JPH06283492A - Vapor washer - Google Patents

Abstract

PURPOSE:To condense the mixed vapor of chemicals and a solvent stably on a wafer surface uniformly at all times by disposing a cooling means cooling a chamber at the condensation temperature or lower of the mixed vapor on the outer circumference of the chamber. CONSTITUTION:Heat-insulating materials 16a, 16b are bonded with the outer circumferences of a chamber body 11 and a bottom plate member 12, and a cooling means 17 is composed of a chiller 15, a refrigerant supply pipe 15a, a refrigerant path 13, a refrigerant discharge pipe 15b and the heat-insulating plates 16a, 16b. A refrigerant 18 at a fixed temperature and a fixed flow rate cooled by the chiller 15 is circulated in a path reaching the refrigerant supply pipe 15a, the refrigerant path 13, the refrigerant discharge pipe 15b and the chiller 15. Consequently, the chamber body 11 is cooled by conduction, a chamber 10 is cooled at a fixed temperature of the condensation temperature or lower of mixed vapor 50, and a wafer 44 is cooled at the condensation temperature or lower. Accordingly, the mixed vapor of chemicals and the solvent can be condensed stably on a wafer surface uniformly at all times.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor cleaning apparatus, and more particularly, it is used for removing an oxide film or the like formed on a wafer surface by a chemical vapor such as hydrogen fluoride in a semiconductor manufacturing process. Related vapor cleaning device.

[0002]

2. Description of the Related Art It is said that a wafer cleaning step accounts for about 40% in a semiconductor manufacturing process, and the cleaning step is extremely important. Currently, the wet process is mainly used for cleaning the wafer. However, the removed metal and chemical substances are re-adhered to the wafer during the wet process, and a natural oxide film is regrown on the wafer during the pure water rinsing process. There was a problem of doing. To address these issues,
In recent years, dry cleaning using a hydrogen fluoride (hereinafter referred to as HF) vapor has begun.

FIG. 7 is a sectional view schematically showing a vapor cleaning processing apparatus used in a conventional dry cleaning process.
In the figure, 40 indicates a chamber. The chamber 40 is formed in a substantially hollow hemispherical shape by a chamber body 41 having a substantially hemispherical outer shape and a bottom plate member 42 having a substantially disk shape. The chamber body 41 and the bottom plate member 42 are made of silicon carbide (hereinafter referred to as SiC). Note)). A sample table 43 is arranged in the chamber 30, and a wafer 44 is placed on the sample table 43. Bottom plate member 42
Is fixed to the chamber main body 41 using a fixing member (not shown), and the O-ring 42a is formed on the outer peripheral upper surface of the bottom plate member 42.
Is provided, and the chamber 40 is hermetically held by the O-ring 42a.

On the other hand, a substantially cylindrical intermediate ring 45 is connected to the upper part of the chamber body 41 through an O-ring 46a, and a substantially pipe-shaped nozzle 47 is connected to the upper part of the intermediate ring 45 through an O-ring 46b. Connected. A mixing chamber 47c and a discharge hole 47d are formed in the nozzle 47 so as to communicate with the chemical liquid hole 47a and the solvent hole 47b, and a heater 48 is embedded in the nozzle 47.
A power source 48a is connected to the switch 8. Further, an exhaust pump 57 is connected to the side surface of the intermediate ring 45 via an exhaust pipe 57a.

A supply pipe 51 is provided in the chemical liquid hole 47a of the nozzle 47.
The chemical liquid tank 52 is connected via a, the chemical liquid tank 52 is filled with HF 53, and the heater 52 a is arranged on the outer periphery of the chemical liquid tank 52. In addition, the nozzle 47
Via the supply pipe 51b to the solvent hole 47b of the solvent tank 5
4 is connected, and water (hereinafter,
H ₂ O) 55 is filled, and a heater 54 a is arranged on the outer periphery of the solvent tank 54. Further chemical liquid tank 52, respectively the carrier gas introducing pipe 56a to solvent tank 54, nitrogen (not shown) via the 56b (hereinafter, referred to as N ₂₎ gas cylinder is connected.

