, described later, is connected to the liquid recovery space 32.
A guard 23 is provided above the processing cup 24 for preventing the processing liquid from the substrate W from being splashed outward. The guard 24 is shaped to be rotationally-symmetric with respect to the rotating shaft 25. An annular-shaped drain guide groove 41 with a V-shaped cross section is formed inwardly at an upper end of the guard 24.
A liquid recovery guide 42 having an inclined surface that is inclined outwardly downward is formed inwardly at a lower end of the guard 24. A partition wall housing groove 43 for receiving the partition wall 33 inside the processing cup 23 is formed in the vicinity of an upper end of the liquid recovery guide 43. A guard lifting mechanism (not shown) composed of a ball-screw mechanism or the like is connected to the guard 24.
The guard lifting mechanism moves the guard 24 upward and downward between a recovery position in which the liquid recovery guide 42 is opposite to outer edges of the substrate W held on the spin chuck 21 and a drain position in which the drain guide groove 41 is opposite to the outer edges of the substrate W held on the spin chuck 21.
When the guard 24 is in the recovery position (the position of the guard 24 shown in
Above the spin chuck 21, a disk-shaped shielding plate 22 having an opening at its center is provided. A supporting shaft 29 extends vertically downward from the vicinity of an end of an arm 28, and the shielding plate 22 is mounted on a lower end of the supporting shaft 29 so as to be opposite to the upper surface of the substrate W held on the spin chuck 21.
A nitrogen gas supply passage 30 that communicates with the opening of the shielding plate 22 is inserted through the supporting shaft 29. Nitrogen gas (N2) is supplied to the nitrogen gas supply passage 30. The nitrogen gas supply passage 30 supplies the nitrogen gas to the substrate W at the time of drying processing after the rinsing processing with pure water.
A pure water supply pipe 39 that communicates with the opening of the shielding plate 22 is inserted through the nitrogen gas supply passage 30. Pure water or the like is supplied to the pure water supply pipe 39.
A shielding plate lifting mechanism 37 and a shielding plate rotation mechanism 38 are connected to the arm 28. The shielding plate lifting mechanism 37 moves the shielding plate 22 upward and downward between a position in close proximity to the upper surface of the substrate W held on the spin chuck 21 and a position spaced upwardly apart from the spin chuck 21. The shielding plate rotation mechanism 38 rotates the shielding plate 22.
(2) Configuration of Recovery and Reuse Device
The configuration of a recovery and reuse device for reusing the processing liquid recovered through the recovery pipe 35 shown in
As shown in
The recovery tank 110 is connected to a purification tank 112 by a pipe 111. A pump 113, an impurity removal filter 114, and an ion component removal filter 115 are inserted in this order through the pipe 111 in a direction away from the recovery tank 110.
In the present embodiment, in order to etch an oxide film formed on the substrate W, used as the processing liquid supplied to the substrate W by the processing liquid nozzle 50 shown in
The fluorine-based organic solvent is mixed with the acid liquid to improve the precision of the etching processing. However, the fluorine-based organic solvent is not easily mixed with the acid liquid because it is hydrophobic.
Therefore, in the present embodiment, the hydrophilic organic solvent is mixed with the acid liquid and the fluorine-based organic solvent. Thus, the fluorine-based organic solvent is satisfactorily mixed with the acid liquid.
Examples of the fluorine-based organic solvent include hydrofluoroethers (HFEs), hydrofluorocarbons (HFCs), and per-fluoroalkylhaloeters (PFAHEs).
Specific examples of the hydrofluoroethers include CH3OCF2CF3, C2H5OCF2CF3, C2F5C (OCH3) CF (CF3)2, n-C3F7OCH3, (CF3)2CFOCH3, n-C4F9OCH3, (CF3)2CFCF2OCH3, n-C3F7OC2H5, n-C4F9OC2H5, (CF3)3COCH3, (CF3)3COC2H5, C4F9OC2F4H, C6F13OCF2H, HCH3F6OC3F6H, C3F7OCH2F, HCF2OCF2OCF2H, HC2OCF2CF2OCF2H, HC3F6OCH3, and HCF2OCF2OC2F4OCF2H.
