JP2908277B2 - Method and apparatus for chemical processing of substrates - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for chemical treatment of a substrate by sequentially performing a chemical treatment, a cleaning process and a drying process on at least one substrate, and an apparatus for the chemical treatment.

[0002]

2. Description of the Related Art Automatic wet worktables (automa)
Tischche Nassbank) has a series of tanks or tanks for a series of chemical wet treatments. After a series of chemical treatments, the substrate, for example a silicon wafer, is submerged in a separate washing or washing bath and subsequently dried.

Drying of the substrate can be effected, for example, by means of a centrifuge, but also during the slow discharge of the substrate from the washing bath.

From EP-A-385 536, a so-called "Marangoni dryer"
ni-Trockner ")" is known. In the case of the method described in this EP, in addition to the slow discharge of the substrate from the bath, steam is used on the substrate, in which case the vapor does not condense on the substrate, but Diffuses in liquids. In the liquid meniscus on the substrate surface, a concentration gradient and thus a surface tension gradient are generated. This gradient causes a movement of the liquid from the substrate into the liquid (Marangoni effect) and an excellent drying of the substrate.

From US Pat. No. 4,742,752,
Devices and methods for cleaning and drying wafers are known, where the wafers are in a cassette. The wafers are separated from the cassette and slowly drained from the cleaning bath, and subsequently placed in a similarly slowly drained and dried cassette.

The above-mentioned apparatus or method has the following disadvantages: the cleaning bath is in any case a separate bath from the other processing baths and is used exclusively for cleaning substrates.
However, the inherent washing bath means an increased demand for space or space. In addition, the substrate must pass through the surface of the fluid for chemical treatment into the air before the cleaning step and then re-enter the cleaning liquid afterwards, as is well known. Adverse consequences for particulate foreign matter on the substrate can result. This applies in particular to hydrophobic surfaces (for example by HF treatment). Similarly, the loading or unloading of substrates into and out of different vessels for chemical processing or cleaning steps means an increased waste of time. Similarly, in known devices or methods, a cassette (carrier) for handling substrates is always required.

From US Pat. No. 5,275,184,
The wafer holding mechanism (Wafe) during the fluid processing process in the processing chamber using the reduced pressure and during the drying process
Equipment for processing wafers present in r-Anhebmechanismus is known. Accordingly, the disadvantages described above for U.S. Pat. No. 4,742,752 also apply here, since the wafer is present in the wafer holding mechanism during the drying process and is therefore optimally dried. Because there is no.
Also, in this case, the drying process proceeds slowly, since the holding device, in addition to the wafer, must or must be dried. Therefore, processing without a cassette on the substrate during the drying process is not possible.

[0008]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to streamline the process flow in an automatic wet worktable.
It is an object of the present invention to provide a method and / or an apparatus for a chemical wet process which saves the necessary time and space. It is another object of the present invention to maintain as little foreign matter on the substrate during such a flow of the chemical wet process. Finally, another object of the present invention is to make it possible to obviate the need for cassettes or the like relating to the loading or unloading of substrates into or out of the bath, for holding substrates. .

[0009]

The object is achieved according to the invention by the features of claim 1. Therefore, a cassette or the like is not required.

[0010]

Advantageously, the chemical treatment and the cleaning process in the same tank are replenished or (partially) exchanged for the chemical treatment fluid by another such fluid and / or exchanged with a cleaning liquid. It is implemented by. Advantageously, in the case of a continuous chemical process, a cleaning liquid is first introduced and one or more substrates are discharged from the bath before the exchange of the fluid for chemical treatment with another such fluid, And at this time, it is dried at the same time. Subsequently, the cleaning liquid is exchanged for another fluid for chemical treatment, and the substrate is put back into the bath.

In the case of the present invention, the drying step is performed while the substrate is separated from the cleaning liquid. In the case of the drying process, the substrate is usually discharged from the cleaning liquid very slowly.

