Maintenance methods for semiconductor manufacturing equipment

Abstract

This improves safety during maintenance performed after opening up to the atmosphere in semiconductor manufacturing equipment that uses phosphorus-containing and chlorine-containing gases. [Solution] The maintenance method for semiconductor manufacturing equipment involves using a semiconductor manufacturing equipment that contains phosphorus and chlorine gases, and during maintenance of the inside of the equipment, the inside of the equipment is opened to the atmosphere, and then a fluorine-based solvent is supplied to the maintenance area.

Description

Technical Field

[0001] Relates to a maintenance method in a semiconductor manufacturing apparatus using a gas containing phosphorus and a gas containing chlorine.

Background Art

[0002] In semiconductor manufacturing apparatuses, various gases are used in wafer processing. For example, in the ion implantation apparatus disclosed in Patent Document 1, it use of gases such as PH3, BF3, N2, Cl2 or HCl is described when implanting dopant ions into a wafer.

[0003] In the chemical vapor deposition apparatus disclosed in Patent Document 2, use of a gas containing a gold halide gas, ammonia gas, nitrogen gas, hydrocarbon gas, chlorine gas, hydrogen chloride gas, hydrogen phosphide gas, oxygen gas or water vapor as an ambient gas is described.

[0004] With the operation of the apparatus, deposits derived from the used gases are generated. Such deposits increase over time. Since leaving the deposits unaddressed would interfere with wafer processing, maintenance such as cleaning the interior of the apparatus and replacing members is carried out at an appropriate timing.

[0005] Among the gases used in Patent Document 1 and Patent Document 2, deposits generated in a process using a phosphorus-containing gas pose a risk of ignition when exposed to air. As a countermeasure against ignition of phosphorus deposits, Patent Document 3 describes a method of wetting a member to which phosphorus deposits adhere with pure water to suppress ignition of the deposits.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

[0007] If the deposits consist solely of phosphorus, then, as described in Patent Document 3, wetting the deposits with pure water can suppress ignition that occurs when removing the deposits. However, if the same semiconductor manufacturing apparatus uses phosphorus-containing gas in one process and chlorine-containing gas in another process, that is, if both phosphorus-containing and chlorine-containing gases are used, then wetting the phosphorus deposits with pure water as a countermeasure against ignition caused by phosphorus deposits presents problems.

[0008] When phosphorus-containing gas and chlorine-containing gas are used, deposits originating from each gas are generated. If a large amount of chlorine-derived deposit is generated, supplying pure water to suppress the ignition of phosphorus-derived deposits will cause a chemical reaction between the water and chlorine, producing highly concentrated hydrochloric acid. High concentrations of hydrochloric acid corrode surrounding materials and can cause respiratory and skin damage to humans. For these reasons, using water to suppress phosphorus ignition when a large amount of chlorine-derived deposit has accumulated can significantly reduce safety during maintenance of the equipment.

[0009] This invention improves safety during maintenance performed after opening to the atmosphere in semiconductor manufacturing equipment that uses phosphorus-containing gas and chlorine-containing gas. [Means for solving the problem]

[0010] The maintenance method for semiconductor manufacturing equipment is: In semiconductor manufacturing equipment that uses a gas containing phosphorus and a gas containing chlorine, For maintenance of the inside of the device, the inside of the device is opened to the atmosphere, and then a fluorine-based solvent is supplied to the maintenance area.

[0011] By supplying fluorine-based solvents to maintenance areas, similar to supplying water, it is possible to suppress the ignition of phosphorus-derived deposits during their removal. Furthermore, unlike water supply, the supply of fluorinated solvents does not generate hydrochloric acid from chlorine-derived deposits. As a result, safety during maintenance of semiconductor manufacturing equipment can be improved.

[0012] Prior to opening the inside of the device to the atmosphere, the supply and discharge of an inert gas to the inside of the device is performed at least once.

[0013] This makes it possible to discharge chlorine-containing gases and chlorine-derived deposits that accumulate inside the device to the outside, allowing maintenance work after opening to the atmosphere to be carried out more safely.

[0014] When the inert gas is discharged, the chlorine concentration contained in the discharged gas is measured.

[0015] Measuring chlorine concentration allows for treatment tailored to the specific situation.

[0016] The semiconductor manufacturing apparatus is an ion beam irradiation apparatus equipped with a mass spectrometry unit, The maintenance unit is the mass spectrometry unit.

