JP4377285B2 - Substrate processing method and substrate processing apparatus - Google Patents

Description

  The present invention relates to a substrate processing method and a substrate processing apparatus method for removing unnecessary resist from the surface of a substrate.

  Semiconductor device manufacturing processes include a process of selectively etching an oxide film or the like formed on the surface of a semiconductor wafer (hereinafter simply referred to as “wafer”), and impurities such as phosphorus, arsenic, and boron on the surface of the wafer. A step of locally implanting (ions) is included. In these processes, a resist made of an organic material such as a photosensitive resin is patterned on the outermost surface of the wafer in order to prevent etching or ion implantation to an undesired portion, and a portion where etching or ion implantation is not desired is formed by the resist. Masked. Since the resist patterned on the wafer becomes unnecessary after the etching or ion implantation, after the etching or ion implantation, a resist removing process is performed to remove the unnecessary resist on the wafer. .

The resist removal process can be achieved, for example, by removing the resist by ashing (ashing) with an ashing device, and then carrying the wafer into a cleaning device to remove the resist residue after ashing from the surface of the wafer. In the ashing apparatus, for example, a processing chamber containing a wafer to be processed is made an oxygen gas atmosphere, and microwaves are emitted into the oxygen gas atmosphere. As a result, oxygen gas plasma (oxygen plasma) is generated in the processing chamber, and this oxygen plasma is irradiated onto the wafer surface, whereby the resist on the wafer surface is decomposed and removed. On the other hand, in the cleaning apparatus, for example, a chemical solution such as APM (ammonia-hydrogen peroxide mixture) is supplied to the wafer surface, and the wafer surface is cleaned with the chemical solution (resist residue removal process). As a result, the resist residue adhering to the surface of the wafer is removed.
Japanese Patent Laid-Open No. 9-45610

  However, when high dose ion implantation is performed, the resist surface is altered (hardened), and thus ashing by high energy plasma or ashing for a long time is required. However, when the wafer W is irradiated with high-energy plasma or when the wafer W is irradiated with the plasma for a long time, a portion of the wafer surface not covered with the resist (for example, exposed oxide film) is damaged. End up.

  In addition, in order to suppress damage to the substrate, ashing is performed conservatively (energy and / or time), and after the ashing, the resist is formed using a strong oxidizing chemical solution such as a mixed solution of sulfuric acid and hydrogen peroxide solution. It is conceivable to peel off. However, in this method, in addition to the ashing device and the cleaning device, a device for performing treatment with a chemical solution is required. In addition, the time required to remove the resist becomes long.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a substrate processing that can satisfactorily remove a resist formed on a substrate (particularly, a resist having a cured layer formed on the surface by ion implantation) without damaging the surface of the substrate. It is to provide a method and a substrate processing apparatus.

In order to achieve the above object, according to the first aspect of the present invention, after the ion implantation step for implanting impurities into the surface of the substrate (W), a resist having a hardened layer formed on the surface by implantation of the impurities is applied to the surface of the substrate. the substrate processing method for removing from a surface to droplets of jets supplied droplet jet supply process of the substrate to be processed (S2), on the surface of the substrate after the jet of droplets supplying step, the And a resist stripping solution supplying step (S3) for supplying a resist stripping solution for stripping the resist from the surface.

In addition, the alphanumeric characters in parentheses represent corresponding components in the embodiments described later. The same applies hereinafter.
According to the first aspect of the present invention, by supplying a jet of droplets to the surface of the substrate, irregularities due to the destruction of the hardened layer are formed on the surface of the resist, and then a resist stripping solution is supplied to the surface of the substrate. Is done. Since the hardened layer on the surface of the resist is broken, the resist stripping solution supplied to the surface of the substrate can penetrate into the resist from the broken portion of the hardened layer. Therefore, even if the substrate to be processed is not subjected to the ashing process for removing the cured layer, the resist having the cured layer formed on the surface of the substrate can be satisfactorily removed by the resist stripping solution. it can. Further, since ashing is unnecessary, it is possible to avoid the problem of damage to the portion of the substrate surface not covered with the resist due to ashing.