In order to effectively carry out the above process, steam is advantageously used on the substrate, which vapor does not condense on the substrate and mixes with the cleaning liquid. Advantageously, the mixture has a lower surface tension than the cleaning liquid, which means that there is a force to push the cleaning liquid adhering to the substrate back into the bath.

The exchange of the cleaning fluid with the fluid for the chemical treatment takes place in a preferred embodiment by displacement. For example, the derivation of a fluid for chemical processing and the subsequent supply of a cleaning liquid exposes the substrate to increasing particulate contaminants in the air. Eliminating the fluid with another fluid, such as a cleaning liquid, has the advantage that the substrate does not need to penetrate the phase boundaries and is not exposed to air. Of course, several types of fluids for chemical treatment can also be interchanged by flushing before the cleaning process. The exchange, in particular with regard to the exchange of a fluid for a chemical treatment with another such fluid, may include a partial exchange, i.e. mixing.

Advantageously, the cleaning liquid is introduced into the bath, and at the same time a mixture of the fluid for the chemical treatment and the cleaning liquid is withdrawn.

The introduction of the cleaning liquid and the withdrawal of the fluid for the chemical treatment preferably take place at different locations in the tank. This, for example, optimizes the exchange of the fluid for another fluid over time.

The introduction of the washing liquid takes place preferably from the bottom of the tank, while the discharge of the mixture takes place by overflow. Therefore, no additional pumping device is required for this derivation. By being introduced from the bottom of the tank, i.e., away from the outlet position, the smallest possible amount of the introduced washing liquid is derived. This is likewise advantageous with respect to gravity, possibly with increasing temperature gradients. This is economically advantageous and saves time.

In a preferred embodiment of the invention, the fluid for the chemical treatment is diluted hydrofluoric acid. Treatment in diluted hydrofluoric acid (HF) is effective in removing the oxide layer on the substrate surface and in obtaining a hydrogen passivated hydrophobic surface that is required for some of the continuous steps. .

In another advantageous embodiment of the invention,
The fluid for the chemical treatment is ozone. The treatment with ozone is carried out, for example, if it is intended to grow the chemical oxide again on the (hydrophobic) substrate surface treated with HF for cleaning reasons and thus to obtain a hydrophilic surface. Is done.

Advantageously, in the case of the method of loading and / or unloading at least one substrate into and out of the bath, the substrate is held in the bath by a receiving device and loaded and / or unloaded.

An advantage of the present invention is that a cassette as a support device for substrates and / or a cassette for loading or unloading substrates can be dispensed with. The method according to the invention can therefore be performed without a carrier. This avoids the known disadvantages of the carrier with respect to the drying step (contact points between the carrier and the substrate do not dry). The receiving device according to the invention is not a carrier but merely a support device capable of loading and unloading one or more substrates. Carrier-free drying not only omits the carrier drying step, but also reduces the cleaning time and even the amount of cleaning liquid used for the cleaning process. Similarly, chemical fouling in the drying equipment is reduced by the carrierless treatment method.

[0021] Advantageously, the receiving device comprises a support device which is divided into two parts and a knife which is vertically movable separately.

Advantageously, the receiving device discharges the substrate from the bath until the substrate is guided or held by a guide provided on the opposite surface inside the hood.

In a preferred embodiment, a movable holder is provided for holding the substrate dry on the tank at the position of the substrate after the substrate has been ejected from the tank. The movable holder under or in the hood is designed such that when the substrate is held by the movable holder, the hood can be easily opened and closed without changing the position of the substrate. I have. The movable holder is always dry and only contacts the already dried substrate.

Advantageously, the method according to the invention is provided with auxiliary means for the ultrasonic or megasonic cleaning and / or cleaning steps. To this end, the bath is advantageously provided with a piezoelectric element for generating sound waves for cleaning the substrate. In this regard, such a "megasonic" system is advantageous because particulate matter on the substrate is reduced to a minimum with the method according to the invention. Thus, a very thorough cleaning of the substrate is achieved.