[0017] This improves safety during maintenance of the mass spectrometry section, where chlorine-derived and phosphorus-derived deposits tend to accumulate. [Effects of the Invention]

[0018] By supplying fluorine-based solvents to maintenance areas, similar to supplying water, it is possible to suppress the ignition of phosphorus-derived deposits during their removal. Furthermore, unlike water supply, the supply of fluorinated solvents does not generate hydrochloric acid from chlorine-derived deposits. As a result, safety during maintenance of semiconductor manufacturing equipment can be improved. [Brief explanation of the drawing]

[0019] [Figure 1] Shows a schematic plan view of an ion implantation apparatus [Figure 2] Shows a piping system diagram [Figure 3] Shows a flowchart related to a maintenance method

Embodiments for Carrying out the Invention

[0020] FIG. 1 is a schematic plan view of an ion implantation apparatus IM. In the plasma chamber 1, a plasma that serves as a source of an ion beam IB is generated. The ion beam IB is extracted from the plasma generated in the plasma chamber 1 to the beam line by the extraction electrode 2. The beam line is a transport path of the ion beam IB from the extraction electrode 2 to a processing chamber 9 described later.

[0021] The ion beam IB extracted from the extraction electrode 2 contains a plurality of ions. The mass spectrometry unit 3 and the analysis slit 4 disposed downstream thereof select ions according to mass in order to extract desired ions from the ion beam IB. The acceleration tube unit 5 accelerates or decelerates the ion beam IB selected by the mass spectrometry unit 3 and converts it into an ion beam IB having a desired energy.

[0022] Downstream of the acceleration tube unit 5, an energy analysis unit 6 is disposed. The energy analysis unit 6 removes ions of unnecessary energy components generated by charge conversion between the mass spectrometry unit 3 and the acceleration tube unit 5 or within the acceleration tube unit 5.

[0023] When the ion beam IB is cut in a plane perpendicular to the traveling direction of the ion beam IB, the cut surface of the ion beam IB extracted from the extraction electrode 2 is elliptical. Such an ion beam is called a spot beam. After passing through the energy analysis unit 6, the ion beam IB is periodically scanned along one direction by the scanning unit 7. By this scanning, the ion beam is apparently converted into an ion beam having a wide width in the scanning direction.

[0024] The scanned ion beam IB is incident on the parallelization section 8 and is magnetically deflected there. Magnetic deflection in the parallelization section 8 transforms the ion beam IB into one whose direction of propagation is aligned in the scanning direction. After passing through the parallelization section 8, the dimension of the ion beam IB in the scanning direction becomes longer than the diameter of the wafer W.

[0025] A wafer W, held in a wafer holder 10, is placed in the processing chamber 9. A drive mechanism 11 is connected to the wafer holder 10. The drive mechanism 11 adjusts the orientation of the wafer holder 10 relative to the ion beam IB and adjusts the irradiation angle of the ion beam IB onto the wafer W.

[0026] The X, Y, and Z axes shown are drawn relative to the trajectory of the ideal ion beam IB incident on processing chamber 9. The Z axis is parallel to the direction of propagation of the ion beam IB. The X and Y axes are orthogonal to each other with respect to the Z axis. The direction of each of the X, Y, and Z axes changes depending on the position of the ion beam being transported along the beamline.

[0027] The mass spectrometry unit 3 comprises a vacuum chamber 3a, an electromagnet E positioned inside it, and protective plates D, also known as dampers or liners. A pump P is located at the top of the vacuum chamber 3a to create a vacuum inside the chamber. A gas supply passage G is also connected to the vacuum chamber 3a to supply an inert gas such as nitrogen or argon.

[0028] The vacuum chamber 3a has a large volume sufficient to deflect the ion beam and perform mass spectrometry. During mass spectrometry, unwanted ionic components are excluded from the transport path of the ion beam IB and collide with the protective plate D. Due to these circumstances, residues originating from unwanted ionic components accumulate over a wide area in the vacuum chamber 3a. Furthermore, the mass spectrometry unit 3 is located upstream in the transport path of the ion beam IB from the extraction electrode 2 to the processing chamber 9. The temperature of the mass spectrometry unit 3 is lower than that of the plasma chamber 1. Due to these circumstances, deposits originating from ionized gases released from plasma chamber 1 tend to accumulate easily. Furthermore, a carbon fiber component is used as a protective plate D to prevent metal contamination of the wafer W. Unwanted ion components that collide with the carbon fiber component and some of the gases that leak out from the plasma chamber 1 are absorbed by the carbon fiber component and accumulated inside the component.

