CN109633734B - Device and method for detecting neutron content in ion implantation cavity - Google Patents

Abstract

The invention discloses a device for detecting neutron content in an ion implantation cavity, which comprises an ion injection cavity, an ion source, a data collection module and a processing module. A substrate coated with photoresist is placed in the ion injection cavity, and the ion implantation cavity The source performs ion implantation on the photoresist in the substrate, and the neutrons generated during the ion implantation interact with the atomic nuclei of C, H, and O elements in the photoresist to generate gamma rays. The data collection module is used for The intensity of the gamma rays in the ion implantation chamber is measured, and the intensity is transmitted to the processing module, and the processing module calculates the content of neutrons generated during the ion implantation process according to the intensity of the gamma rays. The present invention provides a device and method for detecting neutron content in an ion implantation chamber. By measuring the intensity of gamma rays, the neutron content generated during high-energy ion implantation can be measured.

Description

Device and method for detecting neutron content in ion implantation cavity

technical field

The invention relates to integrated circuit process design, in particular to a device and method for detecting neutron content in an ion implantation chamber.

Background technique

With the continuous development of semiconductor technology, the role of ion implantation technology in the manufacture of integrated circuits is becoming more and more important. Ion implanter is the key equipment in the pre-process of integrated circuit manufacturing. Ion implantation is a technology for doping the area near the semiconductor surface. Its purpose is to change the carrier concentration and conductivity type of the semiconductor. The best way to dope. The particle accelerator of the high-energy ion implanter mainly includes radio frequency acceleration and electrostatic acceleration. The ions are accelerated in the system and at the same time emit radiation that is harmful to the human body and the environment, such as radiation. Therefore, the x-rays of the implanter must be detected daily, but for ultra-high-energy implanters, it is necessary to generate 2-, 3-, and even 4-valent ions. In this process, neutrons will be generated while x-rays are produced. However, neutrons have no charge, so when they penetrate objects, there is no electron Coulomb force with the electrons outside the nucleus of the atom, so they can easily pass through the electron layer and directly hit the nucleus to cause a nuclear reaction, thus making the injection machine Some metal materials such as aluminum and lead are easily broken down, causing damage; at the same time, because the neutron itself is not charged, it will not cause ionization and other effects, and cannot produce direct observable effects, so it is difficult to use conventional means to detect .

Therefore, a reliable neutron detection method in the high-energy ion implanter must be adopted to prevent the system from causing harm to the surrounding staff and polluting the environment.

Contents of the invention

The object of the present invention is to provide a device and method for detecting the content of neutrons in the ion implantation chamber, by bombarding the photoresist with high-energy ions, wherein the neutrons interact with the nuclei of C, H, O and other elements in the photoresist A large number of γ-rays are generated, and by measuring the intensity of these γ-rays, the content of neutrons generated during high-energy ion implantation can be measured.

In order to achieve the above object, the present invention adopts the following technical solution: a device for detecting neutron content in an ion implantation chamber, including an ion implantation chamber, an ion source, a data collection module and a processing module, the ion source is used for The implantation chamber performs ion implantation, and the data collection module is connected to the ion implantation chamber, the processing module and the ion source at the same time;

A substrate coated with photoresist is placed in the ion implantation chamber, and the ion source emits an ion beam to perform ion implantation on the photoresist in the substrate. The neutrons generated in the ion implantation process are mixed with the photoresist The nuclei of C, H, and O elements interact to generate γ-rays, and the data collection module is used to measure the intensity of γ-rays in the ion implantation cavity, and transmit the intensity of γ-rays to the processing module, and the processing The module calculates the neutron content produced in the ion implantation process according to the intensity of the γ-ray.

Further, the thickness of the photoresist is 6-10 microns.

Further, when the ion source performs ion implantation on the photoresist, the energy of the ion beam used is greater than 3 MeV.

A method for detecting neutron content in an ion implantation cavity provided by the present invention comprises the following steps:

S01: coating a layer of photoresist on the substrate, and putting the substrate into the ion implantation chamber;

S02: Using an ion source to perform ion implantation on the photoresist on the substrate surface in the ion implantation chamber, the neutrons generated during the ion implantation process interact with the nuclei of C, H, and O elements in the photoresist to generate γ-rays ;

S03: Use the data collection module to measure the intensity of the γ-ray in the ion implantation chamber, and transmit the intensity to the processing module;

S04: The processing module calculates the content of neutrons generated during the ion implantation process according to the intensity of the above-mentioned γ-rays.