When the natural oxide film (hereinafter referred to as an oxide film) formed on the surface of the wafer 44 is cleaned and removed by using the apparatus thus configured, the wafer 4 is first placed on the sample table 43.
After mounting No. 4, the exhaust pump 57 is driven to decompress the chamber 40 to a predetermined pressure, the power supply 48a is turned on to energize the heater 48, and the nozzle 47 is heated to a predetermined temperature. Next, the heaters 52a and 54a are energized to heat the chemical liquid tank 52 and the solvent tank 54 to a predetermined temperature, and HF 53 and H ₂ O are added.
Generate 55 vapors. Next, N ₂ gas is caused to flow through the chemical liquid tank 52 and the solvent tank 54, and HF 53 and H _{2 are} discharged.
O55 vapor is supplied to the nozzle 47 through the supply pipes 51a and 51b. And the HF mixed in the mixing chamber 47c
53 and H ₂ O 55 mixed vapor 50 is discharged through the outlet 47d.
To be ejected into the chamber 40. Then, the mixed vapor 50 reaching the surface of the wafer 44 is condensed, and a chemical reaction occurs between the oxide film and HF in the mixed vapor 50 to generate a reaction product that is easily vaporized and separated, and this reaction product is vaporized. As a result, the wafer 44 is cleaned and removed from the surface, and is discharged to the outside of the chamber 40 by the exhaust pump 57.

[0007]

In the vapor cleaning apparatus described above, it is necessary to condense the mixed vapor 50 on the surface of the wafer 44 as a precondition for causing a chemical reaction between the HF and the oxide film. This condensation is greatly affected by the temperature, and is easily condensed when the temperature is low, but difficult when the temperature is high. However, since the temperature of the chamber 40 changes depending on the room temperature where the chamber 40 is installed, the number of times the apparatus is operated, and the like, there is a problem that the degree of condensation of the mixed vapor 50 changes for each process, or the temperature distribution in the chamber 40 varies. Since it is likely to be nonuniform, there is a problem that the condensation on each part of the surface of the wafer 44 is nonuniform. As a result, the quality of each cleaning process is not stable, and the wafer 4
There is a problem that the etching of the oxide film in the four planes tends to be non-uniform.

The present invention has been made in view of the above problems, and a mixed vapor of a chemical solution and a solvent can always be stably and uniformly condensed on a wafer surface, and oxides on the wafer surface are always It is an object of the present invention to provide a vapor cleaning device capable of cleaning and removing stably and uniformly.

[0009]

In order to achieve the above object, a vapor cleaning apparatus according to the present invention comprises a nozzle for ejecting a mixed vapor of a chemical solution and a solvent into a chamber in which a sample stage is arranged. In the vapor cleaning apparatus in which the chemical liquid tank and the solvent tank are respectively connected via a supply pipe, cooling means for cooling the chamber below the condensation temperature of the mixed vapor is arranged on the outer circumference of the chamber. There is.

[0010]

According to the vapor cleaning apparatus of the present invention, since the cooling means for cooling the chamber below the condensation temperature of the mixed vapor is disposed on the outer circumference of the chamber, the chamber is kept at a predetermined temperature below the condensation temperature. The wafer surface is cooled stably and uniformly, so that the wafer surface is cooled to the condensation temperature or less in a stable and uniform manner, and the mixed vapor reaching the wafer surface is condensed on the wafer surface. Then, the oxide film formed on the wafer surface reacts with the condensed chemical in the mixed vapor to be removed by etching.

