JPH08153597A - Semiconductor processing device and method of processing - Google Patents

Abstract

PURPOSE: To provide a semiconductor processing device which enhances the rate of processing, suppresses variation of the processing rate and abnormal discharging of microwave, and ensures stable operation. CONSTITUTION: A comprises a plasma light emission chamber 3 for production of plasma by introducing microwaves from a microwave transmissive window and also introducing a process gas from a gas inlet 5, a processing chamber 6 located under the chamber 3 for performing the processing of an object to be processed 7, and a microwave shutoff flange 4D having a blocking plate 4B furnished apart from the flange 4D located under a transport hole for the down-flow of a reaction active seed from the chamber 3 in the central part between the chambers 3 and 6. The microwave shutoff flange 4D consists of a cavity provided in the form of a ring surrounding it, and processing of a semiconductor board is made by the use of this semiconductor processing device having a plurality of process gas introducing holes 5B leading to the plasma light emission chamber 3 from a process gas introduction part 5A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor processing apparatus and processing method for microwave-excited plasma downflow.

Plasma processing is used for isotropic etching of oxide films and ashing of organic resist films in semiconductor manufacturing processes. In recent years, semiconductor processing equipment has
There is a demand for faster and more stable plasma processing technology. Therefore, in the etching and ashing process, high speed and long-term stable operation of the equipment are desired.

[0003]

2. Description of the Related Art Next, a conventional example of a down-flow plasma processing apparatus of two types of microwave excitation will be described.

FIG. 2 is an explanatory view of the conventional example (1). In the figure, 1 is the microwave waveguide, 2 is the microwave transmission window,
3 is a plasma emission chamber (plasma generation chamber), 4 is a shower head (μ wave shielding plate), 5 is a process gas inlet, 6 is a processing chamber, and 7 is an object to be processed.

This apparatus uses a conductor called a shower head having a large number of holes to separate the plasma emission chamber and the processing chamber. With such a showerhead, the concentration of reactive species downflowing under the showerhead could not be finely controlled in the processing chamber, and there was a problem in stable operation of the equipment. Furthermore, the surface state of the shower head changes due to reactive species, which requires regular cleaning, which reduces the operating rate of the equipment.

FIG. 3 is an explanatory view of a conventional example (2) in which the above drawbacks are improved. This device has a ring-shaped gas inlet 5A connected to the gas inlet 5 in the plasma emission chamber 3.
The reactive species were obtained by microwave excitation on the microwave shielding flange 4A. The generated reactive species pass through the central hole, hit the shield plate 4B, and flow down from the surrounding area.

In this structure, the gas is blown out into the plasma emission chamber 3 from the entire circumference of the ring-shaped gas introduction part 5A, and there are places where a large amount of reactive species are generated and places where it is not. The distribution of active species was uneven.

Further, the microwave propagates into the ring-shaped gas introduction portion, which causes abnormal discharge of the microwave. In addition, the surface of the microwave shielding flange 4A is contaminated by the plasma of the reaction gas, which causes a reduction in the processing rate and requires regular cleaning of the equipment.

[0009]

As described above, even in the improved conventional example (2), there are problems of fluctuations in processing rate, stable operation, and abnormal microwave discharge.

An object of the present invention is to improve the structure of the microwave shielding flange to improve the processing rate, suppress fluctuations in the processing rate and abnormal microwave discharge, and to ensure stable operation of the apparatus.

[0011]

Means for Solving the Problems To solve the above-mentioned problems, 1) a plasma emission chamber for generating a gas plasma by introducing a microwave through a microwave transmission window and a process gas through a gas inlet, and below Between the plasma emission chamber and the processing chamber for processing the object to be processed, a transport hole for downflowing reactive species from the plasma emission chamber in the center, and a lower side of the transport hole. A microwave blocking flange having the microwave blocking flange and a shielding plate provided at a distance from the microwave blocking flange, and the microwave blocking flange is a process gas introducing section including a cavity provided in a ring shape around the microwave blocking flange. And a semiconductor processing device having a plurality of process gas introduction holes communicating from the process gas introduction part to the plasma emission chamber, or 2) the microwave blocking flange is the plasma This is achieved by a semiconductor processing method described in 1 above, which is screwed to a light emitting chamber, or 3) a semiconductor processing method in which a semiconductor substrate is processed using the apparatus described in 1 above.

[0012]

In the conventional example (2) and the present invention, the microwave shielding flange is installed at the center of the plasma emission chamber in order to make the charged particles less likely to leak from the plasma emission chamber to the object to be processed. The microwave shielding flange matches the microwave.

When tested with a microwave of 2.45 GHz, matching was achieved up to a distance of about 10 mm from the microwave transmission window, but a reflected wave was generated at a distance longer than that.
Therefore, it is necessary to shorten this distance to some extent.
For this reason, a structure in which a microwave shielding flange is provided in the central portion of the plasma emission chamber is used. However, in the conventional example (2), the problem as described above occurred, so the present invention uses the gas for the plasma emission chamber. The gas is introduced uniformly into the light-emitting chamber by introducing the gas through multiple holes, and the experimental results show that the diameter of the hole is λ / 20 (where λ is the wavelength of the microwave,
If it is less than 12.2 cm at 2.45 GHz, microwaves do not enter the process gas inlet and abnormal discharge does not occur here.