Further, the intensity of the gamma rays is less than or equal to 0.6uSv/h.

Further, in the step S02, the energy of the ion beam used by the ion source to implant the photoresist on the surface of the substrate in the ion implantation chamber is greater than 3 MeV.

Further, the thickness of the photoresist is 6-10 microns.

The beneficial effects of the present invention are: the present invention uses a large number of particles bombarding the photoresist during the high-energy ion implantation process, wherein neutrons have a large absorption coefficient for elements such as C, H, and O, while protons and other particles do not absorb, neutrons and When the nuclei of C, H, O and other elements interact, inelastic scattering will occur and a large number of γ-rays will be generated. These γ-rays have high energy and produce large cross-sections, which are easy to measure, and their intensity is proportional to the content of C, H, and O. Proportional. By measuring the intensity of these γ-rays, the content of neutrons generated during high-energy ion implantation can be measured. The invention solves the problem that other methods cannot measure the neutrons produced by high-energy ion implantation, and the device has simple structure, simple components of the measuring system and low cost.

Description of drawings

Accompanying drawing 1 is a schematic structural diagram of a device for detecting neutron content in an ion implantation chamber according to the present invention.

In the figure: 100 substrate, 102 photoresist, 200 ion implantation chamber.

Detailed ways

In order to make the purpose, technical solution and advantages of the present invention clearer, the specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings.

As shown in Figure 1, a device for detecting neutron content in an ion implantation chamber provided by the present invention includes an ion implantation chamber 200, an ion source, a data collection module and a processing module, and the ion source is used to perform ion implantation chamber 200 For ion implantation, the data collection module is connected to the ion implantation chamber and the processing module at the same time. Wherein, the substrate may be a silicon substrate, and the photoresist layer coated on the silicon substrate has a thickness of 6-10 microns; the energy of the ion beam used by the ion source for ion implantation on the photoresist is greater than 3 MeV.

A substrate 100 coated with a photoresist 101 is placed in the ion implantation chamber 200, and the ion source emits ion beams to perform ion implantation on the photoresist 101 in the substrate. The neutrons generated in the ion implantation process and the C, The nuclei of H and O elements interact to generate γ-rays. The data collection module is used to measure the intensity of γ-rays in the ion implantation cavity, and transmits the intensity to the processing module. The processing module calculates the ion implantation process according to the intensity of γ-rays. The neutron content produced.

Among them, neutrons have a large absorption coefficient for elements such as C, H, and O, while particles such as protons do not absorb them. When neutrons interact with the nuclei of elements such as C, H, and O, inelastic scattering will occur, resulting in a large amount of γ Rays, these γ-rays have high energy, produce larger cross-sections, are easy to measure, and their intensity is proportional to the content of C, H, and O. The intensity of the gamma-ray measured by the data collection module in the present invention comprises the intensity of the gamma-ray, because this intensity is proportional to C, H, the content of O and the content of neutrons, the processing module can calculate the ion according to the intensity of the gamma-ray The content of neutrons in the injected cavity.

A method for detecting neutron content in an ion implantation cavity provided by the present invention comprises the following steps:

S01: Coating a layer of photoresist on the substrate, and putting the substrate into the ion implantation chamber. Wherein, the substrate may be a silicon substrate, and the photoresist layer coated on the silicon substrate has a thickness of 6-10 microns.

S02: Use an ion source to perform ion implantation on the photoresist on the surface of the substrate in the ion implantation chamber. The neutrons generated during the ion implantation interact with the nuclei of C, H, and O elements in the photoresist to generate γ-rays. Among them, the energy of the ion beam used by the ion source for ion implantation of the photoresist is greater than 3MeV, and the energy of the γ-ray is high, resulting in a large cross-section, which is easy to measure, and the intensity is proportional to the content of C, H, and O.

S03: Use the data collection module to measure the intensity of the γ-ray in the ion implantation chamber, and transmit the intensity to the processing module.

