JP-7855794-B2 - Plasma processing apparatus and plasma processing method

Inventors

• 江藤 宗一郎
• 中元 茂
• 福地 功祐

Assignees

• 株式会社日立ハイテク

Dates

Publication Date

20260508

Application Date

20230914

Claims (9)

1. The processing chamber inside the vacuum container, A plasma processing apparatus comprising a sample stage located in the processing chamber on which a wafer to be processed is placed, A light irradiation unit having multiple irradiators that irradiate light at different positions toward the surface of a wafer placed on the sample stage, A light receiving unit that receives reflected light reflected by the wafer from the light irradiated from the plurality of irradiators, The system includes a processing amount detection unit that detects the amount of wafer being processed based on information obtained from reflected light received by the light receiving unit during the wafer processing, The processing amount detection unit determines which irradiator to use for light irradiation from among the plurality of irradiators based on the difference between information on each reflection position of the wafer to which light irradiated from each of the plurality of irradiators is reflected and information on the processing position of the wafer, and detects the processing amount of the wafer using the determined irradiator. Plasma processing equipment.
2. In the plasma processing apparatus according to claim 1, The processing amount detection unit selects an irradiator from among the plurality of irradiators in which the distance between the reflection position on the wafer where the light irradiated from the irradiator is reflected and the processing position on the wafer is closer than a preset distance, and uses the selected irradiator to detect the processing amount of the wafer. Plasma processing equipment.
3. In the plasma processing apparatus according to claim 2, The processing amount detection unit is, From among the plurality of irradiators, the irradiator that has the closest distance between the reflection position on the wafer where the irradiated light emitted from the irradiator is reflected and the processing position on the wafer is selected, and the amount of processing on the wafer is detected using the selected irradiator. Plasma processing equipment.
4. In the plasma processing apparatus according to claim 2, The processing amount detection unit is, Based on the coordinates of the processing position and the coordinates of the reflection position on the surface of the wafer, the distance between the reflection position and the processing position on the wafer is calculated. Plasma processing equipment.
5. In the plasma processing apparatus according to claim 1, The processing amount detection unit is, Based on the result of comparing the spectrum of the reflected light received by the light receiving unit with a preset reference spectrum, the irradiator used to detect the processing amount of the wafer is selected. Plasma processing equipment.
6. In the plasma processing apparatus according to claim 1, Each of the aforementioned irradiators is composed of a lens and an optical fiber. Plasma processing equipment.
7. In the plasma processing apparatus according to claim 1, Each of the irradiators has an LED light source. Plasma processing equipment.
8. The processing chamber inside the vacuum container, The processing chamber includes a sample stage on which the wafer to be processed is placed, A light irradiation unit having multiple irradiators that irradiate light at different positions toward the surface of a wafer placed on the sample stage, A plasma processing method using a plasma processing apparatus having a light receiving unit that receives reflected light reflected by the wafer from light irradiated from the plurality of irradiators, Based on the difference between the information of each reflection position on the wafer to which light irradiated from each of the plurality of irradiators is reflected and the information of the processing position on the wafer, the irradiator to irradiate the wafer is determined from among the plurality of irradiators, the amount of processing on the wafer is detected using the determined irradiator, and the processing of the wafer is controlled based on the detected amount of processing. Plasma treatment method.
9. In the plasma treatment method according to claim 8, From among the plurality of irradiators, select an irradiator in which the distance between the reflection position on the wafer where the light irradiated from the irradiator is reflected and the processing position on the wafer is closer than a preset distance, and use the selected irradiator to detect the amount of wafer processed. Plasma treatment method.

Description

The technology disclosed herein relates to a plasma processing apparatus and a plasma processing method using the same. Semiconductor devices, for example, have various components and interconnecting wiring on the surface of a wafer. Such semiconductor devices are formed by repeatedly depositing films of various materials such as conductors, semiconductors, and insulators, and removing unwanted portions. Plasma-based dry etching is widely used as a process for removing unwanted parts. In plasma etching, a gas introduced into the processing chamber of the etching apparatus is converted into plasma using a high-frequency power supply, and etching is performed by exposing the wafer to the plasma-converted gas. Anisotropic and isotropic etching can be performed by sputtering with ions in a plasma or by chemical reactions with radicals. By using these etching methods appropriately, various structural components and wiring can be formed on the surface of a wafer. If the processed wafer shape obtained by plasma etching differs from the design, the various components formed will not be able to perform their intended function. Therefore, numerous process monitoring technologies have been proposed to monitor and stabilize the wafer etching process. For example, a process monitor that measures the thickness of a film deposited on a wafer or the depth of grooves and holes formed on a wafer by measuring the reflected light from the wafer during etching is also called a film thickness/depth monitor and is used for determining the end point of the etching process. Hereafter, the term "film thickness/depth monitor" will be abbreviated to "film thickness monitor." Patent Document 1 describes a method for improving processing accuracy using a film thickness monitor. More specifically, Patent Document 1 describes a method in which a film thickness measuring device equivalent to a thick film monitor using plasma light as a light source is used to detect the timing just before the film to be processed is completely removed, thereby terminating the etching process, and then the etching process is performed by switching to conditions that highly selectively etch the parts to be processed and the parts not to be processed. Furthermore, Patent Document 2 describes a technique for improving the accuracy of measuring film thickness and depth using a film thickness monitor. More specifically, Patent Document 2 describes how using an external light source instead of plasma light as the light source irradiated onto the wafer reduces fluctuations in the light source, enabling highly accurate measurement of film thickness and depth. Japanese Patent Publication No. 2006-119145Special Publication No. 2004-507070 This figure shows the overall configuration of the plasma processing apparatus according to Embodiment 1.This figure shows the schematic configuration of a wafer processing machine according to Embodiment 1.This diagram schematically shows the configuration of the optical system according to Embodiment 1.This figure schematically shows an example of a wafer pattern layout in Embodiment 1.This diagram shows the functional block of the processing amount calculation unit according to Embodiment 1.This figure shows the spectrum of reflected light from the electronic circuit portion of the wafer in Embodiment 1.This figure shows the spectrum of reflected light from the peripheral portion of the wafer in Embodiment 1.This diagram schematically shows the positional relationship between the light irradiation unit and the light receiving unit according to Embodiment 2.This figure shows the wafer processing position and monitoring position in Embodiment 2.This diagram schematically shows the positional relationship between the light irradiation unit and the light receiving unit according to Embodiment 3.This figure shows an example of the wafer processing position and monitoring position in Embodiment 3.This figure shows the spectrum of reflected light obtained by test irradiation in Embodiment 4.This figure shows an example of the calculation result of the error value between the reflected light spectrum at each monitor position and the reference spectrum in Embodiment 6. The embodiments of the technology described herein will be described in detail below with reference to the drawings. In the drawings, the same parts will be denoted by the same reference numerals in principle, and repeated descriptions will be omitted. In the drawings, the representation of components may be schematic in terms of width, thickness, shape, etc., of each part, in order to facilitate understanding of the invention, but this is merely an example and does not limit the interpretation of this disclosure. (Embodiment 1) Figure 1 is a diagram showing the overall configuration of the plasma processing apparatus according to Embodiment 1. Figure 2 is a diagram showing the schematic configuration of the wafer processing apparatus according to Embodiment 1. Figure 3 is