JPH06264268A - Dry etching device - Google Patents

Abstract

(57) [Summary] [Purpose] When a large number of objects to be processed are sequentially etched, the etching rate can always be kept constant, and
It can be kept constant with the etching rate increased,
As a result, the etching process is performed quickly. [Composition] In a dry etching apparatus of a reaction chamber separation type, in which a gas activated in a discharge chamber is introduced into a reaction chamber through a gas transport pipe to etch an object to be processed, cooling heating for cooling or heating the gas transport pipe It is characterized by comprising a mechanism and a temperature control means for controlling the cooling and heating mechanism to maintain the temperature of the transport pipe at a constant temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry etching apparatus, and more specifically, it can maintain a constant etching rate when a large number of objects to be processed are successively etched, and moreover, it can be kept constant with a large etching rate. The present invention relates to a dry etching apparatus of a reaction chamber separation type, which can be maintained at a high temperature and can perform etching processing quickly.

[0002]

2. Description of the Related Art Among dry etching apparatuses, as shown in FIG. 5, in a dry etching apparatus of a reaction chamber separation type, a discharge chamber 1 for generating plasma and a reaction chamber 2 for etching are provided with a gas transport pipe 3. It is characterized by being separated via. That is, while a reactive gas such as CF ₄ , O ₂ and N ₂ is introduced into the discharge chamber 1 from the introduction tube 4, microwaves oscillated from a microwave power source (not shown) are introduced from the waveguide 5 into these reactions. Acting on the reactive gas, these reactive gases are excited and activated to be in a plasma state. This activated gas is introduced into the reaction chamber 2 via the gas transport pipe 3. In this way, the discharge chamber 1 and the reaction chamber 2 are separated from each other, and the gas pressure is usually about 0.1 Torr. Therefore, the electrons and ions generated in the discharge chamber 1 are attenuated in the gas transport pipe 3. , The influence of electrons and ions on the reaction chamber 2 can be ignored. By the activated gas, the object to be processed 7 placed on the placing plate 6 (for example,
(Wafer) is etched and these gases are exhausted
Exhausted through. As described above, since etching is performed by a pure chemical reaction by neutral active radicals, there is an advantage that an adverse effect on an object to be processed is extremely small.

[0003]

As described above, the dry etching apparatus of the reaction chamber separation type is an apparatus which causes less damage to the object to be processed and is effective for semiconductor manufacturing, for example. But,
For example, in a semiconductor manufacturing process, a large number of wafers (for example,
When 25 wafers are continuously etched,
Due to the heat from the discharge chamber 1, the temperature of the gas transport tube 3 tends to increase sequentially as the number of processed wafers increases. As a result, as the temperature increases sequentially, the etching rate also increases, and the etching depth tends to gradually increase. In this way, there is a change over time in which the etching depth gradually increases as a large number of wafers are sequentially etched. That is, the object to be etched first has a shallow etching depth, and the object to be processed in the latter half has a deep etching depth. As a result, there is a problem in that it is difficult to control etching, and the etching process is delayed.

Therefore, in the semiconductor manufacturing process using the reaction chamber separation type dry etching apparatus, it is required that the etching rate be maintained constant and not change with time when a large number of wafers are sequentially etched. That is, it is desired that the etching rate is the same for the first processed object and the latter processed object.

In addition, there is a demand for a rapid etching process, and there is a demand not only for always maintaining a constant etching rate, but also for maintaining a constant etching rate with a large etching rate.

The object of the present invention is to solve the above-mentioned problems of the prior art, and when a large number of objects to be processed are sequentially etched, the etching rate can always be kept constant, and An object of the present invention is to provide a dry etching apparatus which can maintain a constant etching rate in a large state and can perform etching processing quickly.