The droplet jet supply step may be a step of supplying a jet of pure water droplets to the surface of the substrate to be processed as described in claim 2, or as described in claim 3. Alternatively, a step of supplying a jet of resist stripping liquid droplets to the surface of the substrate to be processed may be used.
According to a fourth aspect of the present invention, there is provided a substrate processing apparatus used for removing a resist having a hardened layer formed on the surface thereof by implanting the impurities after the ion implantation step of implanting the impurities into the surface of the substrate. The substrate holding means (1) for holding the substrate, the droplet jet supply means (3) for supplying a jet of droplets to the surface of the substrate held by the substrate holding means, and the substrate holding means The resist stripping solution supply means (2) for supplying the resist stripping solution to the surface of the held substrate, the droplet jet supply means and the resist stripping solution supply means are controlled, and the droplet jetting by the droplet jet supply means is controlled. And a means (4) for supplying the resist stripping solution by the resist stripping solution supplying means after the jet flow.

  In the apparatus having such a configuration, the substrate processing method according to claims 1 to 3 can be executed, and the effect described in relation to claim 1 can be achieved.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a diagram schematically showing the configuration of a substrate processing apparatus according to an embodiment of the present invention. This substrate processing apparatus is, for example, a resist that has become unnecessary from the surface of a wafer W after an ion implantation process for implanting impurities into the surface of a semiconductor wafer W (hereinafter simply referred to as “wafer W”), which is an example of a substrate. Is a single-wafer type apparatus that performs a resist stripping process for stripping and removing the wafer W. The spin chuck 1 rotates while holding the wafer W substantially horizontally, and the surface of the wafer W held by the spin chuck 1 ( An SPM nozzle 2 for supplying SPM (sulfuric acid / hydrogen peroxide mixture) as a resist stripping solution to the upper surface), and a pure water droplet on the surface of the wafer W held by the spin chuck 1 And a two-fluid nozzle 3 for supplying the jet.

  The spin chuck 1 is fixed to the upper end of a rotating shaft 12 rotated by a chuck rotation driving mechanism 11, and has a substantially disk-shaped spin base 13 and a plurality of peripheral portions of the spin base 13 at substantially equal angular intervals. And a plurality of clamping members 14 for clamping the substrate W in a substantially horizontal posture. By rotating the rotating shaft 12 by the chuck rotation drive mechanism 11 while the wafer W is held by the plurality of holding members 14, the wafer W is rotated together with the spin base 13 while maintaining a substantially horizontal posture. It can be rotated around the central axis of the shaft 12.

The spin chuck 1 is not limited to such a configuration. For example, the back surface (non-device surface) of the wafer W is vacuum-sucked to hold the wafer W in a horizontal posture, and in that state. A vacuum chuck of a vacuum suction type that can rotate the wafer W held by rotating around a vertical axis may be employed.
The SPM nozzle 2 is composed of, for example, a straight nozzle that discharges SPM in a continuous flow state. An SPM supply pipe 21 is connected to the SPM nozzle 2, and a high-temperature SPM of about 100 ° C. or higher capable of satisfactorily peeling the resist on the surface of the wafer W is supplied from the SPM supply pipe 21. ing. An SPM valve 22 for controlling the supply of SPM to the SPM nozzle 2 is interposed in the middle of the SPM supply pipe 21.

  The SPM nozzle 2 has a basic form as a scan nozzle that can change the SPM supply position on the surface of the wafer W. Specifically, a first rotation shaft 23 is disposed substantially along the vertical direction on the side of the spin chuck 1, and the SPM nozzle 2 is disposed from the upper end portion of the first rotation shaft 23. It is attached to the tip of the first arm 24 that extends substantially horizontally. An SPM nozzle drive mechanism 25 is coupled to the first rotation shaft 23 to rotate the first rotation shaft 23 around a central axis within a predetermined angle range. By inputting a driving force from the SPM nozzle drive mechanism 25 to the first rotation shaft 23 and rotating the first rotation shaft 23 within a predetermined angle range, the wafer W held on the spin chuck 1 is rotated. The first arm 24 can be swung over the upper surface of the wafer W. Accordingly, the SPM supply position from the SPM nozzle 2 is scanned (moved) on the surface of the wafer W held by the spin chuck 1. be able to.

