TWI503877B - Substrate processing method - Google Patents

Description

Substrate processing method [Cross-reference to related patent applications]

The present invention claims priority to Korean Patent Application No. 10-2011-005, 1974, filed on May 31, 2011, the disclosure of which is hereby incorporated by reference.

The present invention relates to a substrate processing system and a substrate processing method using the same, and more particularly to a substrate processing for removing impurities, a hafnium oxide layer, and fumes from a substrate after etching the substrate. System and substrate processing method using the system.

As semiconductor devices become more and more integrated, isolation techniques for electrically isolating adjacent devices are becoming more and more important. The shallow trench isolation (STI) formation method is one type of isolation technique used in semiconductor processing, which forms a trench that limits the active area in the semiconductor substrate and forms an isolation layer by burying the inside of the trench with an insulating material. .

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view showing a method of forming a typical isolation layer.

Referring to FIG. 1, a pad oxide layer and a nitride layer are sequentially formed on a semiconductor substrate 10. A photoresist pattern (not shown) is formed on the nitride layer, and then the nitride pattern 30 is formed by patterning the nitride layer with the photoresist pattern. The pad oxide layer 20 and the semiconductor substrate 10 are etched by using the nitride pattern 30 as an etch mask to form the pad oxide pattern 20 and the trench 40 (the area where the semiconductor substrate 10 is restricted).

In the subsequent process, the photoresist pattern is removed by ashing, The etching by-product and the like are removed by a wet cleaning method, the insulating material is buried inside the trench 40, and then the nitride pattern 30 and the pad oxide pattern 20 are removed, thereby completing the isolation layer.

However, when the lower layer is formed as a PSG layer, a BPSG layer, an SOD layer or a relatively soft oxide layer, damage occurs in the lower layer due to the washing liquid in the wet cleaning method (that is, the lower layer is excessively etched).

In order to overcome these limitations, dry cleaning with HF gas (instead of wet cleaning) as an alternative process has recently gained increasing attention. However, when dry cleaning is applied, there is a time lag between the various processes due to the transfer between the substrate-forming etching device and the dry cleaning device used after etching, and therefore, an impurity called smoke is generated inside the pattern.

2 is a plan view schematically showing a state in which the trench 40 is formed in the semiconductor substrate 10 by an etching device. When the semiconductor substrate 10 is transferred to the dry cleaning device, the semiconductor substrate 10 is exposed to the atmosphere, and thus is generated inside the trench 40. Smoke 50.

As illustrated, the flue gas 50 is produced on the semiconductor substrate 10 and analysis by XPS/AES shows that the flue gases 50 contain SiO ₂ . This can be understood as a state in which a halogen component such as F, Cl, and Br in the etching gas used in the etching process remains inside the trench 40, and then when the halogen component is exposed to the atmosphere It reacts with moisture in the atmosphere to form a solid hydrate. Such flue gas becomes a problem in any process in which the STI process and patterning are applied after dry cleaning (for example, a process of forming a gate line and a bit line).

In other words, if the etch by-product is washed by wet cleaning (as a subsequent process after etching), hydrolysis with H ₂ O ₂ or a buffered oxide etchant (BOE) prevents the formation of smoke. However, as described above, it is impossible to apply wet washing due to damage occurring in the lower layer. Conversely, if dry cleaning is used, it will cause smoke.

Therefore, there is a need to develop new substrate processing systems to prevent damage in the underlying layers and to additionally remove both etch byproducts and fumes.

Embodiments of the present invention provide a substrate processing system having an improved structure that prevents damage in the underlying layer and effectively removes both etch byproducts and flue gas, and provides a substrate processing method using the system.

In one aspect, the substrate processing system includes a wet cleaning module and a dry cleaning module. The wet cleaning module is configured to supply a washing liquid to the substrate, thereby cleaning the surface of the substrate and drying the cleaned substrate. The dry cleaning module is configured to spray a cleaning gas onto the substrate to etch a layer of ruthenium oxide formed on the substrate, the cleaning gas containing HF gas.