[0007]

In order to achieve this object, a dry etching apparatus according to the present invention has a discharge chamber for generating plasma and a reaction chamber for etching separated from each other and activated in the discharge chamber. In the dry etching apparatus of the reaction chamber separation type that guides the gas to the reaction chamber through the gas transport pipe and etches the object to be processed, the cooling and heating mechanism for cooling or heating the gas transport pipe and the cooling and heating mechanism are provided. The temperature control means for controlling and maintaining the temperature of the gas transport pipe at a constant temperature is provided.

[0008]

As described above, in the present invention, the temperature of the gas transportation pipe connecting the discharge chamber and the reaction chamber is maintained at a constant temperature. Therefore, the object to be processed is etched in the reaction chamber by the activated gas which is always maintained at a constant temperature. Therefore, the etching rate is always kept constant and the etching depth is also kept constant. That is, the etching rate is the same and the etching depth is the same for both the first processed object and the latter processed object. As a result, the control of etching is facilitated, which in turn speeds up the etching process.

Moreover, the present inventor experimentally found that the etching rate increases as the temperature of the transport pipe increases. Accordingly, if the temperature of the transport pipe is constantly maintained at a high temperature, not only the etching rate can be maintained constant, but also the etching rate can be maintained constant with a large etching rate. As a result, the etching process can be performed extremely quickly.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A dry etching apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic structure of the dry etching apparatus of this embodiment. The same members as those in the conventional FIG. 5 are denoted by the same reference numerals.

In FIG. 1, a reactive gas such as CF ₄ , O ₂ and N ₂ is introduced into the discharge chamber 1 through an introduction pipe 4, while microwaves oscillated from a microwave power source (not shown) are conducted. The reactive gas acts on these reactive gases from the wave tube 5, and these reactive gases are excited and activated to be in a plasma state.

The activated gas is introduced into the reaction chamber 2 through the gas transport pipe 3. As described above, since the discharge chamber 1 and the reaction chamber 2 are separated from each other, the electrons and ions generated in the discharge chamber 1 are attenuated in the gas transport pipe 3, and the influence of the electrons and ions on the reaction chamber 2 is ignored. can do. The activated gas etches the object to be processed 7 (for example, a wafer) placed on the placing plate 6, and these gases are exhausted through the exhaust port 8.

In this embodiment, around the gas transport pipe 3,
A cooling and heating mechanism 11 is provided so as to cover this. The temperature of the gas transport pipe 3 is controlled by operating the cooling / heating mechanism 11.

Further, temperature control means for controlling the cooling / heating mechanism 11 to maintain the temperature of the transport pipe at a constant temperature is provided. This temperature control means controls the thermometer 12 for measuring the temperature of the gas transport pipe 3 and the cooling and heating mechanism 11 based on the temperature data from the thermometer 12, and as a result, keeps the temperature of the transport pipe constant. The temperature controller 13 controls the temperature.

That is, when the temperature of the transport pipe is below a certain temperature, the temperature controller 13 determines how much heating should be performed based on the temperature data from the thermometer 12, and the heating drive signal controls the temperature. It is sent from the machine 13 to the cooling / heating mechanism 11, and the cooling / heating mechanism 11 heats the gas transport pipe 3 to maintain it at a constant temperature. If necessary, feedback control is performed based on the temperature data from the thermometer 12. When the temperature of the transport pipe is equal to or higher than a certain temperature, the temperature controller 13 determines how much to cool based on the temperature data from the thermometer 12, and the cooling drive signal is sent from the temperature controller 13. Is sent to the cooling / heating mechanism 11, and the cooling / heating mechanism 11 cools the gas transport pipe 3 to maintain it at a constant temperature. If necessary, it is also feedback controlled.

FIG. 2 shows an object 7 to be etched by the apparatus of this embodiment. This object 7
Thermally oxidizes the Si substrate 14 to form a SiO ₂ layer 15, and then forms a reduced pressure CV on the SiO ₂ layer 15.
A layer 16 of polycrystalline Si is deposited by D.

