JP2596212B2 - Wet processing equipment for semiconductor devices - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a wet processing apparatus in a semiconductor device manufacturing process.

The wet processing in the semiconductor device manufacturing process includes the following: a) Removal of unnecessary coatings (resist, SiO ₂ film) used in the semiconductor manufacturing process.

B) Removal of metal salts, organic substances, and other contaminants that degrade the characteristics of the device.

C) Etching during pattern formation.

Etc.

[Conventional technology]

4 and 5 show an example of this type of conventional wet processing apparatus. FIGS. 4 (a) to 4 (c) show conventional processing tanks, of which FIG. FIG. 4B is a side view, and FIG. 4C is a top view.

In FIG. 4, 1 is a wafer cleaning tank, 2 is a wafer to be cleaned, 3 is a wafer cassette for storing the wafer 2,
Reference numeral 4 denotes a filter, reference numeral 5 denotes a chemical liquid circulation pump, reference numeral 6 denotes a rectifying plate which also serves as a bottom plate on which the wafer cassette 3 is installed, and which maintains a liquid flow in a laminar flow state, and reference numeral 1b denotes an overflow receiving tank. Of these processing tanks, wafer cleaning tank 1, wafer cassette 3, filter
4. All parts that come into contact with the chemical solution, including the current plate 6, are made of fluororesin or coated with fluororesin so as not to be immersed in the chemical solution.

 Next, the operation will be described.

The wafer cleaning tank 1 is filled with a chemical solution, and the wafer 2 stored in the wafer cassette 3 is immersed in the chemical solution. As a result, the surface of the wafer 2 is eroded by the chemical solution, thereby removing harmful substances and foreign substances or forming a circuit pattern. At this time, various coating pieces and foreign substances adhering to the surface of the wafer 2 move into the chemical solution. Therefore, when this chemical solution is circulated and the wafer 2 is repeatedly washed, coating pieces and foreign substances (hereinafter, collectively referred to as “dust” in a sense of a substance which is not preferable for the wafer) existing in the chemical solution are again generated. It will adhere to the wafer 2 and create significant defects in the product. Therefore, conventionally, in such a cleaning tank, an operation of continuously guiding the chemical liquid to the outside of the tank by the chemical liquid circulating pump 5 and passing the same through the filter 4 to remove dust, and then returning to the wafer cleaning tank 1 is performed. Have been. As a result, the concentration of dust in the wafer cleaning tank 1 is kept low, thereby preventing dust from adhering to the wafer 2 in the wafer cleaning process.

FIG. 5 shows an automated apparatus in which these processing layers are arranged in a draft according to the process. 5 (a) is a front view, FIG. 5 (b) is a top view, and FIG. 5 (c).
Is a side view. In FIG. 5, the tanks 14, 15, and 16 are the tanks in FIG. 4, which are an HF solution tank, a functional washing tank, and a final washing tank, respectively. The wafer cassette 3 is sequentially moved from the wafer cassette table 13 through the tanks 14, 15, and 16 by the transfer arm 9, and is processed.
Finally, drying is performed in the drying unit 17. In addition, 18 shows a draft. This automatic processing is automatically performed by the control unit 19. In addition, 11 is a gas shield.

[Problems to be solved by the invention]

Conventional wet processing equipment for semiconductor devices is configured as described above.To prevent the growth of a natural oxide film after light etching, a large amount of inert gas is required if the entire inside of the draft is replaced with an inert gas. And Further, the inert gas contains vapors of the respective liquids, and has a problem that the inert gas cannot be regenerated and used. In addition, when the entire apparatus is made into an inert gas, there is a problem that contact with the air and leakage increase, and a small amount of O ₂ is mixed to grow a natural oxide film. Furthermore, the leak of the inert gas from the large-sized device has a problem that an oxygen deficiency state occurs in the clean room.

The present invention has been made in order to solve the above-described problems.A small amount of inert gas is processed in an independent processing tank shielded, and the transfer is performed without exposing to the atmosphere. , and to obtain a wet-processing apparatus of the semiconductor device can be completely prevent contact with O _2.