According to an embodiment of the present invention, the substrate processing system may further include: a cassette module for accommodating the substrate before or after processing the substrate; and an atmospheric transfer module for transferring the substrate received in the cassette module; a transfer module connected to the dry cleaning module for transferring the substrate to the dry cleaning module under vacuum; and a load lock module connected to the vacuum transfer module and changing the pressure between the atmospheric state and the vacuum state .

In another aspect, a substrate processing method includes: performing a dry cleaning process, spraying a cleaning gas onto a substrate to remove cerium oxide formed on the substrate a layer, the cleaning gas contains HF gas; and performing a wet cleaning process, supplying a washing liquid to the substrate to clean the surface of the substrate, and drying the substrate.

According to another embodiment of the present invention, the substrate processing method may further include: performing a preliminary wet cleaning process of supplying a washing liquid to the substrate to clean the surface of the substrate and drying the substrate before the dry cleaning process.

According to another embodiment of the present invention, the preliminary wet cleaning process may include removing organic material from a surface of the substrate, and the wet cleaning process may include removing flue gas generated from an etching gas residue containing a halogen compound .

According to an embodiment of the present invention, the underlying layer can be prevented from being damaged, and the yttrium oxide layer, the etching by-product, and the flue gas can be effectively removed from the substrate.

The above features and advantages and other features and advantages of the present invention will become more apparent from the Detailed Description of the Description.

Hereinafter, a substrate processing system and method according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 is a schematic configuration diagram of a substrate processing system in accordance with an embodiment of the present invention. 4 is a schematic configuration diagram of the wet cleaning module of FIG. 3. Figure 5 is a schematic configuration diagram of the dry cleaning module of Figure 3.

3 to 5, a substrate processing system 1000 according to an embodiment of the present invention includes a cassette module 100, an atmospheric transfer module 200, a wet cleaning module 300, a load lock module 400, a vacuum transfer module 500, and dry cleaning. Module 600.

The cassette module 100 houses the substrate before and after the processing. In this embodiment, four card modules are arranged in a row, and the four card modules are Both of them accommodate the substrate before the processing, and the other two cassette modules accommodate the substrate after the processing. As used herein, "processing" means a cleaning (or etching) process performed by the dry cleaning module 600 and the wet cleaning module 300.

The atmospheric transfer module 200 transfers the substrate placed in the cassette module 100 or transfers the substrate to the cassette module 100. The atmospheric transfer module 200 is coupled to the four cassette modules and includes a transfer robot 210. The transfer robot 210 moves in the direction in which the four cassette modules are disposed, and transfers the substrate between the buffer member 220 and the cassette module 100.

The cushioning member 220 temporarily houses the substrate, and the cushioning member 220 is disposed between one of the wet cleaning modules 300 to be described below. The substrate placed in the buffer component 220 is transferred to the wet cleaning module 300 or the load lock module 400 by the auxiliary transfer robot 230. On the other hand, the substrate transferred from the wet cleaning module 300 and the load lock module 400 is temporarily placed in the buffer component 220. To this end, a plurality of grooves for accommodating the substrate are prepared in the cushioning member 220.

In the wet process, the wet cleaning module 300 cleans the substrate. In this embodiment, a pair of wet cleaning modules are provided. Referring to FIG. 4, the wet cleaning module 300 includes a chamber 310, a base 320, and a lotion sprayer 330. The susceptor 320 is rotatably disposed inside the chamber 310, and the substrate W is placed on the susceptor 320. The lotion sprayer 330 is disposed on the upper portion of the susceptor 320 and supplies the washing liquid to the substrate W. In this case, the lotion can be appropriately changed depending on the purpose of cleaning (that is, according to the material to be removed from the surface of the substrate by washing). For example, the lotion may be ultrapure water, deionized water, NH ₄ OH solution, ozone water, or the like. Also, the wet scrubbing module 300 can further include a rinsing solution supply that supplies a rinsing solution (eg, an ultra pure rinsing solution) to the substrate to rinse the substrate after cleaning. Alternatively, the wet scrubbing module 300 may not include a separate rinsing solution supply, but allows the rinsing sprinkler 330 to supply the rinsing solution.