  The two-fluid nozzle 3 is connected to a pure water supply pipe 31 to which pure water from a pure water supply source is supplied and a nitrogen gas supply pipe 32 to which high-pressure nitrogen gas from a nitrogen gas supply source is supplied. Yes. When pure water and high-pressure nitrogen gas are simultaneously supplied to the two-fluid nozzle 3, pure water and high-pressure nitrogen gas are mixed to form fine droplets of pure water, and the pure water droplets are jetted. And supplied to the surface of the wafer W. A pure water valve 33 for controlling the supply of pure water to the two-fluid nozzle 3 is interposed in the middle of the pure water supply pipe 31. A nitrogen gas valve 34 for controlling the supply of nitrogen gas to the two-fluid nozzle 3 is interposed in the middle of the nitrogen gas supply pipe 32.

  On the side of the spin chuck 1, a second rotation shaft 35 is disposed substantially along the vertical direction, and the two-fluid nozzle 3 extends substantially horizontally from the upper end of the second rotation shaft 35. The second arm 36 is attached to the distal end portion. Coupled to the second rotation shaft 35 is a two-fluid nozzle drive mechanism 37 that rotates the second rotation shaft 35 around a central axis within a predetermined angle range. The wafer held on the spin chuck 1 is input by inputting a driving force from the two-fluid nozzle driving mechanism 37 to the second rotating shaft 35 and rotating the second rotating shaft 35 within a predetermined angular range. The second arm 36 can be swung above W, and along with this, the jet of pure water droplets from the two-fluid nozzle 3 on the surface of the wafer W held by the spin chuck 1. The supply position can be scanned (moved).

  FIG. 2 is a schematic cross-sectional view showing the configuration of the two-fluid nozzle 3. The two-fluid nozzle 3 is an internal mixing type two-fluid nozzle, and includes a gas introduction part 301, a liquid introduction part 302, and a droplet formation / discharge part 303. The gas introduction part 301, the liquid introduction part 302, and the droplet formation discharge part 303 all have a tube shape, and these are connected in series to form the two-fluid nozzle 3.

The droplet forming / discharging unit 303 is connected to the lower end of the liquid introducing unit 302, and is connected to the tapered portion 304 whose inner diameter becomes smaller toward the lower side and the lower end of the tapered portion 304, and has a uniform inner diameter. And a straight portion 305 having a shape.
The gas introduction part 301 includes a large diameter part that engages with the upper part of the liquid introduction part 302, and a small diameter part that continues to the lower part of the large diameter part and reaches the internal space of the tapered part 304 of the droplet forming and discharging part 303 A tapered gas introduction path 306 is formed in the inside, and an inlet thereof forms a gas introduction port 307. A nitrogen gas supply pipe 32 (see FIG. 1) is connected to the gas introduction port 307.

  A liquid introduction port 308 to which the pure water supply pipe 31 (see FIG. 1) is connected is formed in the liquid introduction part 302 so as to open to the side. The liquid introduction port 308 has a small diameter of the gas introduction part 301. And a ring-shaped space SP1 between the liquid introduction portion 302 and the inner wall of the liquid introduction portion 302. This space SP1 is an internal space SP3 (mixed space) of the tapered portion 304 of the droplet forming / discharging unit 303 via a ring-shaped space SP2 between the small diameter portion of the gas introducing unit 301 and the inner wall of the droplet forming / discharging unit 303. Room).

  In the internal mixing type two-fluid nozzle 3, nitrogen gas supplied from the gas introduction port 307 and pure water supplied from the liquid introduction port 308 via the spaces SP1 and SP2 are mixed in the space SP3, As a result, droplets are formed. This droplet is accelerated by the taper portion 304 and is ejected vigorously toward the wafer W held by the spin chuck 1 through the straight portion 305. This jet of droplets has very good straightness due to the action of the straight portion 305.

FIG. 3 is a block diagram showing an electrical configuration of the substrate processing apparatus. The substrate processing apparatus further includes a control device 4 having a configuration including a microcomputer.
The control device 4 is connected to the chuck rotation drive mechanism 11, the SPM nozzle drive mechanism 25, the two-fluid nozzle drive mechanism 37, the SPM valve 22, the pure water valve 33, and the nitrogen gas valve 34 as control targets. The control device 4 controls the operations of the chuck rotation drive mechanism 11, the SPM nozzle drive mechanism 25, and the two-fluid nozzle drive mechanism 37 according to a predetermined program, and also the SPM valve 22, the pure water valve 33, and the nitrogen gas valve 34. Controls the opening and closing of.

