JPH0794486A - Etching apparatus of semiconductor - Google Patents

Abstract

PURPOSE:To ensure correct detection of an etching treatment end point corresponding to an etching rate (Angstrom /sec) by an end point detector mounted on an etching apparatus of a semiconductor. CONSTITUTION:A light-sensing part 5 of an end point detector which senses light emitted from the surface of a wafer 1 is fitted to a fixing part 3 of a wafer holding part 11 comprising a wafer 1, a wafer retainer 2, a chuck 6 and the fixing part 3 fitted with a motor 7 for rotating the chuck. Even when the wafer holding part 11 is tilted in the direction of an angle of elevation or depression to a fitting part 4 with an etching rate changed and set, the light-sensing part 5 moves in linkage therewith, in this constitution, so that the relative position thereof to the wafer 1 may not change.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an etching apparatus used for manufacturing semiconductors, and more particularly to an etching apparatus having an improved mounting position of a light receiving portion of an end point detector (end point detector) of etching processing.

[0002]

2. Description of the Related Art An etching apparatus is a lithium niobate (LiNbO ₃ ) or lithium tantalate (LiTa).
It is also used in the production of surface acoustic wave (SAW) devices that form a fine electrode pattern on a piezoelectric substrate such as O ₃ ).
An end point detector for detecting the end point of the etching process is attached to this etching apparatus.

Next, a method for detecting an end point will be described. In most dry etching processes, such as thin films that are etched when irradiated with an ion beam,
The light emission phenomenon of different wavelengths accompanies the material of the object to be processed.
At the end point where the etching process progresses and the thin film of the layer to be etched disappears completely, the light of different wavelengths in the next layer appears, and a large change in emission intensity appears. Therefore, by continuously monitoring the emission intensity of light having a wavelength corresponding to the layer to be etched, the endpoint of the etching process can be easily detected. For example, if the emission wavelength from the etching layer is selected and the emission intensity is monitored, the endpoint can be detected by a sharp decrease in the emission intensity.
Also, if the wavelength is monitored in accordance with the layer next to the layer to be etched, it can be detected by the rapid increase in the emission intensity.

2A and 2B are explanatory views of a wafer holding portion of a conventional etching apparatus. FIG. 2B is a partial sectional plan view and FIG. 2A is a partial front view seen from the ion beam irradiation side. In the figure, 1 is an object to be processed such as a wafer, 2 is a wafer retainer,
6 is a chuck for adsorbing the wafer 1, 7 is a motor for rotating the chuck 6, 3 is a fixing portion for fixing the chuck 6 and the motor 7, and 4 is an attachment in which the fixing portion 3 is rotatably attached in an elevation angle or a dip angle direction. Parts 5 are light receiving parts for detecting the light emission of the wafer 1, and are fixed to the mounting part 4. Reference numeral 8 is an endpoint controller, and 9 is a spectroscope, which is connected to the light receiving section 5 by an optical fiber cable and selects a single light having a wavelength corresponding to the material of the etching layer from the light detected by the light receiving section 5. Input to the controller 8.

Next, this operation will be described. During the etching by the ion beam, the chuck 6 and the wafer 1 are rotated by the motor 7, the light receiving unit 5 detects the light emission from the wafer 1, and the end point controller 8 transmits the light of a specific wavelength through the spectroscope 9. The etching equipment is controlled while monitoring the strength of the etching. FIG. 3 is a schematic side view with respect to FIG. 2B, and 11 is a wafer holder.
1, 2, 3, and 6, 7 are represented as a whole. Reference numeral 12 is a motor for changing the angle of the wafer holder 11 in the dip direction (θ) or the elevation direction, and 13 is a chamber. The wafer holding unit 11 can be arbitrarily changed in angle with respect to the irradiation direction of the ion beam by the motor 12.

The reason why the angle needs to be changed will be described below. The angle change is not basically performed during etching, but is set in advance when the wafer 1 is set on the chuck 6. The angle θ is determined according to the material of the layer to be etched and the etching rate (Å / sec), and is set each time depending on the work purpose.

[0007]

However, at the mounting position of the light receiving portion 5 of the end point detector in the above-mentioned conventional etching apparatus, when the angle of the wafer holding portion 11 is changed depending on the type of thin film and the process, the mounting portion 4 is mounted. Since the wafer holding unit 11 and the wafer holding unit 11 are not interlocked with each other, the relative position between the light receiving unit 5 for detecting light emission and the wafer 1 is changed, and the aim of the light receiving unit 5 is deviated from the wafer 1. Therefore, the amount of received light is reduced and the endpoint detection Has the disadvantage that it is not done correctly.

An object of the present invention is to solve the above problems and to provide a semiconductor etching apparatus capable of accurately detecting the end point even if the angle of the wafer holder 11 is changed.

[0009]

In the etching apparatus of the present invention, the relative position between the light receiving portion of the endpoint detector and the object to be etched does not change even if the tilt angle of the object to be etched with respect to the ion beam irradiation direction changes. To
The gist of the invention is that it is interlocked with the wafer holder, and the structure is a wafer for holding the wafer to be etched by adjusting the inclination angle corresponding to the etching rate with respect to the irradiation direction of the ion beam. The holding unit and the light receiving unit detects the light emitted from the processing surface of the wafer while performing the etching process by irradiating the wafer with an ion beam, and monitors the emission intensity of the light to detect a large change in the emission intensity. In a semiconductor etching apparatus provided with an end point detector for detecting an end point of etching processing, the light receiving section is attached to the wafer holding section, and processing of a wafer under etching processing is performed even if an inclination angle of the wafer holding section is changed. It is characterized in that the relative position between the surface and the light receiving portion is not changed.

[0010]

FIG. 1 is an explanatory view showing an embodiment of the present invention,
In the figure, (B) is a partial cross-sectional plan view, and (A) is a partial front view seen from the ion beam irradiation side. In the figure, each reference numeral is the same as that in FIG. As shown in FIG. 1, the light receiving section 5 that detects the light from the wafer 1 is attached to the fixing section 3 that interlocks with the chuck 6. Therefore, even if the wafer holding unit 11 is set to be inclined in the direction of the elevation angle or the dip angle, it is possible to always receive the light emission of the same area of the wafer 1.

[0011]

As described in detail above, by carrying out the present invention, it is possible to always receive the light in the same area of the object to be etched even if the etching angle changes depending on the type of thin film or the process. Since the end point of the etching process can be accurately detected regardless of the angle, the practical effect is great.

[Brief description of drawings]

FIG. 1 is a partial sectional plan view and a partial front view showing an embodiment of the present invention.

FIG. 2 is a partial sectional plan view and a partial front view showing a conventional structure.

FIG. 3 is a schematic side view of an etching apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wafer 2 Wafer holder 3 Fixing part 4 Mounting part 5 Light receiving part 6 Chuck 7 Motor 8 Endpoint controller 9 Spectroscope 11 Wafer holding part 12 Motor 13 Chamber

Claims (1)

[Claims] 1. A wafer holding unit for holding a wafer to be etched by adjusting an inclination angle corresponding to an etching rate with respect to an irradiation direction of an ion beam, and an etching process by irradiating the wafer with the ion beam. And an end point detector that detects the light emitted from the processing surface of the wafer by the light receiving unit to monitor the emission intensity of the light and detect the end point of the etching process by a large change in the emission intensity. In a semiconductor etching apparatus, the light receiving section is attached to the wafer holding section so that the relative position between the processing surface of the wafer being etched and the light receiving section does not change even if the inclination angle of the wafer holding section changes. A semiconductor etching apparatus characterized by the above.