[0011]

EXAMPLES AND COMPARATIVE EXAMPLES Examples of a vapor cleaning apparatus according to the present invention will be described below with reference to the drawings. It should be noted that components having the same functions as those of the conventional example are designated by the same reference numerals. FIG. 1 is a schematic cross-sectional view showing an embodiment (1) of a vapor cleaning apparatus according to the present invention, and 11 in the drawing shows a chamber body which will be described in detail later. Similar to the conventional one, a substantially cylindrical intermediate ring 45 is connected to the upper part of the chamber body 11 via an O-ring 46a.
In the upper part of the nozzle 5, a nozzle 47 formed in a substantially pipe shape is
It is connected via a ring 46b. The nozzle 47 communicates with the chemical solution hole 47a and the solvent hole 47b and is connected to the mixing chamber 47.
c, a discharge hole 47d is formed, a heater 48 is embedded in the nozzle 47, and the heater 48 has a power source 48a.
Are connected. Further, an exhaust pump 57 is connected to the side surface of the intermediate ring 45 via an exhaust pipe 57a.

Further, like the conventional one, a chemical solution tank 52 is connected to the chemical solution hole 47a through a supply pipe 51a, the chemical solution tank 52 is filled with HF53, and the heater 52a is provided on the outer periphery of the chemical solution tank 52. Is provided. Further, the solvent tank 5 is connected to the solvent hole 47b through the supply pipe 51b.
4 is connected, and H ₂ O 55 is stored in the solvent tank 54.
And a heater 54a is provided on the outer periphery of the solvent tank 54. Furthermore, the chemical liquid tank 52 and the solvent tank 5
An N ₂ cylinder (not shown) is connected to the No. 4 via carrier gas introducing pipes 56a and 56b.

The chamber 10 has a chamber body 11 having a substantially rectangular parallelepiped outer shape and a bottom plate member 1 having a substantially square flat body shape.
2 and the chamber body 11 and the bottom plate member 12 are made of SiC or graphite. Chamber body 11 and bottom plate member 12
The inner surface of the chamber is coated with a high-purity SiC thin film (not shown) by the CVD method so that the chamber 10 is not contaminated by impurities in the chamber body 11 and the bottom plate member 12. Similar to the conventional one, a sample table 43 is arranged in the chamber 10, and a wafer 44 is placed on the sample table 43. Further, the bottom plate member 12 is fixed to the chamber main body 11 using a fixing member (not shown) through the O-ring 12a, so that the chamber 1
0 is kept airtight.

A continuous refrigerant passage 13 is formed inside the chamber body 11, an inlet portion 14a of the refrigerant passage 13 is connected to one end of a refrigerant supply pipe 15a, and an outlet portion 14b of the refrigerant passage 13 is connected to a refrigerant discharge pipe 15b. Is connected to one end, and the chiller 15 is connected to the other ends of the refrigerant supply pipe 15a and the refrigerant discharge pipe 15b. Furthermore, the chamber body 1
1. On the outer periphery of the bottom plate member 12, a heat insulating plate 16 made of foam resin is provided.
The chiller 15, the coolant supply pipe 15a, the coolant passage 13, the coolant discharge pipe 15b, and the heat insulating plates 16a and 16b constitute a cooling means 17 to which a and 16b are adhered. Then, the coolant (for example, water) 18 having a predetermined temperature and flow rate cooled by the chiller 15 is supplied to the coolant supply pipe 15a and the coolant passage 1.
3, the cooling medium discharge pipe 15b and the chiller 15 are circulated to cool the chamber body 11 by conduction, the chamber 10 is cooled to a predetermined temperature below the condensation temperature of the mixed vapor 50, and the wafer 44 is below the condensation temperature. It is supposed to be cooled.

FIG. 2 is a horizontal sectional view showing a continuous refrigerant passage 13 formed inside the chamber body 11. In the drawing, 10 is a chamber, and 13a to 13h are holes forming a part of the refrigerant passage 13, respectively. Shows. A hole 13a is formed perpendicularly to the side surface 11a of the chamber body 11 by machining or the like, and the end portion of the hole 13a has a side surface 11b.
Is connected to the hole 13b opened in the oblique direction, and holes 13c to 13g are further formed and connected by the same method as in the case of the holes 13a and 13b. Also the hole 13
A hole 13h is formed at the terminal end of g in the upward direction in a side view, and is connected to another hole group (not shown) formed above the holes 13a to 13g. The open ends of the holes 13b to 13g are closed by the plugs 18a and 18b to form the continuous refrigerant passage 13, and the refrigerant 1 is supplied from the refrigerant supply pipe 15a connected to the inlet 14a of the refrigerant passage 13.
When 8 is supplied, this flows in the refrigerant passage 13 in the order of the holes 13a, 13b, ..., And the outlet portion 14b.