  FIG. 4 is a diagram for explaining the resist stripping process. The wafer W to be processed is carried in by a transfer robot (not shown) and is held by the spin chuck 1 with the surface on which the resist is formed facing upward (step S1). Note that the wafer W to be processed has not been subjected to a process for ashing (ashing) the resist, and a hardened layer altered by ion implantation is formed on the surface of the resist.

  In the resist stripping process, first, the chuck rotation drive mechanism 11 is controlled to rotate the wafer W held on the spin chuck 1 at a predetermined rotation speed (for example, 100 rpm). Further, the two-fluid nozzle driving mechanism 37 is controlled, and the two-fluid nozzle 3 is moved above the wafer W held by the spin chuck 1 from the standby position set on the side of the spin chuck 1. Thereafter, the pure water valve 33 and the nitrogen gas valve 34 are opened, and a jet of pure water droplets is discharged from the two-fluid nozzle 3. On the other hand, the two-fluid nozzle drive mechanism 37 is controlled to swing the second arm 36 within a predetermined angular range. As a result, the supply position on the surface of the wafer W to which the jet of droplets from the two-fluid nozzle 3 is guided moves within an area extending from the rotation center of the wafer W to the peripheral edge of the wafer W while drawing an arc-shaped locus. Then, a jet of pure water droplets is supplied evenly over the entire surface of the wafer W (step S2). The cured layer formed on the surface of the resist is destroyed by impact when the jet of pure water droplets collides, and fine irregularities are formed on the surface of the resist.

When the reciprocating scan of the jet flow supply position is performed a predetermined number of times, the pure water valve 33 and the nitrogen gas valve 34 are closed. Then, the two-fluid nozzle 3 is returned to the standby position on the side of the spin chuck 1 from above the wafer W.
Next, the SPM nozzle driving mechanism 25 is controlled, and the SPM nozzle 2 is moved above the wafer W held by the spin chuck 1 from a standby position set on the side of the spin chuck 1. Then, the SPM valve 22 is opened, and high temperature SPM is supplied from the SPM nozzle 2 to the surface of the rotating wafer W. On the other hand, the SPM nozzle drive mechanism 25 is controlled to swing the first arm 24 within a predetermined angle range. As a result, the supply position on the surface of the wafer W from which the SPM from the SPM nozzle 2 is guided moves within a range from the rotation center of the wafer W to the peripheral edge of the wafer W while drawing an arc-shaped locus, and the wafer W SPM is supplied uniformly over the entire surface (step S3).

  Since the hardened layer on the surface of the resist is broken by the jet of pure water droplets, the high-temperature SPM supplied to the surface of the wafer W penetrates into the resist from the broken portion of the hardened layer. be able to. Therefore, even if the wafer W to be processed has not been subjected to the ashing process for removing the hardened layer, the unnecessary resist formed on the surface of the wafer W can be satisfactorily removed by the oxidizing power of the SPM. Can do.

When the reciprocating scan of the SPM supply position is performed a predetermined number of times, the supply of SPM to the wafer W is stopped, and the SPM nozzle 2 is returned to the side retracted position of the spin chuck 1.
Thereafter, pure water (deionized pure water) is supplied to the surface of the wafer W, and SPM adhering to the surface of the wafer W is washed away with pure water (step S4). When the supply of pure water is continued for a certain period of time, the supply of DIW is stopped. Subsequently, the wafer W is rotated at a high rotation speed (for example, 3000 rpm), and DIW adhering to the wafer W is centrifugally applied. A process of spinning and drying (spin dry process) is performed (step S5). When this process is completed, the chuck rotation drive mechanism 11 is controlled to stop the rotation of the wafer W by the spin chuck 1, and then the processed wafer W is unloaded by a transfer robot (not shown) (step S6).