Specific examples of the hydrofluorocarbons include CF3CHFCHFCF2CF3, CF3CH2CF2H, CF2HCF2CH2F, CH2FCF2CFH2, CF2HCH2CF2H, CF2HCFHCF2H, CF3CFHCF3, CF3CH2CF3, CHF2 (CF2) H, CF3CF2CH2CH2F, CF3CH2CF3CH2F, CH3CHFCF2CF3, CF3CH2CH2CF3, CH2FCF2CF2CH2F, CF3CH2CF2CH3, CHF2CH(CF3)CF3, CHF(CF3)CF2CF3, CF3CH2CHFCF2CF3, CF3CHFCH2CF2CF3, CF3CH2CHFCF2CF3, CF3CHFCH2CF2CF3, CF3CH2CF2CH2CF3, CF3CHFCHFCF2CF3, CF3CH2CH2CF2CF3, CH3CHFCF2CF2CF3, CF3CF2CF2CH2CH3, CH3CF2CF2CF2CF3, CF3CH2CHFCH2CF3, CH2FCF2CF2CF2CF3, CHF2CF2CF2CF2CF3, CH3CF(CHFCHF2)CF3, CH3CH (CF2CF3)CF3, CHF2CH(CHF2)CF2CF3, CHF2CF(CHF2)CF2CF3, CHF2CF2CF(CHF2)CF2CF3, CHF2CF(CHF2)CF2CF3, CHF2CF2CF(CF3)2, CHF2(CF2)4CF2H, (CF3CH2)2CHCF3, CH3CHFCF2CHFCHFCF3, HCF2CHFCF2CF2CHFCF2H, H2CFCF2CF2CF2CF2CF2H, CHF2CF2CF2CF2CF2CHF2, CH3CF(CF2H)CHFCHFCF3, CH3CF(CF3)CHFCHFCF3, CH3CF(CF3)CF2CF2CF3, CHF2CF2CH(CF3)CF2CF3, CHF2CF2CF(CF3)CF2CF3, CH3CHFCH2CF2CHFCF2CF3, CH3(CF2)5CH3, CH3CH2(CF2)CF4CF3, CF3CH2CH2(CF2)3CF3, CH2FCF2CHF(CF2)3CF3, CF3CF2CF2CHFCHFCF2CF3, CF3CF2CF2CHFCFCHFCF2CF3, CF3CF2CF2CHFCF2CF2CF3, CH3CH(CF3)CF2CF2CF2CH3, CH3CF(CF3)CH2CFHCF2CF3, CH3CF(CF2CF3)CHFCF2CF3, CH3CH2CH(CF3)CF2CF2CF3, CHF2CF(CF3)(CF2)3CH2F, CH3CF2C(CF3)2CF2CH3, CHF2CF(CF3)(CF2)3CF3, CH3CH2CH2CH2CF2CF2CF2CF2CF3, CH3 (CF2)6CH3, CHF2CF(CF3)(CF2)4CHF2, CHF2CF(CF3)(CF2)4CHF2, CH3CH2CH(CF3)CF2CF2CF2CF3, CH3CF(CF2CF3)CHFCF2CF2CF3, CH3CH2CH2CHFC(CF3)2CF3, CH3C(CF3)2CF2CF2CF2CH3, CH3CH2CH2CF(CF3)CF(CF3)2, and CH2FCF2CF2CHF(CF2)3CF3.
Furthermore, specific examples of the per-fluoroalkylhaloeters include c-C6F11-OCH2Cl, (CF3)2CFOCHCl2, (CF3)2CFOCH2Cl, CF3CF2CF2OCH2Cl, CF3CF2CF2OCHCl2, (CF3)2CFCF2OCHCl2, (CF3)2CFCF2OCH2Cl, CF3CF2CF2CF2OCH2Cl, (CF3)2CFCF2OHClCH3, CF3CF2CF2CF2OCHClCH3, (CF3)2CFCF(C2F5) OCH2Cl, (CF3)2CFCF2OCH2Br, and CF3CF2CF2OCH2I. In the present embodiment, used as the fluorine-based organic solvent are hydrofluoroethers (hereinafter simply referred to as HFEs).
The HFEs have a boiling point lower than those of pure water and IPA (isopropyl alcohol) generally used for cleaning processing, have a specific gravity (density) higher than that of IPA, and have surface tension lower than that of IPA. The solubility of the HFEs in pure water is higher than that of IPA.
Examples of the hydrophilic organic solvent include alcohols and ketones (e.g., acetone).
The processing liquid stored in the recovery tank 110 is stored in the purification tank 112 after passing through the impurity removal filter 114 and the ion component removal filter 115 via the pipe 111 by a suction operation of the pump 113. In the impurity removal filter 114, impurities (e.g., water, an etching residue, particles, or the like) included in the processing liquid are removed.
In the ion component removal filter 115, an ion component (mainly anions) in the processing liquid including an acid liquid, HFEs, and a hydrophilic organic solvent is removed.
