JPH02177327A - Cleaning of semiconductor wafer, etching thereof and semiconductor wafer treatment device - Google Patents

Abstract

PURPOSE:To eliminate a contaminant or an unneeded object positively by supplying a cleaning liquid to a wafer after exposing the semiconductor wafer to a stream environment which is soluble to the semiconductor wafer cleaning liquid. CONSTITUTION:A wafer 12 is attached to a vacuum chuck 13 of a treatment tank 11 and the treatment tank 11 is sealed by a covering body 11b. Then, a steam generator 15 is used to generate a stream 23 which is easily soluble in a cleaning liquid or an etching liquid. In this case, a controller 16 is operated to control pressure of a steam 23 and dew is formed on the wafer 12. The steam 23 is fed into a trench groove 21 and air 22 within the groove 21 is replaced by the steam 23. Then, a treatment liquid 24 consisting of the cleaning liquid or the etching liquid is fed from a treatment liquid supply tube 18 to the wafer 12, thus eliminating contaminants or unneeded objects on the wafer 12. Since the steam 22 within the groove 21 is easily soluble in the treatment liquid 24, the treatment liquid enters the groove 21 and cleans it.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for cleaning or etching a semiconductor wafer in which a trench groove with a narrow opening width is formed on the surface thereof, and a method for carrying out this cleaning and etching. The present invention relates to a processing apparatus for semiconductor wafers that can be used for various purposes.

[Conventional technology]

In recent years, the miniaturization of semiconductor integrated circuits has progressed, and semiconductor wafers (
The structure of circuits formed on the surface of wafers (hereinafter simply referred to as wafers) is becoming more complex. For this reason, contaminants and unnecessary substances on the wafer surface must be reliably removed by cleaning or etching. A conventional cleaning method and etching method of this type will be explained with reference to FIG.

FIG. 4 is a schematic configuration diagram showing a conventional cleaning processing apparatus. In the same figure, 1 indicates a cleaning tank, and a wafer support 3 on which a wafer 2 is placed is attached in the cleaning tank 1. There is. 4 is a processing liquid such as a cleaning liquid or an etching liquid;
It is stored in the cleaning treatment tank 1. In order to clean or etch the wafer 2 using such a cleaning tank 1, the inside of the cleaning tank 1 is filled with the processing liquid 4 in advance, and the wafer 2 is immersed in the processing liquid 4 to support the wafer. Place it on table 3. Then, in order to improve the cleaning efficiency, ultrasonic energy is applied to the processing liquid 4 and the wafer 2, and the processing liquid 4 is pressurized so that the entire surface of the wafer X2 is evenly and uniformly wetted with the processing liquid 4. Cleaning or etching is performed. In addition to the method of immersing the wafer 2 in the processing liquid 4 to perform cleaning and etching processing as described above, it is also possible to mount the wafer 2 on the wafer support stand 3 in a state where the processing liquid 4 is not supplied. A method has also been adopted in which the pressure around the wafer 2 is reduced and then the processing liquid 4 is supplied to the wafer 2.

[Problem to be solved by the invention]

However, when the structure of the circuit formed on the surface of the wafer becomes complicated, a groove is formed on the surface of the wafer whose opening width is narrow compared to the depth dimension (hereinafter, this groove is referred to as a trench groove). However, conventional cleaning and etching methods have not been able to completely remove contaminants and unnecessary materials within the trenches. FIG. 5 shows a state in which a processing liquid is supplied to a wafer in which trenches are formed. In FIG. 5, reference numeral 5 indicates a trench groove, and reference numeral 6 indicates gas remaining in the trench groove 5 before the cleaning and etching processes. That is, since the opening width dimension of the trench groove 5 is extremely narrow, as shown in FIG. This is because it becomes difficult to replace the gas 6 inside the trench groove 5 with the processing liquid 4 using the energy of the pressurization and depressurization method. Incidentally, as the trench groove 5, a fine trench groove having an opening width of 1 μm or less and a depth of 2 μm to 20 μm is emerging.

[Means to solve the problem]

A semiconductor wafer cleaning method according to the present invention involves exposing the semiconductor wafer to a vapor atmosphere that is easily soluble in the cleaning liquid, and then supplying the cleaning liquid to the semiconductor wafer. Further, in the method of etching a semiconductor wafer according to the present invention, the semiconductor wafer is exposed to a vapor atmosphere that easily dissolves in the etching solution, and then the etching solution is supplied to the semiconductor wafer. Furthermore, the semiconductor wafer processing apparatus according to the present invention includes a steam generator that generates steam that is easily soluble in the processing liquid, in a sealed container that includes a wafer support base on which the semiconductor wafer is fixed and is supplied with the processing liquid; A temperature controller that maintains the temperature inside the closed container at a temperature higher than the dew point temperature of the steam is connected to an exhaust duct that exhausts the steam.