The substrate is washed by supplying a rinsing solution to the substrate while rotating the susceptor 320, and the rinsing solution is spread over the entire surface of the substrate. Subsequently, the substrate is rinsed by supplying a rinsing solution to the substrate, and then the substrate is dried by continuously rotating the susceptor 320 for a certain time. At this time, the substrate may be heated, or an inert gas may be supplied to the substrate to achieve smooth drying. To this end, the wet cleaning module 300 may further include a heater (not shown) and an inert gas sprayer (not shown).

The amount of wash solution (or rinse solution) supplied to the substrate can be controlled so that the spread of the wash liquid only spreads over the surface (top) of the substrate without flowing down or flowing along the side surface to the bottom of the substrate. That is, by appropriately controlling the amount of the washing liquid in consideration of the rotation speed of the substrate, the centrifugal force according to the rotation speed, and the frictional force between the substrate and the washing liquid, the washing liquid spreads over the entire surface of the substrate and the substrate is extracted by centrifugal force. The edge, rather than flowing down the side surface at the edge of the substrate. In this way, by controlling the amount of the washing liquid, the washing liquid can be prevented from contacting the side surface and the bottom of the substrate, and thus damage caused by the washing liquid can be prevented from occurring in the lower layer of the substrate.

In addition, in order to prevent the washing liquid from flowing down along the side surface of the substrate, the wet cleaning module 300 may further include an auxiliary inert gas sprayer (not shown) that supplies the inert gas to the side surface of the substrate. When the substrate is cleaned, by supplying an inert gas to the side surface of the substrate, the washing liquid can be prevented from being along The side surface of the substrate flows down.

In this case, by spraying the inert gas from the lower portion of the edge of the substrate to the upper portion thereof, the centrifugal force does not prevent the washing liquid from spreading across the entire top surface of the substrate, and in addition, the lotion can be effectively prevented. Flows down the side surface of the substrate.

The load lock module 400 changes the pressure between the vacuum state and the atmospheric state, and a cassette (not shown) for accommodating the substrate is prepared inside the load lock module 400.

The vacuum transfer module 500 transfers the substrate to the dry cleaning module 600 under vacuum, and the vacuum transfer module 500 is coupled to the load lock module 400. The inside of the vacuum transfer module 500 is maintained in a vacuum state. Further, a transfer robot 510 for transferring a substrate is prepared inside the vacuum transfer module 500. Herein, the transfer robot 510 may be a dual type transfer robot including two transfer arms to improve transfer efficiency.

The dry cleaning module 600 cleans (or etches) the substrate during the dry cleaning process. In this embodiment, four dry cleaning modules are provided. The four dry cleaning modules are placed along the perimeter of the vacuum transfer module 500. Referring to FIG. 5, the dry cleaning module 600 includes a chamber 610 that is coupled to the vacuum transfer module 500. The pedestal 620 on which the substrate W is placed is disposed in a vertically movable manner at the lower side of the space inside the chamber. The pedestal 620 can include a heat exchanger to adjust the temperature of the substrate. A shower head 630 for spraying a cleaning gas is disposed at an upper side in the inner space of the chamber 610, so that the ruthenium oxide layer and other impurities formed on the substrate W can be cleaned by a dry cleaning process.

A sprinkler head 630 is coupled to the gas supply system 640 for introducing a flux controlled purge gas. In the dry cleaning, the HF gas is not used alone, and a mixed gas including at least the HF gas is used as the cleaning gas. For example, a mixed gas of HF gas and NH ₃ gas can be used as the cleaning gas. Each component gas of the purge gas is supplied to the gas supply system 640, respectively, such that until the component gases are supplied to the chamber, the component gases are mixed. That is, although not subdivided and not shown, the gas supply system 640 includes a gas supply passage 642 connected to a supply source 641 (a tank containing a gas bomb or a fluid) of each component gas; A mass flow controller (MFC) 643 is included in the supply source 641.