  As described above, according to this embodiment, by supplying a jet of pure water droplets to the surface of the wafer W, irregularities due to the destruction of the hardened layer are formed on the surface of the resist. Hot SPM is supplied to the surface. Since the hardened layer on the surface of the resist is broken, the high temperature SPM supplied to the surface of the wafer W can penetrate into the resist from the surface of the broken hardened layer. Therefore, even if the wafer W to be processed is not subjected to the ashing process for removing the hardened layer, the unnecessary resist formed on the surface of the wafer W can be satisfactorily removed by the oxidizing power of the SPM. Can do. Further, since ashing is unnecessary, it is possible to avoid the problem of damage to the portion of the surface of the wafer W not covered with the resist due to ashing.

  As mentioned above, although several embodiment of this invention was described, this invention can also be implemented with another form. For example, in the above embodiment, a jet of pure water droplets is supplied to the surface of the wafer W in order to form irregularities on the surface of the resist. However, instead of pure water, a resist stripping solution such as SPM is used. Is supplied to the two-fluid nozzle 3 and a jet of a resist stripping liquid droplet is supplied from the two-fluid nozzle 3 to the surface of the wafer W, whereby irregularities due to destruction of the hardened layer may be formed on the surface of the resist.

Further, in place of the two-fluid nozzle 3, a high-pressure jet nozzle that pressurizes and discharges pure water or a resist stripping solution is provided, and the pure water or the resist stripping solution discharged from the high-pressure jet nozzle causes the resist surface to be exposed to the surface of the resist. Irregularities due to destruction of the hardened layer may be formed.
Further, in the above embodiment, the supply of the droplet jet to the surface of the wafer W and the supply of the SPM are performed by the same apparatus, but the supply of the droplet jet to the surface of the wafer W and the supply of the SPM May be performed by different devices.

Furthermore, although SPM is used as the resist stripping solution, not only SPM but also other types of chemicals such as sulfuric acid ozone produced by mixing sulfuric acid and ozone gas may be used.
Further, the substrate to be processed is not limited to the wafer W in which the impurity is locally implanted on the surface by irradiating the surface of the resist pattern with the impurity ions, and the resist pattern is formed. It may be a wafer W in which the thin film is selectively etched by supplying an etching solution onto a thin film such as an oxide film, and the type of the substrate is also a glass substrate for a liquid crystal display device, a glass for a plasma display panel. Other types of substrates such as substrates, glass substrates for photomasks, and substrates for magnetic / optical disks may be used.

  In addition, various design changes can be made within the scope of the matters described in the claims.

1 is a diagram schematically showing a configuration of a substrate processing apparatus according to an embodiment of the present invention. It is an illustration sectional view showing the composition of a two fluid nozzle. It is a block diagram which shows the electric constitution of this substrate processing apparatus. It is a figure for demonstrating a resist peeling process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Spin chuck 2 SPM nozzle 3 Two-fluid nozzle 4 Controller W Wafer

Claims (4)

A substrate processing method for removing from a surface of a substrate a resist having a hardened layer formed on the surface by implantation of the impurity after an ion implantation step of implanting impurities into the surface of the substrate,
A droplet jet supplying step for supplying a droplet jet to the surface of the substrate to be processed;
A substrate processing method comprising: a resist stripping solution supplying step of supplying a resist stripping solution for stripping a resist from the surface of the substrate after the droplet jet supplying step.   2. The substrate processing method according to claim 1, wherein the droplet jet supplying step is a step of supplying a jet of pure water droplets to the surface of the substrate to be processed.   2. The substrate processing method according to claim 1, wherein the droplet jet supplying step is a step of supplying a jet of a resist stripping liquid droplet to the surface of a substrate to be processed. A substrate processing apparatus used for removing from a surface of a substrate a resist having a hardened layer formed on the surface by the implantation of the impurity after an ion implantation step of implanting impurities into the surface of the substrate,
Substrate holding means for holding the substrate;
A droplet jet supply means for supplying a jet of droplets to the surface of the substrate held by the substrate holding means;
A resist stripper supply means for supplying a resist stripper to the surface of the substrate held by the substrate holder;
Means for controlling the droplet jet supply means and the resist stripping liquid supply means to supply the resist stripping liquid by the resist stripping liquid supply means after the supply of the droplet jet by the droplet jet supply means. A substrate processing apparatus including the substrate processing apparatus.

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