In the present embodiment, the ion component removal filter 115 removes fluorine ions (F−) when hydrofluoric acid (HF) is used as the acid liquid, while removing chlorine ions (Cl−) when hydrochloric acid (HCl) is used as the acid liquid.
Similarly, the ion component removal filter 115 removes sulfate ions (SO42−) when sulfuric acid (H2SO4) is used as the acid liquid, while removing phosphate ions (PO43−) when phosphoric acid (H3PO4) is used as the acid liquid.
In this case, hydrogen ions (H+) are released as hydrogen molecules (H2). Thus, the acid liquid is removed from the processing liquid.
The ion component removal filter 115 also removes water, a hydrophilic organic solvent, metal ions, or the like included in the processing liquid.
In such a way, the acid liquid, the hydrophilic organic solvent, and the impurities are removed from the processing liquid.
Here, in the present embodiment, a filter composed of alumina, for example, can be employed as the ion component removal filter 115. Alumina is white crystal powder obtained by burning aluminum hydroxide Alumina (α-alumina) obtained by burning aluminum hydroxide at a high temperature is chemically stable, has a high melting point, and has high mechanical strength and insulation resistance, and has high hardness. Alumina can be used as an adsorbent capable of removing the ion component included in the processing liquid because it has a hydroxyl group (—OH) and has a pore distribution like activated carbon. The ion component removal filter 115 in this example is a container packed with granular sintered alumina spheres obtained by sintering the crystal powder.
Then, the processing liquid from which the ion component has been removed by the ion component removal filter 115 is stored within the purification tank 112 through the pipe 111. The processing liquid from which the ion component has been removed by the ion component removal filter 115 is hereinafter referred to as a post-removal processing liquid.
Provided in the purification tank 112 is a concentration sensor S1 for measuring the concentration of anions (e.g., fluorine ions (F−), chlorine ions (Cl−), sulfate ions (SO42−) or phosphate ions (PO43−) remaining in the post-removal processing liquid within the purification tank 112. Further provided in the purification tank 112 is a concentration sensor S2 for measuring the concentration of a hydrophilic organic solvent (e.g., alcohols or ketones) remaining in the post-removal processing liquid within the purification tank 112.
The purification tank 112 is connected to one liquid inlet of a mixing valve 117 by the pipe 116. A pump 118 is inserted through the pipe 116. By such a configuration, the post-removal processing liquid stored within the purification tank 112 is fed into the mixing valve 117 through the pipe 116 by a suction operation of the pump 118.
An acid liquid supply source 120 and a hydrophilic organic solvent supply source 123 are respectively connected to the other two liquid inlets of the mixing valve 117 through a pipe 119 and a pipe 122. A valve 121 is inserted through the pipe 119, and a valve 124 is inserted through the pipe 122.
The acid liquid supply source 120 supplies an acid liquid (hydrofluoric acid (HF), hydrochloric acid (HCl), sulfuric acid (H2SO4), phosphoric acid (H3PO4), or the like), and the hydrophilic organic solvent supply source 123 supplies a hydrophilic organic solvent (alcohols or ketones).
In such a configuration, the acid liquid from the acid liquid supply source 120 is supplied to the mixing valve 117 through the pipe 119 and the valve 121 depending on the results of the measurement made by the concentration sensor S1. In the mixing valve 117, the post-removal processing liquid and the supplied acid liquid are mixed with each other.
The hydrophilic organic solvent from the hydrophilic organic solvent supply source 123 is supplied to the mixing valve 117 through the pipe 122 and the valve 124 depending on the results of the measurement made by the concentration sensor S2. In the mixing valve 117, the post-removal processing liquid and the supplied hydrophilic organic solvent are mixed with each other.
A liquid outlet of the mixing valve 117 is connected to the processing liquid nozzle 50 shown in
Here, one end of a pipe 126 is connected to the purification tank 112. The other end of the pipe 126 is connected to a portion of the pipe 111 between the pump 113 and the impurity removal filter 114. A pump 128 and a backflow preventing valve 129 are inserted through the pipe 126.
When the concentration of the anions measured by the concentration sensor S1 or the concentration of the hydrophilic organic solvent measured by the concentration sensor S2 respectively exceed predetermined threshold values, a valve 127 is opened. Thus, the post-removal processing liquid within the purification tank 112 is fed into the pipe 111 through the pipe 126 and the backflow preventing valve 129 by a suction operation of the pump 128.