The showerhead 630 is a member for spraying component gases that is received from the gas supply system 640 into the chamber 610. In order to effectively maintain and clean the showerhead 630, the showerhead 630 may be of a non-mixed type in which the purge gas does not mix inside the showerhead 630, but rather after it is sprayed into the chamber 610. To this end, a dual type sprinkler head 630 can be applied, wherein at least two separate flow paths are formed inside the sprinkler head 630. The means for spraying the purge gas into the chamber 610 may be a different type of member than the showerhead (such as a gas nozzle or gas spray plate), or each of which may be from the lower portion of the chamber 610 (rather than A type of component introduced in the upper part).

Further, a halogen lamp for heating the substrate may be additionally disposed at an upper end portion of the chamber 610.

Next, the dry cleaning process will be described. The pressure inside the chamber 610 is adjusted to 10 mTorr to 150 Torr, and the temperature of the susceptor 620 is adjusted to Celsius. 20 degrees to 70 degrees Celsius, and then the substrate W is loaded. The temperature of the susceptor 620 is selected within the range of the cleaning reaction most suitable for the cleaning gas, and the temperature of the susceptor 620 becomes the temperature of the substrate W. At this time, in order to prevent condensation of the cleaning gas, the wall of the chamber 610 may be maintained at 50 degrees Celsius to 150 degrees Celsius, and the shower head 630 is also maintained at 50 degrees Celsius to 150 degrees Celsius.

Next, flux-controlled HF gas is introduced into the chamber 610 from the HF gas supply system, and at the same time, flux-controlled NH ₃ gas is introduced into the chamber 610 from the NH ₃ gas supply system.

In this manner, the HF gas and the NH ₃ gas that have been introduced into the chamber 610, respectively, are sprayed into the chamber 610 via the shower head 630, and the HF gas and the NH ₃ gas are mixed. Therefore, the ruthenium oxide layer and other impurities formed on the substrate W are etched by the mixed gas. Subsequently, the susceptor 620 is lifted to a position illustrated by a broken line in FIG. 5, and the etching by-product is removed by heating the substrate W with a halogen lamp at 80 degrees Celsius to 200 degrees Celsius.

The cleaning gas can be used as a carrier gas by adding at least one inert gas selected from N ₂ , Ar, and He to the cleaning gas. Further, a cleaning gas to which an IPA gas is added can be supplied. In this case, since the IPA is a fluid at room temperature, the IPA can be vaporized by a suitable foaming or vaporizer, and then the IPA is introduced.

Hereinafter, a substrate processing operation using the substrate processing system described above will be described.

FIG. 6 is a flow chart of a substrate processing method M100 according to an embodiment of the present invention.

Referring to FIG. 6, the substrate to be processed is placed in the cassette module 100. In this case, as described above in the prior art, an etching gas including a halogen component such as F, Cl, or Br may be used to etch the substrate, and thus the substrate becomes a substrate in which the pattern is formed. The substrate is transferred to the wet cleaning module 300 via the atmospheric transfer module 200 and the buffering member 220, and the preliminary wet cleaning process S10 is performed in the wet cleaning module 300.

Next, the preliminary wet cleaning process S10 will be described. First, in operation S11, by supplying a washing liquid (for example, ozone water) while rotating the substrate, the washing liquid is spread throughout the entire surface of the substrate to remove any organic material remaining on the substrate. The substrate is rinsed by supplying ultrapure water (rinsing solution) to the substrate, and then the substrate is dried in operation S12, thereby completing the preliminary wet cleaning process. Next, in the process S20, the substrate is transferred to the dry cleaning module 600 via the buffer component 220, the load lock module 400, and the vacuum transfer module 500, and the dry cleaning process S30 is performed in the dry cleaning module 600.