[For production]

By exposing the semiconductor wafer to a vapor atmosphere that is easily soluble in a cleaning solution or an etching solution, the vapor in the trenches of the semiconductor wafer is replaced with the vapor. Next, by supplying a cleaning liquid or an etching liquid to the semiconductor wafer, the vapor in the trenches is dissolved in the processing liquid, and the processing liquid also enters the trenches. Further, in the semiconductor wafer processing apparatus according to the present invention, the vapor pressure in the closed container is controlled by the temperature regulator, and it is possible to prevent the condensation of momme on the semiconductor wafer.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2.

FIG. 1 is a sectional view showing a semiconductor wafer processing apparatus used in the cleaning method and etching method of the present invention, and FIG.
a) to (d) are enlarged sectional views of essential parts of a semiconductor wafer for explaining a cleaning method and an etching method according to the present invention. In these figures, 1) is a processing tank for performing cleaning or etching processing on the wafer 12, and this processing tank 1) includes a main body 1) a and a lid body tib that closes the upper opening of the main body 1) a. The lid body 1)b is mounted on the main body 1)a to form a sealed space inside. 13 is a vacuum chuck for supporting the wafer 12, and this vacuum chuck 13 is attached to the bottom of the processing tank 1),
It is connected to a control device 14 located below the processing tank 1). 15 is a steam generator for generating steam that is easily soluble in the cleaning liquid or etching liquid, and this steam generator 15 is connected to a steam supply tank 15 for storing the liquid to be evaporated.
a, and a heating member 15b that is placed in the steam supply tank 15a and heats the liquid, and is attached to the bottom of the processing tank 1). In addition, n17 heating member 15b
is connected to a controller 16 placed outside the treatment tank 1, and is heated to equalize the pressure of the generated steam. ! The amount is adjusted. Note that the cleaning liquid or etching liquid contains hydrofluoric acid, nitric acid, and hydrochloric acid as vapors that are easily soluble in the cleaning liquid or etching liquid.

Alcohol-based (ethyl alcohol, methyl alcohol, isopropyl alcohol, etc.) vapor is used in the case of ammonia and hydrogen peroxide, and water vapor is used in the case of sulfuric acid. Reference numeral 17 denotes a temperature regulator for maintaining the temperature inside the processing tank 1) at a temperature higher than the dew point temperature of the steam. Connected to I6. That is, the pressure of the steam generated by the steam generator 15 is controlled to a predetermined pressure by the controller 16 controlling the heating member 15b and the temperature regulator 17. Condensation of steam is prevented. 18 is a processing liquid supply pipe for supplying cleaning liquid or etching liquid to the wafer 12;
It is attached to a portion of the lid body 1) b facing the wafer 12. Reference numeral 19 denotes an exhaust duct for discharging the steam from inside the processing tank 11, which is attached to the bottom of the processing tank 1). In FIG. 2, reference numeral 21 indicates a trench groove formed in the wafer 12, 22 indicates gas remaining in the trench groove 21 from the previous process, 23 indicates vapor that is easily soluble in the cleaning liquid or etching liquid, and 24 indicates the cleaning liquid or etching liquid. A processing solution consisting of an etching solution is shown.

Next, the cleaning method and etching method of the present invention will be explained. Although the cleaning method and the etching method use different processing liquids, they can be carried out by the same processing apparatus, so in this embodiment, both methods will be explained at the same time.

First, the wafer 12 is mounted on the vacuum chuck 13 of the processing tank 1), and the inside of the processing tank 11 is sealed with the lid 1)b.

At this time, the inside of the trench groove 21 of the wafer 12 is as shown in FIG.
), gas 22 remains. Next, the steam generator 15 generates steam 23 that is easily soluble in the cleaning liquid or etching liquid, and the steam 23 is introduced into the processing tank 1).
to fill up. At this time, the pressure of the steam 23 is controlled by operating the controller 16 to prevent dew condensation on the wafer 12. In this state, the wafer 12 is
Since the steam 23 can easily enter the trench groove 21, the steam 23 is sent into the trench groove 21, as shown in FIG. 2(b).
The gas 22 and steam 23 in this trench groove 21 are replaced. Thereafter, a processing liquid 24 consisting of a cleaning liquid or an etching liquid is supplied to the wafer 1 from the processing liquid supply pipe 18.
2, the wafer 12 is cleaned or etched, and contaminants and unnecessary substances on the wafer 12 are removed. When the processing liquid 24 is supplied onto the wafer 12, the opening of the trench groove 21 is closed by the processing liquid 24 immediately after the supply, as shown in FIG. Since the treatment liquid 24 is easily soluble in water, the treatment liquid 24 gradually enters the trench groove 21, as shown in FIG. 2(d). In this state, the inside of the trench groove 21 is also cleaned or etched.