[Means for solving the problem]

A wet processing apparatus for a semiconductor device according to the present invention includes a processing solution for immersing a substrate to be processed in a plurality of gas-shielded wafer processing tanks, a processing solution positioned under the processing solution, and A solution that circulates without mixing with the solution is stored, and the same solution as the lower layer solution is stored in a gas-shielded and horizontally extending transport path that communicates with each lower layer solution, and the solution in the transport path is stored. The substrate is moved in the horizontal direction to transfer the substrate between the wafer processing tanks, and a predetermined processing is performed in each processing solution.

[Action]

In the present invention, the solution for preventing the reaction between the processing tanks of the substrates to be processed from being exposed to the atmosphere is, for example, a fluorine inert liquid (trade name: Fluorinert, manufactured by 3M, USA)
And has low compatibility with aqueous solutions and various organic solvents,
In addition, since the specific gravity is large at 1.6 to 2.0, when mixed with the processing solution to be used, it always separates into two layers, and becomes a lower layer. further,
Since it is stable and electrically insulating, it does not react with the substrate even when it is transported through the substrate. Therefore,
The substrate and O ₂ in or during transport process contact can be prevented.

〔Example〕

 Hereinafter, an embodiment of the present invention will be described.

FIG. 1 is a configuration diagram of a wet processing apparatus for a semiconductor device showing one embodiment of the present invention. FIG. 1 (a) is a side view, and FIG. 1 (b) is a schematic top view thereof. In FIG. 1, 1 is a wafer cleaning tank, 2 is a wafer to be cleaned, and 3 is this wafer 2
, A filter, 5 a chemical liquid circulation pump, 6 a processing solution for processing the wafer 2 in the wafer cleaning tank 1, 7 a lower layer of the processing solution 6, A fluorine inert solution which is not mixed with the circulating processing solution 6, 8 is a transfer elevator for moving the wafer cassette 3 between the processing solution 6 and the fluorine inert solution 7, 9 is a transfer arm, 10 is an inlet / outlet of inert gas, 11 Denotes a gas shield, and 12 denotes a solution shutter.

FIG. 2 shows an automated tank connected to the basic units of FIG. 13 is a wafer cassette table, 14 is a first processing unit, 15 is a second processing unit, 16 is a third processing unit, 17 is a drying unit, 18 is a draft, and 19 is a control unit.

 Next, the operation will be described.

The wafer cassette 3 containing the wafer 2 is transported by the transfer arm 9
Moves through the fluorine inert solution 7. The solution shutter 12 is opened, and the wafer cassette 3 is sent to the transport elevator 8 lowered by the transport arm 9. Solution shutter 12
Is closed, the transport elevator 8 is moved into the processing solution 6, and a predetermined process is performed. O _{2 is} removed from the processing solution 6 by the gas shield 11. Generally, dissolved oxygen in pure water is about 30 ppb
As described above, a natural oxide film grows on the wafer surface. However, when the processing solution 6, for example, pure water for cleaning comes into contact with the atmosphere, the dissolved oxygen becomes several hundred ppb, and the natural oxide film grows. Therefore, the gas shield 11 shields the processing solution 6 from the atmosphere, and as a result, the dissolved oxygen of the processing solution 6 can be kept lower than 30 ppb. Further, the processing liquid overflowed by the chemical liquid circulation pump 5 and the filter 4 is cleaned and re-supplied. The processing liquid and the transport elevator 8 descend, return the wafer cassette 3 to the fluorine inert solution 7, open the solution shutter 12, and move the wafer cassette 3 to the transport arm 9.

 The transfer arm 9 moves sideways to execute the next process.

FIG. 2 is a view in which three types of units shown in FIG. 1 are connected, and a wafer cassette 3 placed on a wafer cassette table 13 is shown.
Moves through the fluorine inert solution 7 gas-shielded by the transfer arm 9, and moves through the processing solution 6 a of the first processing unit 14.
, And then moves to the second processing unit 15 and is processed with the processing liquid 6b. Finally, it is treated with the treatment liquid 6c of the third treatment unit 16 and dried by the drying unit 17.