When the oxide film formed on the surface of the wafer 44 is cleaned using the apparatus thus configured,
First, after placing the wafer 44 on the sample table 43, the chiller 15
Is driven to circulate the refrigerant 18 in the refrigerant passage 13 to cool the chamber 10 to a predetermined temperature below the condensation temperature of the mixed vapor. Next, the exhaust pump 57 is driven to reduce the pressure of the chamber 10 to a predetermined pressure, the power source 48a is turned on to energize the heater 48, and the nozzle 47 is heated to a predetermined temperature. Next, the heaters 52a and 54a are energized to supply the chemical liquid tank 5
2, a solvent tank 54 is heated to a predetermined temperature, to generate a HF53 and H ₂ O55 Total supermarkets. Next, N ₂ gas is caused to flow through the chemical liquid tank 52 and the solvent tank 54, and vapors of HF 53 and H ₂ O 55 are caused to flow through the supply pipes 51 a and 51 b and are supplied to the nozzle 47. Then, the mixed vapor 50 of HF53 and H ₂ O55 mixed in the mixing chamber 47c is jetted into the chamber 10 from the discharge port 47d. Then, the mixed vapor 50 reaching the wafer 44 is condensed on the surface of the wafer 44 cooled to the condensation temperature or lower, and a chemical reaction occurs between the HF and the oxide film to generate a reaction product which is easily vaporized and separated. The wafer 4 is formed by vaporizing the product.
4 is washed and removed from the surface, and is discharged to the outside of the chamber 10 by the exhaust pump 57.

Hereinafter, the etching depth and the in-plane uniformity of etching on the surface of the wafer 44 when the oxide film formed on the surface of the wafer 44 is cleaned by using the vapor cleaning apparatus according to the embodiment (1). The measurement results will be described. As cleaning conditions, the heating temperature of the chemical liquid tank 52 and the solvent tank 54 is about 50 ° C., and the temperature of the nozzle 47 is about 10 ° C.
It was set to 0 ° C. Further, a coolant (water) 18 whose temperature and flow rate are controlled is circulated in the coolant passage 13 so that the temperature of the chamber 10 is approximately 10 to 2 below the condensation temperature in the mixed vapor 50.
It was set to 0 ° C. As a comparative example, using the apparatus shown in FIG. 1, the heating temperature of the chemical liquid tank 52 and the solvent tank 54 was set to about 50 ° C., the temperature of the nozzle 47 was set to about 100 ° C., and the cleaning process was performed without flowing the refrigerant 18. The case will be described.

FIG. 3 is a graph showing the results of measuring the etching amount on the wafer 44 for each cleaning process.
(A) shows the case of Example (1), (b) has shown the case of a comparative example. As is clear from FIG. 3, the etching amount in the comparative example varies depending on the lot, but in the case of the example (1), this variation could be reduced.

FIGS. 4A and 4B are views showing the results of measuring the in-plane uniformity of the wafer 34 after the cleaning process. FIG. 4A shows the case of the embodiment (1), and FIG. 4B shows the case of the comparative example. ing. As is clear from FIG. 4, the variation in etching is ± 7% in the case of the comparative example, while it is ± 1.2% in the case of the example (1). When used, the etching treatment could be performed with good in-plane uniformity.

As is clear from the above results, in the vapor cleaning apparatus according to the embodiment (1), the mixed vapor 50
Chiller 1 for cooling the chamber 10 below the condensation temperature of
5, refrigerant supply pipe 15a, refrigerant passage 13, refrigerant discharge pipe 15
Since the cooling means 17 composed of b and the heat insulating plates 16a and 16b is arranged on the outer periphery of the chamber 10,
0 is below the condensation temperature of the mixed vapor 50 (10 to 20 ° C.)
It can be cooled stably and uniformly. Therefore, the surface of the wafer 44 can be cooled stably and uniformly within the surface, and the mixed vapor 50 reaching the surface of the wafer 44 can be condensed on the surface of the wafer 44 and formed on the surface of the wafer 44. The formed oxide film can be reacted with the condensed HF 53 in the mixed vapor 50 to be uniformly removed by etching.