FIG. 3 is a diagram showing another embodiment of the semiconductor wafer processing apparatus according to the present invention, in which the same or equivalent members as those explained in FIG. 1 are denoted by the same reference numerals. A detailed explanation will be omitted. In FIG. 3, reference numeral 31 denotes a vacuum pump for forcibly exhausting the steam in the process 4g1l, and is connected to the exhaust duct 19 via a damper 32. Reference numeral 33 denotes a steam supply member for supplying steam 23, which is easily soluble in the cleaning liquid or etching liquid, into the processing tank 1I. )It is connected to the. In the semiconductor wafer processing apparatus configured as described above, after the steam 23 is filled in the processing tank II, the steam 23 is once discharged to the outside of the processing tank 1) by the vacuum pump 31, and then returned to the processing tank II. The steam 23 can be replaced by supplying the steam 23 to.

That is, by repeating this operation of exchanging the steam 23 a plurality of times, the gas in the trench groove (not shown) is reliably replaced with the steam 23.

Note that in the semiconductor wafer processing apparatus used in the embodiments shown in FIGS. 1 and 3, the vacuum chuck 13 that supports the wafer 12 is of a fixed type, but the present invention is not limited to such limitations. Vacuum chuck I without being removed
3 may be rotated by connecting a drive device.

〔Effect of the invention〕

As explained above, the semiconductor wafer cleaning method according to the present invention is a method in which the semiconductor wafer is exposed to a vapor atmosphere that is easily soluble in the cleaning liquid, and then a cleaning liquid is supplied to the semiconductor wafer. In this etching method, the semiconductor wafer is exposed to a vapor atmosphere that is easily soluble in the etching liquid, and then the etching liquid is supplied to the semiconductor wafer. By this, the gas in the trenches in the semiconductor wafer is replaced with the vapor, and then by supplying a cleaning liquid or an etching liquid to the semiconductor wafer, the vapor in the trenches is dissolved in the processing liquid, and the processing is also carried out in the trenches. Liquid will be infiltrated.

Furthermore, the semiconductor wafer processing apparatus according to the present invention includes:
A closed container that includes a wafer support to which semi-integrated wafers are fixed and to which a processing solution is supplied is provided with a steam generator that generates steam that is easily soluble in the processing solution, and a temperature inside the closed container that is lower than the dew point temperature of the vapor. Since a temperature controller that maintains a high temperature is connected to an exhaust duct that exhausts the steam, the temperature controller controls the steam pressure inside the closed container, and prevents the steam from condensing on the semiconductor wafer. be able to.

Therefore, it is possible to reliably remove contaminants and unnecessary substances in the trenches of the semiconductor wafer, thereby improving the yield and producing semiconductors with high reliability.
A product circuit can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a semiconductor wafer processing apparatus used in the cleaning method and etching method of the present invention, and FIG.
a) to (d) are enlarged sectional views of main parts of a semiconductor wafer for explaining the cleaning method and etching method according to the present invention;
FIG. 3 is a diagram showing another embodiment of the semiconductor wafer processing apparatus according to the present invention, FIG. 4 is a schematic configuration diagram showing a conventional cleaning processing apparatus, and FIG. 5 is a diagram showing a cleaning solution used in a conventional cleaning method or etching method. Alternatively, it is a sectional view showing a state in which an etching liquid is supplied to a semiconductor wafer. 1)...Processing tank, 12...Semiconductor wafer, 13
...Vacuum chuck, 15...Steam generator, 17
... Temperature controller, 19 ... Exhaust duct, 21.
... trench groove, 23 ... steam, 24 ... processing liquid. Figure 1 Figure 2 (a) (b)

Claims (3)

[Claims] (1) A method for cleaning a semiconductor wafer, which comprises exposing the semiconductor wafer to a vapor atmosphere that is easily soluble in the cleaning liquid, and then supplying the cleaning liquid to the semiconductor wafer. (2) A method for etching a semiconductor wafer, which comprises exposing the semiconductor wafer to a vapor atmosphere that is easily soluble in the etching solution, and then supplying the etching solution to the semiconductor wafer. (3) A steam generator that generates steam that is easily soluble in the processing solution is installed in a sealed container that includes a wafer support to which the semiconductor wafer is fixed and is supplied with a processing solution, and the temperature inside this sealed container is adjusted to the dew point of the vapor. a temperature controller that maintains the temperature higher than the temperature;
A semiconductor wafer processing apparatus, characterized in that it is connected to an exhaust duct for exhausting the steam.