Next, the dry cleaning process S30 will be described. In the case where the substrate temperature is maintained within a temperature range most suitable for the cleaning reaction (20 degrees Celsius to 70 degrees Celsius), the ruthenium oxide layer is sprayed onto the substrate by spraying the cleaning gas (HF, NH ₃ ) to the substrate in operation S31. Other impurities are etched by reacting with the cleaning gas. Subsequently, the susceptor 320 is lifted, and the etching by-product is removed by heating the substrate at 80 degrees Celsius to 200 degrees Celsius in operation S32.

Subsequently, in the process S40, the substrate is again transferred to the wet cleaning module 300, and the wet cleaning process S50 is performed in the wet cleaning module 300. The wet cleaning process S50 removes fumes from the substrate. As described above in the prior art, when halogen components such as F, Cl, and Br are added (in the etching process, the halogen components are added to the etching gas to form a pattern on the substrate) The halogen component reacts with moisture in the atmosphere to form a solid hydrate when the substrate is inside the trench 40 and then exposed to the atmosphere.

Next, the wet cleaning process S50 will be described. In operation S51, by supplying the washing liquid (ultra-pure water) while rotating the substrate, the washing liquid is spread over the entire surface of the substrate, and the flue gas is removed by reacting with the washing liquid. Next, the wet cleaning process S50 is completed by drying the substrate in operation S52.

At the time of the process after the wet cleaning process S50, it is sometimes necessary to form a chemical oxide on the substrate for the stability of the process. In this case, the flue gas is removed, and then a chemical oxide is formed on the substrate by supplying a washing liquid such as ozone water or ammonia water (which promotes formation of a chemical oxide) to the substrate (then, a flushing process can be performed), And then the substrate is dried.

Subsequently, in the process S60, when the substrate has been transferred from the wet cleaning device to the cassette module 100, the entire cleaning process of the substrate is completed, and the substrate is proceeded to the subsequent process.

In the embodiments described above, most of the ruthenium oxide layer and other impurities on the substrate are removed by a dry cleaning process. Therefore, as in a typical wet cleaning process, the underlying layer (such as SOD or BPSG) can be prevented from being damaged.

In the wet cleaning process, the substrate is not completely etched (i.e., the lotion reacts only with the flue gas and does not react with other portions), and the flue gas on the substrate is selectively removed. Unlike conventional techniques, this prevents the underlying layer from being damaged by isotropic etching. In this case, as described above, by appropriately adjusting the supply of the washing liquid, it is possible to prevent the washing liquid from flowing down along the side surface and flowing down the bottom of the substrate, thereby preventing the lower layer from being damaged.

That is, in this embodiment, the substrate is etched by a dry cleaning process, and The flue gas is removed during the wet wash process. Therefore, the under layer is prevented from being damaged, and in addition, the ruthenium oxide layer, the etching by-product, and the flue gas can be effectively removed from the substrate.

When an organic material is present on the substrate, the organic material may not be effectively removed in the dry cleaning process. That is, the organic material and the ruthenium oxide layer may remain on the substrate even after the dry cleaning process. However, in this embodiment, any organic material on the substrate can be removed by a preliminary wet cleaning process prior to performing the dry cleaning process to more thoroughly clean the substrate.

FIG. 7 is a flow chart of a substrate processing method M200 according to another embodiment of the present invention.

Referring to FIG. 7, in the present embodiment, the dry cleaning process S110 is directly performed without performing the preliminary wet cleaning process, and then the substrate transfer process S120, the wet wash process S130, and the substrate unload process S140 are sequentially performed. In contrast to the embodiments described above, according to the present embodiment, the preliminary wet cleaning process is not performed in order to reduce the total cleaning time taken. Therefore, the substrate processing method M200 can improve the efficiency of the substrate processing method M100 when a separate wet cleaning process is not required before the dry cleaning process (for example, when all foreign matter is dissolved by the cleaning gas on the substrate).

While the invention has been described with respect to the preferred embodiments of the embodiments of the invention More specifically, it is possible to make various changes and modifications in the configuration of the component parts and/or target combination configurations within the scope of the invention, the drawings and the scope of the appended claims.