[0029] In the mass spectrometry section 3, where chlorine-derived and phosphorus-derived deposits tend to accumulate, a fluorinated solvent is supplied instead of water. Examples of fluorinated solvents include the SOLBLE series manufactured and sold by SOLVEX and Flurinert manufactured and sold by 3M, both of which are fluorinated inert liquids. These fluorinated solvents are widely used as cleaning fluids and coolants for electronic equipment and also function as fire extinguishing agents.

[0030] During maintenance of the vacuum chamber 3a, valves V1 and V2 are closed to create a closed space containing the mass spectrometry unit 3. Note that the arrangement of valves V1 and V2 is not limited to the configuration shown. Any arrangement is acceptable as long as it creates a closed space containing the mass spectrometry unit 3, which is the target of maintenance. An inert gas such as nitrogen gas or argon is introduced into the closed space containing the mass spectrometry unit 3 through the gas supply channel G, and the pressure inside the closed space is set to atmospheric pressure. Next, access is made to the inside of the ion implanter IM, and the door 12 of the mass spectrometry unit 3 is opened. The illustrated door 12 is shown as a hinged door, but it is not limited to this configuration. For example, the door 12 could be fixed to the vacuum chamber 3a with bolts, and the door 12 could be opened and closed by opening and closing the bolts.

[0031] After opening door 12, a fluorine-based solvent is supplied to the maintenance area. Maintenance areas include, for example, the wall surface of the vacuum chamber 3a, the yoke and flange of the electromagnet E, and the protective plate D. The fluorine-based solvent is supplied by putting it in a spray bottle and spraying it. Alternatively, the fluorine-based solvent may be supplied by wiping the maintenance area with a cloth soaked in the fluorine-based solvent.

[0032] By supplying a fluorine-based solvent to the maintenance area and wetting the phosphorus-derived deposits, ignition during deposit removal can be suppressed. In addition, the extinguishing effect of the fluorine-based solvent effectively suppresses ignition from the deposits. On the other hand, unlike water supply, hydrochloric acid is not generated from chlorine-derived deposits when supplying fluorinated solvents. Using these fluorine-based solvents during maintenance can improve safety during the maintenance process. Furthermore, when the vacuum chamber 3a is opened to the atmosphere, water components in the air may react with chlorine-derived deposits that accumulate in the vacuum chamber 3a. Although there remains a risk that a small amount of hydrochloric acid may be produced as a result of this reaction, the amount is extremely small compared to the amount of hydrochloric acid produced by actively adding water, and therefore does not pose a safety problem.

[0033] There is a risk that chlorine-containing gas may be accumulating in the vacuum chamber 3a. In addition, there is a risk that some of the chlorine-derived deposits accumulating in the vacuum chamber 3a and some of the chlorine components remaining in the protective plate D may vaporize, generating chlorine gas inside the vacuum chamber 3a. If the chlorine concentration in these gases is high, there are concerns that opening the vacuum chamber 3a to the atmosphere could have adverse effects on human health.

[0034] Due to the above concerns, a chlorine concentration meter will be installed in the vacuum chamber 3a to measure the chlorine concentration inside the vacuum chamber 3a before opening it to the atmosphere. Furthermore, if the chlorine concentration is high based on the chlorine concentration measurement results, the supply and discharge of inert gas to the vacuum chamber 3a may be performed one or more times to expel the chlorine gas. Figure 2 is a piping diagram related to the expulsion of chlorine gas.

[0035] To expel the chlorine gas, valves V1, V2, and V4 are closed. Then, valve V3 is opened to introduce an inert gas (e.g., nitrogen gas) into the vacuum chamber 3a. After the vacuum chamber 3a is filled with the inert gas, valve V3 is closed. Next, valve V4 is opened to discharge the inert gas from the vacuum chamber 3a. At this time, the chlorine gas is discharged to the outside of the vacuum chamber 3a along with the inert gas.

[0036] A chlorine concentration meter M is installed in the gas discharge line. Based on the measurement results from the chlorine concentration meter M, the supply of inert gas to the mass spectrometry unit 3 and the discharge of inert gas from the mass spectrometry unit 3 are repeated until the chlorine concentration falls below the standard value. Finally, when the chlorine concentration falls below the predetermined level, inert gas is introduced into the vacuum chamber 3a, and the pressure inside the vacuum chamber 3a is brought to atmospheric pressure.