The above-mentioned object is likewise achieved according to the invention by the features of claim 18.

Advantageously, an outer tank is additionally provided outside the (inner) tank, which outer tank is used, for example, as a safety tank.

A leveling screw is advantageously provided for the adjustment of the inner bath with respect to a uniform overflow of the fluid to be exchanged.

A diffuser is preferably provided as an introduction device, preferably at the bottom of the vessel. This diffuser is important for the above-mentioned ozone (O ₃ ), for example.

In the case of liquids, for example diluted hydrofluoric acid, pumps which are likewise advantageously combined with an introduction mechanism at the bottom of the tank are also advantageous.

In the case of the device according to the invention, the tank or the dried substrate is protected from foreign particles and
A hood is present on the tank to allow for a rich steam atmosphere in the area above the tank. The hood for the introduction of steam
Incorporated diffuser, i.e., the perforated diffuser incorporated into the hood, IPA (isopropyl alcohol) / N 2 _- has for the supply or dispersion mixing. In this way, a homogeneous and uniform vapor atmosphere is created in the processing chamber for all substrates, so that the processing conditions for each wafer are the same. Mixing of IPA and nitrogen is performed in a gas scrubbing bottle (bubbler).

The substrate is preferably held in a bath by a receiving device, which comprises a knife-shaped element, a so-called knife and, for example, two support devices. The knife and the support device are each movable relative to one another, and the knife is preferably arranged between the two support devices. The support device is provided in a bath, while the knife can also float from the liquid.

In the case of the present invention, the hood on the bath has a guide for the substrate. This guide is advantageously fixed to two opposing faces inside the hood. In this guide, a substrate, for example a silicon wafer, can be guided or held.

The guides are fixed to opposing surfaces of the hood. The guide has a groove shape for receiving a plurality of substrates. This eliminates the need for a cassette for holding substrates.

The guide in the hood is preferably implemented in two parts, in which case at least one edge of these receiving devices is inclined in order to facilitate the receipt of the substrate.

[0035] Advantageously, at least one of the guides has beveled edges to facilitate receipt of the substrate. This also facilitates opening and closing of the hood.

In a preferred embodiment of the invention, a movable holder is provided, which can enter the tank from outside, under the hood and on the tank, And it has a bow-shaped recess. This movable holder can hold a substrate alone, as well as a storage device in a hood and also a combination of a knife in a tank and two support devices. The substrate rests on the arcuate recess of the movable holder, and the substrate is fixed in the hood by the receiving device, so that the hood can be opened without entrainment of the substrate. Further, the substrate is held only by the movable holder until the system handler removes the substrate from the movable holder for further processing.

The invention and further developments and advantages of the invention will now be described in more detail with reference to an embodiment shown in the drawings.

[0038]

