CN-115597761-B - Pressure sensor

Abstract

The pressure sensor of the present invention reduces the effect of deposits on the diaphragm of the pressure sensor. The invention is provided with a movable electrode (104) formed in a movable region (102 a) of a diaphragm (102), and a fixed electrode (105) formed so as to face the movable electrode (104). The pressure of the diaphragm (102) is in an inert state. The inert pressure receiving surface of the diaphragm (102) is not likely to adsorb molecules of the measurement target gas. The pressure-receiving surface of the diaphragm (102) can be made inert by a predetermined surface treatment. By means of the surface treatment, a layer is formed which renders the pressure-receiving surface of the membrane (102) inert, the presence of which renders the pressure-receiving surface of the membrane (102) inert.

Inventors

• SOEDA MASARU
• ISHIHARA TAKUYA
• Hasune Masashi

Assignees

• 阿自倍尔株式会社

Dates

Publication Date

20260512

Application Date

20200617

Priority Date

20190702

Claims (7)

1. 1. A pressure sensor, comprising: A diaphragm capable of being displaced and receiving the pressure of the measurement object with a pressure receiving surface, and A measuring unit for measuring a displacement of the diaphragm, The pressure receiving surface of the membrane is chemically inert by being formed with a self-organized monolayer.
2. 2. The pressure sensor of claim 1, wherein the pressure sensor is configured to, The self-organized monolayer is composed of a plurality of molecular chains with consistent orientation and end capping atoms respectively end capped on the plurality of molecular chains.
3. 3. A pressure sensor according to claim 1 or 2, characterized in that, The self-organized monolayer is composed of aligned nanotubes having a uniform alignment property.
4. 4. A pressure sensor according to claim 1 or 2, characterized in that, The self-organized monolayer is composed of any one of a thiol system, a silane system, or an acetic acid system.
5. 5. A pressure sensor according to claim 1 or 2, characterized in that, The self-organized monolayer is targeted at a pressure-receiving surface exposed to a gas to be measured.
6. 6. A pressure sensor according to claim 1 or 2, characterized in that, The self-organized monolayer can be formed by surface treatment after the pressure sensor is fabricated.
7. 7. A pressure sensor according to claim 1 or 2, characterized in that, The self-organized monolayer can be formed by surface treatment of the pressure sensor that has been used.

Description

Pressure sensor The present application is a divisional application of the following application, The application date of the original application is 17 days of 6 months in 2020, The application number of the original application is 202010553359.7, The name of the original application is a pressure sensor. Technical Field The present invention relates to a pressure sensor. Background For example, pressure sensors that output a pressure value in accordance with the deflection, i.e., displacement, of a diaphragm subjected to pressure are widely used in industrial applications including semiconductor devices. Various film forming apparatuses and dry etching apparatuses based on vapor deposition are used for manufacturing semiconductor devices. In such a manufacturing apparatus, in order to form a thin film having a unit thickness of nm, it is important to accurately control the pressure in the process chamber, the partial pressure of the process gas, and the like, and to accurately measure the pressure. To achieve such pressure measurement, a pressure sensor is used. In such a pressure sensor, corrosion resistance against gases used in the apparatus, such as a process gas, and resistance against by-products generated in a process, such as film formation, are required. In addition, in the film forming process, deposition occurs on the inner wall of the film forming chamber, the inner wall of the pipe, the inside of the vacuum pump, and the pressure receiving portion of the pressure sensor, that is, the portion through which the process gas such as the diaphragm passes, and various problems are caused. For example, atomic Layer Deposition (ALD) is superior to conventional Chemical Vapor Deposition (CVD) in terms of level difference coating property and film quality, and has been developed in recent years for forming gate insulating films and the like. The ALD is characterized in that the raw material gas is easily attached to various portions through which the raw material gas passes, and the above-described wasteful deposition is easily generated. When such useless deposition occurs on the diaphragm of the pressure sensor, the zero point shift, the change in pressure sensitivity, and the like are caused as is well known, and thus accurate measurement is hindered and the result of the process is greatly affected. In order to prevent the above-described wasteful deposition on the film, each portion is heated to, for example, about 200 ℃ during film forming operation or the like. Further, there is proposed a technique of preventing unwanted deposition on a diaphragm by complicating a path of a process gas reaching the diaphragm by a baffle plate or the like and capturing unwanted deposition on the way (refer to patent documents 1 to 3). There has also been proposed a technique in which a portion where the process gas reaches the diaphragm is set to be a peripheral portion of the diaphragm so as to avoid the center of the diaphragm where the influence of deposition is large (refer to patent documents 1, 2, 4, and 5). In addition, a diaphragm structure has been proposed in which the rigidity of the diaphragm is adjusted to cope with ALD and the deflection itself of the diaphragm is suppressed (see patent document 6). There has also been proposed a technique of forming the surface of a diaphragm as a structured surface such as a lattice-like mesh, and greatly reducing bending stress caused by a material of a measurement medium deposited on the diaphragm (refer to patent document 7). [ Prior Art literature ] [ Patent literature ] Japanese patent laid-open No. 2001-149946 Japanese patent application laid-open No. 2016-526153 Japanese patent application laid-open No. 2015-034786 Japanese patent application laid-open No. 2014-126504 (patent document 4) Japanese patent application laid-open No. 2014-109484 (patent document 5) Japanese patent application laid-open No. 2010-236949 (patent document 6) Japanese patent application laid-open No. 2009-524024 (patent document 7) Disclosure of Invention [ Problem to be solved by the invention ] However, uniformity of film thickness and quality is now further advanced, so that a high-precision process is required. In such a background, the related art described above may cause a minute amount of deposition on the diaphragm, and furthermore, the stress of the deposition on the diaphragm (film stress) is not completely eliminated, so that the decrease in the accuracy of pressure measurement caused by these problems cannot be ignored. The present invention has been made to solve the above-described problems, and an object of the present invention is to further reduce the influence of deposits on a diaphragm of a pressure sensor. [ Means for solving the problems ] The pressure sensor of the present invention comprises a diaphragm capable of being displaced and receiving a pressure of a measurement object with a pressure receiving surface, and a measurement unit for measuring displaceme