FIG. 5 is a schematic sectional view showing a vapor cleaning apparatus according to the embodiment (2). The configuration of the apparatus shown in FIG. 5 is the same as that of the vapor cleaning apparatus shown in FIG. 1 except for the chamber main body 21 and the cooling jacket 23 formed on the outer periphery thereof, and therefore detailed description thereof will be omitted here. The configuration will be described only for the points different from those shown in FIG.

The chamber 20 is formed in a substantially hemispherical shape by a chamber main body 21 having a substantially hemispherical outer shape and a bottom plate member 22 having a substantially square flat shape, and the chamber main body 21 and the bottom plate member 22 are made of SiC or graphite. The inner surfaces of the chamber body 21 and the bottom plate member 22 are coated with a high-purity SiC thin film (not shown) by the CVD method. Similar to the one in the embodiment (1), the sample table 43 is arranged in the chamber 20, and the wafer 44 is mounted on the sample table 43. Further, the bottom plate member 22 is O
The chamber 20 is fixed to the chamber main body 21 with a fixing member (not shown) via the ring 22a, and the chamber 20 is hermetically held.

A cooling jacket 23 is disposed on the outer periphery of the chamber body 21 so as to be in close contact therewith. The cooling jacket 23 is made of aluminum or the like having excellent thermal conductivity and workability, and has a substantially rectangular parallelepiped outer shape. The continuous refrigerant passage 24 is formed in the interior thereof by a method substantially similar to that shown in FIG. Inlet 23 of refrigerant passage 24
One end of the refrigerant supply pipe 15a is connected to a, and the refrigerant passage 2
One end of the refrigerant discharge pipe 15b is connected to the outlet portion 23b of No. 4, and the chiller 15 is connected to the other ends of the refrigerant supply pipe 15a and the refrigerant discharge pipe 15. Further, the cooling jacket 23 and the bottom plate member 22 have a heat insulating plate 25 formed on the outer circumference thereof using a foamed resin or the like and formed to cover them.
a and 25b are adhered to each other, and these chiller 15, refrigerant supply pipe 15a, cooling jacket 23, refrigerant discharge pipe 15
b and the heat insulating plates 25a and 25b constitute the cooling means 26. Then, the coolant (for example, water) 18 having a predetermined temperature and flow rate cooled by the chiller 15 is circulated in the coolant supply pipe 15a, the coolant passage 24 in the cooling jacket 23, the coolant discharge pipe 15b, and the chiller 15 to cool the coolant. The jacket 23 and the chamber body 21 are cooled by conduction, the chamber 20 is cooled to a predetermined temperature below the condensation temperature in the mixed vapor 50, and the wafer 44 is cooled below the condensation temperature. Using the vapor cleaning apparatus of the embodiment (2) configured as described above, the refrigerant 18 is circulated in the refrigerant passage 24 in the cooling jacket 23, and otherwise the cleaning process is performed in substantially the same manner as that of the embodiment (1). When the above is performed, it is possible to obtain substantially the same effect as that of the embodiment (1).

FIG. 6 is a schematic sectional view showing the chamber 30 of the vapor cleaning apparatus according to the embodiment (3). The chamber-30 has a chamber body 31 having a substantially hemispherical outer shape.
And a bottom plate member 32 having a substantially disc shape are formed into a substantially hemispherical shape. The chamber body 31 and the bottom plate member 32 are formed using SiC or graphite, and the inner surfaces of the chamber body 31 and the bottom plate member 32 are A high-purity SiC thin film (not shown) is coated by the CVD method.
Further, as in the case of the embodiment (1), the bottom plate member 32 is fixed to the chamber body 31 via an O-ring 32c using a fixing member (not shown).

