CN112635279B

CN112635279B - PFG electronic spraying system

Info

Publication number: CN112635279B
Application number: CN202011463297.7A
Authority: CN
Inventors: 马富林; 郑刚; 曹志伟
Original assignee: Hua Hong Semiconductor Wuxi Co Ltd
Current assignee: Hua Hong Semiconductor Wuxi Co Ltd
Priority date: 2020-12-14
Filing date: 2020-12-14
Publication date: 2022-06-07
Anticipated expiration: 2040-12-14
Also published as: CN112635279A

Abstract

The application discloses PFG electronic spray system relates to the semiconductor manufacturing field. The PFG electronic spraying system comprises an electronic scanning assembly and a PFG cavity; the electronic scanning assembly comprises an electron generator and an electronic scanner, the electron generator is positioned above the PFG cavity, the electronic scanner is positioned below an emission port of the electron generator, and the electronic scanner is used for scanning electrons emitted by the electron generator and enabling the electrons to be uniformly sprayed; the electronic scanner is connected with variable frequency voltage; the electronic scanner is composed of 2 secondary plates, each secondary plate is formed by connecting an upper plate and a lower plate, the upper plate is vertically arranged below the electronic generator, and the included angle between the lower plate and the upper plate is larger than 90 degrees; the upper plates of the 2 secondary plates are parallel, and the distance between the lower plates of the 2 secondary plates is larger than that between the upper plates; the problem that the uniformity of ion implantation is poor easily caused by an electronic spraying system of the conventional high-current ion implanter is solved; the effect of improving the uniformity of ion implantation is achieved.

Description

PFG electronic spraying system

Technical Field

The application relates to the field of semiconductor manufacturing, in particular to a PFG electronic spraying system.

Background

In the field of semiconductor manufacturing, an ion implantation process plays an important role in the production process of an integrated circuit device, and the ion implantation process is mainly applied to isolation between the device and a substrate, short channel effect, source and drain doping, polycrystalline layer passivation, threshold voltage adjustment and the like.

The ion implantation process is realized by an ion implantation machine, and the ion implantation machine generally comprises an ion source, an extraction electrode, an ion analyzer, an accelerating tube, a process chamber and the like. Ions are generated by an ion source, the ions are accelerated to form an ion beam current, and the ion beam current is utilized to realize ion implantation on a wafer placed in a process chamber.

Taking a high current ion implantation machine provided by a semiconductor supplier AMAT as an example, an ion beam is mainly used for bombarding a wafer, because the ion beam bombards the wafer, a large amount of positive charges are accumulated on the surface of the wafer, and in order to prevent the positive charges from charging the wafer, a plasma electron spraying system is arranged at the tail end of the ion implantation machine. The existing high current ion implantation machine has 2 electron generators, which are located above the ion beam and PFG (electrostatic neutralization and beam control) cavity, and electrons generated in the electron generators are attracted out under the action of the traction force of the positive potential of the ion beam to neutralize the positive charge in the ion beam. Because the electron speed that electron generator's emission hole jetted out is less, most electron concentrates on under the electron generator export, and only when being close to the ion beam, the electron just can scatter the parcel ion beam, leads to ion implantation inhomogeneous easily.

Disclosure of Invention

In order to solve the problems in the related art, the present application provides a PFG electronic shower system. The technical scheme is as follows:

in one aspect, an embodiment of the present application provides a PFG electronic spray system, which includes an electronic scanning assembly and a PFG cavity;

the electronic scanning assembly comprises an electron generator and an electronic scanner, the electron generator is positioned above the PFG cavity, the electronic scanner is positioned below an emission port of the electron generator, and the electronic scanner is used for scanning electrons emitted by the electron generator and enabling the electrons to be uniformly sprayed;

the electronic scanner is connected with variable frequency voltage;

the electronic scanner is composed of 2 secondary plates, each secondary plate is formed by connecting an upper plate and a lower plate, the upper plate is vertically arranged below the electronic generator, and the included angle between the lower plate and the upper plate is larger than 90 degrees;

in the electronic scanner, the upper plates of the 2 secondary plates are parallel, and the distance between the lower plates of the 2 secondary plates is larger than that between the upper plates;

the upper plates of the 2 secondary plates are respectively positioned at two sides of the emission port of the electron generator.