[0037] By supplying inert gas to the mass spectrometry unit 3 and discharging the inert gas from the mass spectrometry unit 3 at least once, the vacuum chamber 3a can be safely opened to the atmosphere.

[0038] Although the maintenance method for semiconductor manufacturing equipment involves supplying fluorine-based solvents to maintenance areas, it is not necessary to supply fluorine-based solvents to maintenance areas if safety during maintenance can be ensured.

[0039] For example, the amount of chlorine deposit inside the vacuum chamber 3a can be estimated from the chlorine concentration of the gas discharged from the vacuum chamber 3a. If the chlorine concentration measurement results indicate that the amount of chlorine buildup is small, even if the maintenance area is wet with water to suppress phosphorus ignition, the likelihood of generating hydrochloric acid at a level that could harm the human body is low, and safety during maintenance is ensured.

[0040] Considering this point, depending on the hydrochloric acid concentration, you may choose to use either water or a fluorine-based solvent during maintenance. The flowchart in Figure 3 shows the procedures involved in maintenance. First, an inert gas is supplied to the vacuum chamber 3a (S1). Next, the inert gas is discharged from the vacuum chamber 3a (S2). At this time, the chlorine concentration in the discharged gas is measured and compared with the reference value R (S3). Based on the comparison results, if the chlorine concentration is above the standard value R, a fluorine-based solvent will be supplied during maintenance (S4). If the chlorine concentration is below the standard value R, water will be supplied during maintenance (S5).

[0041] In the flowchart shown in Figure 3, the inert gas is supplied and discharged only once. However, if the chlorine concentration in treatment S3 is above the standard value R, the supply and discharge of the inert gas may be repeated before supplying the fluorine-based solvent. The number of times the inert gas is supplied and discharged can be predetermined, and after performing the predetermined number of operations, the choice of using a fluorinated solvent or water can be made based on the comparison between the chlorine concentration and the standard value R.

[0042] The comparison results of process S3 in the flowchart of Figure 3 should be displayed on the device's operation screen so that the device operator can recognize them. Alternatively, instead of displaying the results on the operation screen, different colored lamps may be provided, and the corresponding lamp should be illuminated according to the comparison results.

[0043] In the above embodiment, a maintenance method for the mass spectrometry unit 3 of the ion implanter IM was described, but the use of fluorine-based solvents is not limited to the mass spectrometry unit 3. For example, fluorine-based solvents may be used for maintenance of the plasma chamber 1 or the extraction electrode 2, which constitute the ion source.

[0044] In addition to ion implantation equipment, fluorine-based solvents may also be used during maintenance of surface modification equipment that performs surface modification and microfabrication of wafers, thin films, etc., using an ion beam. Ion implantation equipment and the surface processing equipment mentioned here are broadly referred to as ion beam irradiation equipment. Furthermore, in addition to ion beam irradiation devices such as ion implanters, fluorine-based solvents may also be used during maintenance of semiconductor manufacturing equipment such as film deposition systems and sputtering systems that use chlorine-containing gases and phosphorus-containing gases in combination.

[0045] Furthermore, it goes without saying that the present invention is not limited to the embodiments described above, and various modifications are possible without departing from its spirit. [Explanation of Symbols]

[0046] 3 Mass spectrometry section 3a Vacuum Chamber D Protective plate G Gas supply channel P Vacuum pump IM Ion Implantation System (Semiconductor Manufacturing Equipment)

Claims

1. In semiconductor manufacturing equipment that uses a gas containing phosphorus and a gas containing chlorine, A maintenance method for semiconductor manufacturing equipment, comprising opening the inside of the equipment to the atmosphere and then supplying a fluorine-based solvent to the maintenance area during internal maintenance of the equipment.

2. A method for maintaining a semiconductor manufacturing apparatus according to claim 1, wherein, prior to opening the inside of the apparatus to the atmosphere, an inert gas is supplied to and discharged from the inside of the apparatus at least once.

3. A maintenance method for a semiconductor manufacturing apparatus according to claim 2, comprising measuring the chlorine concentration contained in the discharged gas when the inert gas is discharged.

4. The semiconductor manufacturing apparatus is an ion beam irradiation apparatus equipped with a mass spectrometry unit, The maintenance method for a semiconductor manufacturing apparatus according to claim 1, wherein the maintenance part is the mass spectrometry unit.

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