As the above embodiment, when used in the light etching step of the semiconductor substrate processing process, an HF solution is used as the first processing solution 6a, and pure water is used as the second processing solution 6b and the third processing solution 6c. It was carried out. Ar gas was used as the inert gas. As the drying unit 17, spin drying and IPA steam drying were used.

In the above embodiment, the case of using the wet etching wet process is shown. However, as shown in FIG. 3, each unit is connected and (a) cleaning before diffusion, (b) peeling of nitride film,
(C) It may be used for resist stripping. That is, FIG. 3 shows an application to a wet process other than the light etch by connecting a plurality of units of the present invention of FIG. 1 and changing the processing solution 6 of each unit.

(A) The pre-diffusion cleaning process is a pre-diffusion cleaning process and includes seven units and a drying unit. Each processing solution 6
NH ₄ OH / H ₂ O ₂ , H ₂ O (QDR), HF, H ₂ O (QDR), HCl / H ₂ O ₂ , H ₂ O
(QDR) and H ₂ O (FR). D indicates a drying unit.

(B) The nitride film peeling is a nitride film peeling process, and the processing solution 6
The drying unit D includes four units including H ₃ PO ₄ , H ₃ PO ₄ , H ₂ O (QDR), and H ₂ O (FR).

(C) The resist stripping is a resist stripping process,
H ₂ SO ₄ / H ₂ O ₂ , H ₂ SO ₄ / H ₂ O ₂ , H ₂
O (QDR), H ₂ O (FR) are used, and the drying unit D is combined.

〔The invention's effect〕

As described above, the present invention provides a processing solution for immersing a substrate that requires processing in a plurality of gas-shielded wafer processing tanks, and a processing solution positioned below the processing solutions,
In addition, a solution that circulates without being mixed with each processing solution is stored, communicates with each lower layer solution, and stores the same solution as the lower layer solution in a gas-shielded and horizontally extending transport path, and is transported. Since the substrate is transported between wafer processing tanks by moving horizontally in the solution in the path and performing a predetermined process in each processing solution, each wafer is processed in a processing solution with very little dissolved oxygen. Is processed and O ₂ is also transported.
This has the effect of completely preventing the growth of a natural oxide film which causes a contact failure in a product semiconductor without contacting the semiconductor device. Further, since each processing tank is independently closed, the inert gas can be circulated, the amount of the inert gas used is small, and the running cost can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a wet processing apparatus according to one embodiment of the present invention. FIG. 1 (a) is a side view, FIG. 1 (b) is a top view, and FIG. FIG. 3 shows another embodiment of the present invention in which a plurality of processing apparatuses are connected and automated. FIG. 4 is a view in which the processing tanks of the wet processing apparatus shown in FIG. 1 are rearranged, FIG. 4 and FIG. FIG. 1 is a view showing a conventional wet processing apparatus. In the figure, 1 is a wafer cleaning tank, 2 is a wafer, 3 is a wafer cassette, 4 is a filter, 5 is a chemical circulation pump, 6 is a processing solution, 7 is a fluorine inert solution, 8 is a transport elevator, 9 is a transport arm, Reference numeral 10 denotes an inlet / outlet of an inert gas, 11 denotes a gas shield, and 12 denotes a solution shutter. The same reference numerals in each drawing indicate the same or corresponding parts.

Claims (1)

(57) [Claims] 1. A processing solution for immersing a substrate to be processed in a plurality of wafer processing tanks independently gas-shielded, and a processing solution positioned below the processing solution and mixed with each of the processing solutions. And the same solution as the solution in the lower layer is stored in a gas-shielded and horizontally extending transfer path. A wet processing apparatus for a semiconductor device, wherein the substrate is moved in a horizontal direction to transfer the substrate between the wafer processing tanks, and a predetermined processing is performed in each of the processing solutions.