1 shows an apparatus (1) for the chemical wet processing of a substrate, in particular a wafer (2). The device (1) has an outer tank (5) and an inner tank (10).
The outer tub (5) has an outer annular chamber (6) and an inner annular chamber (7). The inner tank (1) is placed on the inner tank (10).
A hood (12) with an opening mechanism (13) for uncovering 0) is arranged. Food (12)
Has a space partitioned by the diffusion plate (14), in the space for example IPA / N 2 _- can be introduced into the mixture. The inner tank (10) is a narrow cylinder (18)
At the lower end of the inner tank (10). Due to the frustoconical intermediate part (20), the diameter of the inner vessel (10) is enlarged to a wide cylinder (19). At the upper edge of the inner tub (10), the edge is formed as an inclined outer edge (23). This improves the properties of the upper edge of the inner bath (10) with respect to liquid overflow. By means of leveling screws (4) which fix the inner tub (10) to the outer tub (5) and are arranged in the chamber (6) of the outer tub, the inner tub (10) can for example It can be adjusted to ensure a uniform overflow of the washing solution over it. The inner tank (10) has its bottom (1
It has two introduction devices arranged one above the other, namely a diffuser (25) and an introduction mechanism (26). The diffuser (25) is located above the introduction mechanism (26). Diffuser (25)
Is connected to a fluid reservoir (35) via conduit (30), it is advantageously ozone (O ₃₎ is placed in the fluid reservoir. In the case of FIG. 1, the direction of the flow of ozone is indicated by arrows. The introduction mechanism (26)
It is connected to a pump (36) via a conduit (31). A pump (36) optionally comprises a fluid for chemical processing for the wafer (2), for example diluted hydrogen fluoride, from a fluid tank (37) or (38) via a conduit (39) or (40). Pump the acid. In the case of FIG. 1, the arrows indicate the direction of flow of the pumped fluid in the conduit (31). Similarly, the inner tank (1
0) during which the right and left support devices (43) or (44)
These support devices are fixed to two holders (46) or (47), which can be adjusted in parallel in height in the inner tank (10). The right and left support devices (43, 44) have an arcuate cutting (60) or (61) for receiving the wafer (2). Between the two support devices (43, 44) there is a so-called knife (42), an elongated element with a sharp end. The knife (42) is made, for example, of quartz glass and has a right and left support device (4).
It is movable in height regardless of 3) or (44). In the case of FIG. 1, the knife (42) is connected to the wafer (2).
Is lifted out of the inner tank (10) and the wafer (2) is shown held in the hood (12) above the inner tank (10) by the holder (51). The guide or wafer storage device (51), like the support devices (43, 44), has a groove-like shape for handling a large number of wafers simultaneously without a cassette. The inner edge of the guide (51) is beveled to facilitate the entry of the wafer (2) into the guide (51). One or more wafers (2) are held or guided by a guide (51). The outer tub (5) is closed at the top by a cover (8) having an opening (9). The outer tank (5) used as a safety tank is a narrow cylinder (48) which is connected to a wide cylinder (49) via an intermediate part (50) formed as a disk with a circular opening in the center. It is composed of Wide cylinder (49)
Is the outer surface of the inner annular chamber (7) or the outer annular chamber (6)
The overflowed fluid can be led out or pumped out from the outer annular chamber through the opening (9).

FIG. 2 shows the first stage of the process flow shown in FIGS. FIG. 2 shows a wafer packet, represented by wafer (2), being supplied to the apparatus by a system handler (90). The hood (12) to which the wafer storage device (51) is connected is opened by an automatic cylinder (15). Knife (42) and right and left support devices (43) or (44)
Is ready to receive the wafer (2). Moreover, the knife (42) is slightly submerged below the support device (43, 44), so that the tip of the knife (42) is located on the circumference of the arcuate cutting (60) or (61), The wafer (2) is placed on the circumference later.

FIG. 3 shows the lowering of the wafer (2) into the inner bath (10), which is filled, for example, with HF.

In FIG. 4, the hood (12) has an inner tank (1).
0) and is immersed in a lower position where the wafer (2) almost reaches the middle part (20) in the inner bath (10), in which case The knife (42) and the right and left support devices (43) or (44) move down at the same speed.

FIG. 5 shows the drying stage of the wafer (2), ie the lifting of the wafer (2) from the inner bath (10). According to the invention, the chemical fluid HF is exchanged with another fluid between the process steps shown in FIG. 4 and the process step shown in FIG. 5, in which case the cleaning liquid is advantageously introduced last. . Advantageously, on the inner bath (10), steam is used for the wafer, which vapor does not condense on the wafer (2) and in this case the mixture of cleaning liquid and vapor has a lower surface tension than the cleaning liquid alone Having. For this purpose, the hood (12) is still closed. Advantageously, the knife (42) moves up at a constant speed, but the two support devices (43) and (44) move up only at half speed, so that these support devices are left behind. .

FIG. 6 shows the supporting devices (43) and (44).
Is shown stopped; further lifting of the wafer (2) is performed only by the knife (42). It is shown that the wafer (2) is still in contact with the cleaning liquid in the inner bath (10) before the sole lifting by the knife (42).