10‧‧‧Semiconductor substrate

20‧‧‧ liner oxide pattern

30‧‧‧ nitride pattern

40‧‧‧ Ditch

50‧‧‧Fume

100‧‧‧ cassette module

200‧‧‧Atmospheric Transfer Module

210‧‧‧Transfer manipulator

220‧‧‧buffer parts

230‧‧‧Auxiliary transfer robot

300‧‧‧Wet wash module

310‧‧‧ chamber

320‧‧‧Base

330‧‧‧Washing sprayer

400‧‧‧Load lock module

500‧‧‧Vacuum Transmission Module

510‧‧‧Transfer manipulator

600‧‧‧ dry cleaning module

610‧‧‧室

620‧‧‧Base

630‧‧‧ sprinkler head

640‧‧‧ gas supply system

641‧‧‧Supply source

642‧‧‧ gas supply path

643‧‧‧Quality Flow Controller (MFC)

1000‧‧‧Substrate processing system

M100, M200‧‧‧ substrate processing method

S10‧‧‧ Initial wet cleaning process

S11, S12, S31, S32, S51, S52‧‧‧ operations

S20, S40, S60‧‧‧ Process

S30, S110‧‧‧ dry cleaning process

S50, S130‧‧‧ Wet washing process

S120‧‧‧Substrate transfer process

S140‧‧‧Substrate unloading process

W‧‧‧Substrate

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view showing a method of forming a typical isolation layer.

2 is a plan view schematically showing a state in which a trench is formed in a semiconductor substrate by an etching device. When the semiconductor substrate is transferred to a dry cleaning device, the semiconductor substrate is exposed to the atmosphere, and thus smoke is generated inside the trench.

3 is a schematic configuration diagram of a substrate processing system in accordance with an embodiment of the present invention.

4 is a schematic configuration diagram of the wet cleaning module of FIG. 3.

Figure 5 is a schematic configuration diagram of the dry cleaning module of Figure 3.

6 is a flow chart of a substrate processing method in accordance with an embodiment of the present invention.

7 is a flow chart of a substrate processing method in accordance with another embodiment of the present invention.

100‧‧‧ cassette module

200‧‧‧Atmospheric Transfer Module

210‧‧‧Transfer manipulator

220‧‧‧buffer parts

230‧‧‧Auxiliary transfer robot

300‧‧‧Wet wash module

400‧‧‧Load lock module

500‧‧‧Vacuum Transmission Module

510‧‧‧Transfer manipulator

600‧‧‧ dry cleaning module

1000‧‧‧Substrate processing system

Claims (5)

A substrate processing method comprising: performing a dry cleaning process, spraying a cleaning gas containing HF gas onto a substrate to remove a ruthenium oxide layer formed on the substrate; performing a wet cleaning process, supplying a washing liquid to the substrate to clean the chamber Determining the surface of the substrate, and drying the substrate; and performing a preliminary wet cleaning process, supplying a washing liquid to the substrate to clean the surface of the substrate, and drying the substrate before the dry cleaning process. The substrate processing method of claim 1, wherein the preliminary wet cleaning process comprises removing organic material from the surface of the substrate, and the wet cleaning process comprises removing smoke, The flue gas is produced from an etching gas residue containing a halogen compound. The substrate processing method according to claim 1, wherein in the wet cleaning process, the washing liquid is supplied to a top surface of the substrate when the substrate is rotated, and according to the substrate The centrifugal force generated by the rotation adjusts the supply amount of the washing liquid to prevent the washing liquid supplied to the top surface of the substrate from flowing down along the side surface of the substrate. The substrate processing method of claim 1, wherein the wet cleaning process comprises spraying an inert gas to a side surface of the substrate to prevent the washing liquid supplied to a top surface of the substrate from being along The side surface of the substrate flows down. The substrate processing method according to claim 4, wherein The inert gas is sprayed from a lower portion of the edge of the substrate to an upper portion thereof.