Twenty-five pieces of the objects 7 to be processed were subjected to continuous etching processing by the dry etching apparatus of this embodiment, and changes with time of the etching rate were observed when the temperature of the gas transport pipe 3 was maintained at 25 ° C. . The results of this change over time are shown in FIG. FIG. 3 shows the relationship between the number of processed objects 7 and the etching rate of polycrystalline Si when the temperature of the activated gas in the gas transport pipe 3 is maintained at 25 ° C. It is understood that the etching rate of polycrystalline Si is always kept constant regardless of the number of processed wafers and does not change with time.

As described above, in this embodiment, the temperature of the activated gas in the gas transport pipe 3 is maintained at a constant temperature by the cooling / heating mechanism 11, the thermometer 12, and the temperature controller 13. Therefore, the object 7 is etched in the reaction chamber 2 by the activated gas which is always maintained at a constant temperature. Therefore, the etching rate is always kept constant and the etching depth is also kept constant. That is, the etching rate is the same and the etching depth is the same for both the first processed object and the latter processed object. As a result, the control of etching is facilitated, which in turn speeds up the etching process.

In this embodiment, the temperature range maintained constant is preferably 20 ° C. or higher and 150 ° C. or lower. This is because the melting temperature of the fluorine resin is 200 ° C. and the like.

Further, the present inventor has found that the polycrystalline S shown in FIG.
Using the object 7 having i, the temperature of the gas transport pipe 3,
The relationship with the etching rate of polycrystalline Si was obtained. Figure 4
Shows the result of this relationship. It was observed that as the temperature of the gas transport pipe 3 was increased, the etching rate of polycrystalline Si was also increased, and this tendency continued until 150 ° C.

As described above, the etching rate greatly depends on the temperature of the gas transport pipe 3, and the higher the transport pipe temperature, the higher the etching rate. Therefore, if the temperature of the transport pipe is constantly kept at a high temperature, not only the etching rate can be kept constant, but also the etching rate can be kept constant in a large state. That is, the etching depth can be always kept deep and constant. As a result, the etching process can be performed extremely quickly.

The present invention is not limited to the above-mentioned embodiments, and can be variously modified. For example,
The temperature range in which the activation gas is maintained constant is not limited to that of the embodiment, and the present invention is applicable to any reaction chamber separation type dry etching apparatus.

[0024]

As described above, in the present invention, since the temperature of the gas transport pipe is maintained at a constant temperature, the etching rate is always maintained constant and the etching depth is also maintained constant. As a result, the control of etching is facilitated, which in turn speeds up the etching process.

Moreover, if the temperature of the transport pipe is constantly kept at a high temperature, not only the etching rate can be kept constant, but also the etching rate can be kept constant in a large state. As a result, the etching process can be performed extremely quickly.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a dry etching apparatus of a reaction chamber separation type according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an object to be processed that is etched by a reaction chamber separation type dry etching apparatus according to an embodiment of the present invention.

FIG. 3 is a graph showing the relationship between the number of processed objects and the etching rate.

FIG. 4 is a graph showing the relationship between the temperature of the activated gas in the gas transport pipe and the etching rate.

FIG. 5 is a schematic configuration diagram of a conventional reaction chamber separation type dry etching apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Discharge chamber 2 Reaction chamber 3 Gas transport pipe 7 Object to be treated 11 Cooling and heating mechanism 12 Thermometer (temperature control means) 13 Temperature controller (temperature control means)

Claims (2)

[Claims] 1. A discharge chamber for generating plasma and a reaction chamber for etching are arranged separately from each other, and a gas activated in the discharge chamber is introduced into the reaction chamber through a gas transport pipe to etch an object to be processed. In the dry etching apparatus of the reaction chamber separation type for performing the above, a cooling and heating mechanism for cooling or heating the gas transport pipe, and a temperature control for controlling the cooling and heating mechanism to maintain the temperature of the gas transport pipe at a constant temperature. A dry etching apparatus comprising: 2. The dry etching apparatus according to claim 1, wherein the temperature range kept constant by the temperature control means is 20 ° C. or higher and 150 ° C. or lower.