The reason why the present invention can uniformly introduce the gas into the light emitting chamber is that the gas introduced from the outside is temporarily stored in the ring-shaped gas introduction part and has a substantially uniform pressure over the entire circumference of the ring. This is because the gas is blown out from a plurality of holes provided around the ring, so that the holes are uniformly introduced into the plasma emission chamber.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an illustration of an embodiment of the present invention. In the figure, 1 is a microwave waveguide, 2 is a microwave transmission window, 3 is a plasma emission chamber (plasma generation chamber), 4D is a microwave shielding flange, 4B is a microwave shielding plate, 4C is a fixing screw, and 5 is a process. Gas inlet, 5A is process gas inlet, 5B is process gas inlet, 6 is processing chamber (reaction chamber), 7
Is an object to be processed.

The difference from the conventional example (2) is that in the microwave shielding flange 4D, the ring-shaped process gas inlet 5A
The boundary between the plasma emission chamber 3 and the plasma emission chamber 3 is partitioned, and the gas is blown into the plasma emission chamber 3 through the process gas introduction hole 5B provided on the circumference of the partition.

The microwave shielding flange 4D and the microwave shielding plate 4B are attached by fixing screws 4C so that they can be removed during cleaning. In the embodiment, four process gas introduction holes 5B are provided on the circumference, but more process gas introduction holes 5B may be provided at equal intervals on the circumference.

Next, a process using this device will be described. Example 1: Ashing with O ₂ + CF ₄ gas The ashing rate was measured with a structure as shown in FIG. 1 in which reactive reactive species are diffused and transported. Further, in order to confirm the effect of the microwave shielding flange of the embodiment, comparison was made with the conventional example (1) having no microwave shielding flange and the conventional example (2) having the microwave shielding flange.

The ashing conditions are as follows. O ₂ 900 SCCM CF ₄ 100 SCCM Gas pressure 1 Torr μ Wave power 1.5 KW Substrate temperature 25 ℃ As a result of ashing, the rate was as follows.

Example: 2.8 μm / min Conventional example (1): 0.7 μm / min Conventional example (2): 2.0 μm / min In other words, the example in which there is a microwave shielding flange and the amount of gas can be controlled is the most ashing. It was confirmed that can be speeded up.

Example 2: Operational stability of ashing with O ₂ + CF ₄ gas After etching was performed 400 times under the same conditions as for ashing, the ashing rate was measured under the same conditions as in Example 1.

As a result, the ashing rate was as follows. Example: 2.4 μm / min Conventional example (1): 0.3 μm / min Conventional example (2): 2.0 μm / min After the ashing treatment was performed 400 times, the ashing rate was measured under the same conditions as in Example 1. .

As a result, the ashing rate was as follows. Example: 2.3 μm / min Conventional example (1): 0.2 μm / min Conventional example (2): 1.3 μm / min In all cases, the example obtains a stable ashing rate with the smallest variation in ashing rate. Was given.

Example 3 Oxide Film Etching with O ₂ + CF ₄ Gas Etching conditions are as follows. O ₂ 900 SCCM CF ₄ 100 SCCM Gas pressure 1 Torr μ Wave power 1.5 KW Substrate temperature 135 ℃ As a result, the etching rate is as follows.

Example: 1400 Å / min Conventional Example (2): 900 Å / min The Example has a higher etching rate.

The results of Examples 1 to 3 show that the present invention is effective for speeding up and stabilizing the processing. Further, in the device of the conventional example (2), it was necessary to periodically clean the plasma emission chamber that was degenerated by plasma, but in the device of the example, the microwave shielding flange screwed in the plasma emission chamber is replaced. Only by doing so, the same effect as cleaning was obtained and the repairability of the device was improved.

[0027]

According to the present invention, the processing rate is improved by providing a microwave shielding flange having a plurality of gas introduction ports arranged on the outer circumference so that the gas introduced into the plasma emission chamber can be controlled. And stabilization can be achieved,
Further, abnormal discharge of plasma can be suppressed and the repairability of the device can be improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment.

FIG. 2 is an explanatory diagram of a conventional example (1).

FIG. 3 is an explanatory diagram of a conventional example (2).

[Explanation of symbols]

 1 microwave waveguide 2 microwave transmission window 3 plasma emission chamber 4D microwave shielding flange 4B microwave shielding plate 4C fixing screw 5 process gas inlet 5A process gas inlet 5B process gas inlet 6 treatment chamber 7 object to be treated

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H01L 21/302 H

Claims (3)

[Claims] 1. A plasma light emitting chamber for introducing a microwave through a microwave transmitting window and a process gas through a gas inlet to generate a gas plasma, and a processing chamber thereunder for processing an object to be processed, Between the plasma emission chamber and the processing chamber, a transport hole for downflowing reactive species from the plasma emission chamber is provided in the center, and a microwave blocking flange is provided below the transport hole with a gap. A microwave shielding flange having a shield plate provided therein, the microwave shielding flange comprising a process gas introducing portion formed of a cavity provided in a ring shape around the microwave shielding flange, and the plasma emission chamber from the process gas introducing portion. And a plurality of process gas introduction holes communicating with the semiconductor processing device. 2. The semiconductor processing apparatus according to claim 1, wherein the microwave blocking flange is screwed to the plasma emission chamber. 3. A semiconductor processing method, wherein a semiconductor substrate is processed by using the apparatus according to claim 1.