The post-removal processing liquid fed into the pipe 111 is fed into the purification tank 112 after the impurity removal filter 114 and the ion component removal filter 115 remove at least one of the impurities and the ion component. The above-mentioned processing is repeated until the concentration of the anions measured by the concentration sensor S1 and the concentration of the hydrophilic organic solvent measured by the concentration sensor S2 respectively reach not more than the above-mentioned predetermined threshold values. This allows the purity of the fluorine-based organic solvent in the post-removal processing liquid to be increased.
The new processing liquid recovered and reused by the recovery and reuse device 100 may be drained outward by a pipe and a drain device (which are not shown) after processing in lots of the substrates W is terminated, for example.
(3) Control System of Substrate Processing Apparatus
In
(4) Effects of the Present Embodiment
In the present embodiment, the acid liquid can be thus removed from the processing liquid by removing the anions of the acid liquid in the processing liquid, so that the post-removal processing liquid including the fluorine-based organic solvent can be obtained. Furthermore, a processing liquid having a desired concentration and components can be reproduced by mixing the acid liquid with the post-removal processing liquid. In such a way, a high-cost fluorine-based organic solvent can be reused. This allows the processing cost to be reduced.
Since the impurity removal filter 114 removes the impurities included in the processing liquid that has already been used, the purity of the fluorine-based organic solvent included in the post-removal processing liquid can be increased. Furthermore, since the post-removal processing liquid is returned to the upstream of the impurity removal filter 114 on the basis of the results of the measurements made by the concentration sensors S1 and S2, the purity of the fluorine-based organic solvent included in the post-removal processing liquid can be further increased. This allows a new processing liquid having high purity to be produced in the mixing valve 117.
In the present embodiment, the mixing valve 117 mixes at least one of the acid liquid and the hydrophilic organic solvent in a desired amount with the fluorine-based organic solvent. Consequently, the ratio of components in the processing liquid to be supplied onto the substrate W by the processing liquid nozzle 50 can be adjusted. This allows a processing liquid corresponding to the type of film formed on the substrate W, processing conditions, and so on to be supplied.
(5) Another Embodiment
Although in the above-mentioned embodiment, the pure water nozzle 70 for supplying pure water onto the substrate W is provided, the present invention is not limited to the same. The pure water nozzle 70 need not be provided, provided that the following is carried out.
That is, valves 121 and 124 are closed so that an acid liquid and a hydrophilic organic solvent are not mixed with a fluorine-based organic solvent serving as a post-removal processing liquid in a mixing valve 117. This allows the fluorine-based organic solvent to be supplied onto a substrate W from a processing liquid nozzle 50 at the time of rinsing processing. Thus, the substrate W is cleaned using a highly volatile fluorine-based organic solvent at the time of rinsing processing, to improve drying properties as well as eliminate the necessity of providing a pure water nozzle 70. This allows space saving of a substrate processing apparatus MP.
Although in the above-mentioned embodiment, an impurity removal filter 114 and an ion component removal filter 115 are provided in a series manner in a pipe 111, the present invention is not limited to the same. For example, they may be provided in a parallel manner, and they may be respectively provided with valves. In this case, the post-removal processing liquid can be selectively returned to one or both of the impurity removal filter 114 and the ion component removal filter 115 by a pump 128. This allows impurities, an acid liquid, and a hydrophilic organic solvent to be efficiently removed.
Furthermore, although in the above-mentioned embodiment, the ion component removal filter 115 composed of alumina is used for removing the ion component, the hydrophilic organic solvent, or the like in the processing liquid, the present invention is not limited to the same. For example, the ion component can be recovered and removed using an ion exchanger or the like.
(6) Correspondence Between Elements in the Claims and Parts in Embodiments
In the following paragraphs, non-limiting examples of correspondences between various elements recited in the claims below and those described above with respect to various embodiments of the present invention are explained.
In the embodiments described above, the processing liquid nozzle 50 is an example of a supplier, the guard 24, the liquid recovery space 32, the recovery pipe 35, and the liquid recovery guide 42 are an example of a recovery system, the ion component removal filter 115 is an example of an ion remover, the mixing valve 117 is an example of a mixer, and the pipe 125 and the valve 125a are an example of a first circulating system.
Furthermore, in the embodiments described above, the impurity removal filter 114 is an example of an impurity remover, the purification tank 112 is an example of a storage, the concentration sensor S1 or the concentration sensor S2 is an example of a concentration detector, and the pipe 126, the valve 127, and the pump 128 are an example of a second circulating system.
As each of various elements recited in the claims, various other elements having configurations or functions described in the claims can be also used.
While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-239677 | Sep 2006 | JP | national |