The intensity of the measured γ-ray in the present invention is less than or equal to 0.6uSv/h, when the intensity of the γ-ray is greater than this value, it indicates that the injection machine has a problem, and the SEMI standard has not been met, and it needs to be overhauled and then re-examined to see if it can be used standard.

Specifically, in the ion implantation process, a set threshold is determined in advance, and when the intensity of the gamma rays measured by the data collection module is greater than or equal to the set threshold, the ion source stops ion implantation, and the range of the set threshold is 0.4-0.6uSv /h. When the intensity of the measured γ-ray is greater than or equal to the set threshold, the receipt collection module sends an alarm signal or a stop signal, so that the ion source stops the implantation work.

S04: The processing module calculates the content of neutrons generated during the ion implantation process according to the intensity of the above-mentioned γ-rays. Wherein, since the intensity of the γ-ray is proportional to the content of C, H, O and the content of the neutron, the processing module can calculate the content of the neutron in the ion implantation cavity according to the intensity of the γ-ray.

The present invention utilizes that during the high-energy ion implantation process, a large number of particles bombard the photoresist, wherein neutrons have a large absorption coefficient for elements such as C, H, and O, while particles such as protons do not absorb, neutrons and elements such as C, H, and O When the atomic nuclei interact with each other, inelastic scattering will occur, and a large number of γ-rays will be generated. These γ-rays have high energy, large cross-section, easy to measure, and the intensity is proportional to the content of C, H, and O. By measuring the intensity of these γ-rays, the content of neutrons generated during high-energy ion implantation can be measured. The invention solves the problem that other methods cannot measure the neutrons produced by high-energy ion implantation, and the device has simple structure, simple components of the measuring system and low cost.

The above are only preferred embodiments of the present invention, and the embodiments are not intended to limit the scope of patent protection of the present invention, so all equivalent structural changes made by using the description and drawings of the present invention should be included in the same reason Within the protection scope of the appended claims of the present invention.

Claims (7)

1. The device for detecting the neutron content in the ion implantation cavity is characterized by comprising an ion implantation cavity, an ion source, a data collection module and a processing module, wherein the ion source is used for carrying out ion implantation on the ion implantation cavity, and the data collection module is simultaneously connected with the ion implantation cavity and the ion source;

the ion implantation device comprises an ion implantation cavity, an ion source, a data collection module and a processing module, wherein a substrate coated with photoresist on the surface is placed in the ion implantation cavity, the ion source emits ion beams to implant ions into the photoresist in the substrate, neutrons generated in the ion implantation process interact with atomic nuclei of C, H, O element in the photoresist to generate gamma rays, the data collection module is used for measuring the intensity of the gamma rays in the ion implantation cavity and transmitting the intensity of the gamma rays to the processing module, and the processing module calculates the content of the neutrons generated in the ion implantation process according to the intensity of the gamma rays.

2. The apparatus of claim 1, wherein the photoresist has a thickness of 6-10 microns.

3. The apparatus of claim 1, wherein the ion source is configured to ion implant the photoresist using an ion beam having an energy greater than 3MeV.

4. A method for detecting the neutron content in an ion implantation chamber is characterized by comprising the following steps:

s01: coating a layer of photoresist on a substrate, and putting the substrate into an ion implantation cavity;

s02: ion implantation is carried out on the photoresist on the surface of the substrate in the ion implantation cavity by using an ion source, neutrons generated in the ion implantation process interact with atomic nuclei of C, H, O elements in the photoresist to generate gamma rays;

s03: measuring the intensity of gamma-rays in the ion implantation chamber by using a data collection module, and transmitting the intensity to a processing module;

s04: and the processing module calculates the neutron content generated in the ion implantation process according to the intensity of the gamma rays.

5. The method for detecting the neutron content in the ion implantation chamber according to claim 4, wherein the intensity of said γ -ray is less than or equal to 0.6uSv/h.

6. The method for detecting the neutron content in the ion implantation chamber according to claim 4, wherein the energy of the ion beam used by the ion source for ion implantation of the photoresist on the surface of the substrate in the ion implantation chamber in the step S02 is greater than 3MeV.

7. The method of detecting the neutron content in an ion implantation chamber of claim 4, wherein the photoresist has a thickness of 6-10 microns.

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