FIG. 7 shows the end of the drying stage, ie the wafer (2) has been lifted completely out of the inner bath (10) and has a knife (42) and a holder (51). Is held by

In FIG. 8, before the hood (12) is opened, the movable holders (70) and (71) move the wafer (2) at the position of the wafer during or after the hood (12) is opened. That is, it is shown entering into the space above the inner tub (10) to hold it from below during or after the holder (51) is removed. The holding of the wafer (2) can only be carried out by means of the movable holders (70) and (71), ie the knife (42),
Support device (43, 44) and wafer storage device (51)
Is not required for further holding of the wafer (2). The movable holder (70) 71) has an arc-shaped notch to hold the wafer (2) in that position. Similarly, in FIG. 8, the knife (42) is again in the inner tub (10),
That is, it is shown submerged in the initial position of the knife below the right and left support devices (43) and (44) (see FIG. 2).

Next, in FIG. 9, the hood (12) is opened and the system handler (90) has removed the wafer (2) from the apparatus (1) for further processing. 2 to 9 show one work cycle process.

The invention has been described in detail with reference to advantageous embodiments. However, those skilled in the art can make numerous modifications or developments without departing from the inventive concept.

[Brief description of the drawings]

FIG. 1 is a sectional view of an apparatus according to the present invention.

FIG. 2 shows the first stage of the process flow according to the invention.

FIG. 3 shows a second stage of the process flow according to the invention.

FIG. 4 is a diagram showing a third stage of the process flow according to the present invention.

FIG. 5 shows a fourth stage of the process flow according to the invention.

FIG. 6 illustrates a fifth step in the process flow according to the present invention.

FIG. 7 illustrates a sixth step in the process flow according to the present invention.

FIG. 8 illustrates a seventh step in the process flow according to the present invention.

FIG. 9 is a diagram showing an eighth stage of the process flow according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Device for chemical treatment of substrate 2 Substrate 7 Derivation device for fluid from tank 10 Tank 12 Hood 23 Overflow device 25 Diffuser 26 Introducing mechanism 30, 31, 35, 37, 38, 39, 40 Introducing device 36 Pump 42 Knife 43,44 Supporting device 51 Guide 52 Inclined edge 70,71 Movable holder

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification code FI B08B 3/08 B08B 3/08 A C23G 1/00 C23G 1/00 5/02 5/02 H01L 21/306 H01L 21/306 Z (72) Inventor Milan Kozak Hufingen Hohenstraße, Germany 36 (72) Inventor Johann Dürst, Germany Donaueschingen Schwalbenweg 15 (56) References JP-A-58-87826 (JP, A) JP-A-5-23648 (JP, A) JP-A-1-135024 (JP, A) JP-A-64-32645 (JP, A) JP-A-2-50426 (JP, A) JP-A-3-188631 (JP, A) JP-A-2-90524 (JP, A) JP-A-1-140631 (JP, A) JP-A-6-9300 (JP, A) JP-A-1-118339 (JP, U) Japanese Utility Model 4-15232 (JP, U) Japanese public utility model 48-31886 (JP, Y1)

Claims (26)