A groove 33 having a substantially semicircular cross section is continuously formed in a spiral shape by machining on the outside of the chamber body 31, and a heat insulating plate 34a is formed on the outer periphery of the chamber body 31 by using foamed resin or the like. Is glued and groove 3
3 is the refrigerant passage 35. Inlet 35a of groove 33
Is connected to one end of a refrigerant supply pipe 15a, the outlet portion 35b of the groove 33 is connected to one end of a refrigerant discharge pipe 15b, and the chiller 15 is connected to the other ends of the refrigerant supply pipe 15a and the refrigerant discharge pipe 15b. Has been done. Further, a heat insulating plate 34b made of foamed resin or the like is adhered to the lower surface of the bottom plate member 32, and these chiller 15 and refrigerant supply pipe 15
a, groove 33, refrigerant discharge pipe 15b, heat insulating plates 34a, 34b
The cooling means is constituted by. Then, a predetermined flow rate of the coolant (for example, water) 18 cooled by the chiller 15 is circulated through the coolant supply pipe 15a, the groove 33, the coolant discharge pipe 15b and the chiller 15 to cool the chamber body 31 by conduction. The chamber 30 is cooled to a predetermined temperature below the condensation temperature of the mixed vapor, and the wafer 44 is further cooled.
Is cooled below the condensation temperature. An oxide film formed on the surface of the wafer 44 in the same manner as in Example 1 except that the coolant (water) 18 is circulated in the groove 33 by using the vapor cleaning apparatus of Example (3) configured as described above. When the cleaning treatment of (1) is performed, it is possible to obtain substantially the same effect as that of the embodiment (1).

[0026]

As described in detail above, in the vapor cleaning apparatus according to the present invention, since the cooling means for cooling the chamber to the condensation temperature of the mixed vapor or less is arranged on the outer circumference of the chamber, Can be cooled stably or uniformly below the condensation temperature. Therefore, the wafer surface can be cooled stably and uniformly in-plane to the condensation temperature or less, and the mixed vapor reaching the wafer surface can be uniformly condensed on the wafer surface. The oxide film formed on the wafer surface can be uniformly etched and removed by reacting with the condensed chemical in the mixed vapor.

[Brief description of drawings]

FIG. 1 is an embodiment (1) of a vapor cleaning apparatus according to the present invention.
It is a schematic cross-sectional view showing.

FIG. 2 is a horizontal cross-sectional view shown for explaining an example of a method of forming a continuous refrigerant passage inside a chamber body.

FIG. 3 is a graph showing a result of measuring an etching amount of each cleaning process on a wafer, where (a) shows the case of the example (1) and (b) shows the case of the comparative example.

FIG. 4 is a diagram showing a result of measuring in-plane uniformity of a wafer after a cleaning process, wherein (a) shows the case of the example (1) and (b) shows the case of the comparative example.

FIG. 5 is a schematic sectional view showing a vapor cleaning apparatus according to an embodiment (2).

FIG. 6 is a schematic sectional view showing a chamber of a vapor cleaning apparatus according to an example (3).

FIG. 7 is a cross-sectional view schematically showing a vapor cleaning treatment apparatus used in a conventional dry cleaning treatment.

[Explanation of symbols]

10 Chamber 13 Refrigerant Passage 15 Chiller 15a Refrigerant Supply Pipe 15b Refrigerant Discharge Pipe 16a, 16b Heat Insulation Plate 17 Cooling Means 43 Sample Stand 47 Nozzle 50 Mixed Vapor 51a, 51b Supply Pipe 52 Chemical Liquid Tank 53 HF 54 Solvent Tank 55 H ₂ O

Claims (1)

[Claims] 1. A vapor cleaning apparatus in which a chamber provided with a sample table is provided with a nozzle for ejecting a mixed vapor of a chemical solution and a solvent, and the chemical solution tank and the solvent tank are connected to the nozzle via supply pipes, respectively. The vapor cleaning apparatus is characterized in that cooling means for cooling the chamber to a temperature equal to or lower than the condensation temperature of the mixed vapor is disposed on the outer circumference of the chamber.