(57) [Claims] 1. A method for chemically treating a substrate (2) by sequentially performing a chemical treatment, a cleaning process and a drying process on at least one substrate (2), wherein the chemical treatment and the cleaning process are performed in the same tank (10). The drying process in a tank (1
0) and by holding the substrate (2) in the guide (51) of the hood (12) when lifting the substrate (2) from the bath (10). Method for chemical treatment of substrates. 2. The method according to claim 1 , wherein the cleaning solution is introduced after the chemical treatment.
Expel fluid for chemical treatment in the tank (10) I,
The method of claim 1, wherein the fluid for the chemical treatment is exchanged for a cleaning liquid. 3. The drying process is performed by using steam,
3. The method according to claim 1, wherein the vapor does not condense on the substrate and diffuses into the cleaning liquid. 4. The method of claim 3 , wherein the mixture of vapor and cleaning liquid has a lower surface tension than the cleaning liquid. 5. A cleaning liquid is introduced into the tank (10) and at the same time a mixture of a fluid for chemical treatment or a mixture of a fluid for chemical treatment and a cleaning liquid is derived.
A method according to any one of claims 1 to 4 . 6. A tank (10) for introducing another fluid or a cleaning liquid for chemical treatment and for deriving a fluid for chemical treatment.
6. The method according to claim 5 , wherein the method is performed at different positions. 7. The method according to claim 5 , wherein the introduction of another fluid or cleaning liquid for the chemical treatment takes place from the bottom of the tank.
6. The method according to 6 . 8. A mixture comprising a fluid for chemical treatment.
Stone is performed by an overflow derivation of mixed compound made of the fluid and the cleaning solution for the chemical treatment, the claims 5 7
The method according to any one of the preceding claims. 9. is a hydrofluoric acid fluid was diluted for chemical treatment method according to any one of claims 1 to 8. 10. is a fluid ozone for chemical treatment method according to any one of claims 1 to 8. 11. A storage device (42, 43, 4) capable of loading and / or unloading a substrate (2) in a tank (10).
The method according to any one of claims 1 to 10 , wherein the method is carried out according to 4). 12. The method according to claim 11 , wherein the receiving device has a knife (42) and a supporting device (43, 44). 13. A knife (42) and a support device (43).
44) is a substrate, and the substrate is a guide (5) of the hood (12).
Discharging from the tank until retained by 1).
13. The method according to 11 or 12 . 14. movable holder (70, 71) is held at the position of the substrate to be and substrate movable under the substrate upon discharge of the substrate (2), one of the Claims 1 to 13 Item 2. The method according to item 1. To aid 15. The cleaning process by treatment with megasonic or any of claims 1 to 14 1
The method described in the section. 16. A device for carrying out the method according to any one of claims 1 to 15 (1), - a fluid or cleaning fluid for the chemical treatment of the vessel (10) <br / > Introduction device for (25, 30, 31, 35, 36, 3
7,38,39,40); - All derivation of the fluid for chemical treatment of the vessel (10)
Because the overflow equipment (23); - receiving device for the substrate (2) (42,43,4
4); - Food (12 above the vessel (10)) and - characterized in that it comprises a substrate (food for retention of 2) (12) of the guide (51), the chemical substrate Equipment for processing. 17. The method according to claim 16 , wherein an outer tub is provided.
The described device (1). 18. The device (1) according to claim 16 or 17 , wherein the device has leveling screws for adjusting the bath. 19. An introduction device (25, 30, 31, 35,
36, 37, 38, 39, and 40) are diffusers (2
Device (1) according to any one of claims 16 to 18 , comprising (5). 20. An introduction device (25, 30, 31, 35,
36, 37, 38, 49, 40) comprises a pump (36) having an introduction mechanism (26).
Device (1) according to any one of items 16 to 19 . 21. A storage device for a substrate (2).
43, 44) are the knife (42) and the supporting device (43, 4).
Device (1) according to any one of claims 16 to 20 , comprising (4). 22. Guide (51) is held at the side surface of which and the substrate (2) is divided into two parts at the position of the substrate, according to any one of claims 16 to 21 ( 1). 23. At least one of the guide (51) has the edge (52) inclined, claims 16 22
Device (1) according to any one of the preceding claims. 24. A movable holder (70, 71) for a substrate (2) is provided on the tank (10), and the movable holder is placed under the substrate (2) after discharging the substrate (2). Device (1) according to any one of claims 16 to 23 , which is movable. 25. The device (1) according to any one of claims 16 to 24 , wherein a device for processing with megasonics is provided. 26. A steam processing device is disposed on the tank (10).
The method according to any one of claims 16 to 25, wherein
The described device (1).