Optionally, the amplitude of the variable frequency voltage is ± 5KV, and the frequency of the variable frequency voltage is 1 KHz.

Optionally, the sum of the length of the upper plate and the length of the lower plate in each secondary plate is 10 cm;

the distance between the upper plates in the 2 secondary plates was 5 cm.

Optionally, at least 2 electronic scanning assemblies are included.

Optionally, the system further comprises a graphite plate, and a plurality of current sensors are arranged in the graphite plate;

the graphite plate is used for detecting whether electrons scanned by the electronic scanner are uniformly sprayed or not;

before ion implantation, the graphite plate is moved from the accommodating position to the position below the electronic scanner; when ion implantation is performed, the graphite plate is retracted to a storage position, which is a region other than the electronic scanner.

Optionally, the plurality of current sensors are uniformly arranged inside the graphite plate.

Optionally, the number of current sensors in the graphite plate is 7 or 13.

Optionally, the current sensor is wrapped with a graphite material.

Optionally, each secondary plate is wrapped with a graphite material.

The technical scheme at least comprises the following advantages:

the FG electronic spraying system provided by the embodiment of the application comprises an electronic scanning assembly and a PFG cavity; the electronic scanning assembly comprises an electron generator and an electronic scanner, the electron generator is positioned above the PFG cavity, the electronic scanner is positioned below an emission port of the electron generator, and the electronic scanner is used for scanning electrons emitted by the electron generator and enabling the electrons to be uniformly sprayed; the electronic scanner is connected with variable frequency voltage; the electronic scanner is composed of 2 secondary plates, each secondary plate is formed by connecting an upper plate and a lower plate, the upper plate is vertically arranged below the electronic generator, and the included angle between the lower plate and the upper plate is larger than 90 degrees; in the electronic scanner, the upper plates of the 2 secondary plates are parallel, and the distance between the lower plates of the 2 secondary plates is larger than that between the upper plates; the upper plates of the 2 secondary plates are respectively positioned at two sides of an emission port of the electron generator; the problem that the uniformity of ion implantation is poor easily caused by an electronic spraying system of the conventional high-current ion implanter is solved; the effect of improving the uniformity of ion implantation is achieved.

Drawings

In order to more clearly illustrate the detailed description of the present application or the technical solutions in the prior art, the drawings needed to be used in the detailed description of the present application or the prior art description will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a schematic diagram of a PFG electronic spray system provided in an embodiment of the present application;

FIG. 2 is a schematic view of an electronic scanning assembly provided in an embodiment of the present application;

fig. 3 is a graph of voltage versus time corresponding to a variable frequency voltage provided in an embodiment of the present application;

fig. 4 is a schematic working diagram of two electronic scanning assemblies in the PFG electronic spray system provided in the embodiment of the present application;

FIG. 5 is a schematic diagram of an electronic scanning assembly and a graphite plate in a PFG electronic spray system provided by an embodiment of the present application;

FIG. 6 is a schematic diagram of a preset curve provided by an embodiment of the present application;

fig. 7 is a schematic diagram of the operation of two electronic scanning assemblies in a conventional PFG electronic spray system.

Detailed Description

The technical solutions in the present application will be described clearly and completely with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; the connection can be mechanical connection or electrical connection; the two elements may be directly connected or indirectly connected through an intermediate medium, or may be communicated with each other inside the two elements, or may be wirelessly connected or wired connected. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

In addition, the technical features mentioned in the different embodiments of the present application described below may be combined with each other as long as they do not conflict with each other.

The embodiment of the application provides a PFG electronic spray system, and the system comprises an electronic scanning assembly and a PFG cavity.

As shown in fig. 1, the electronic scanning assembly includes an electron generator 11 and an electronic scanner 12. The electronic scanner 12 is located below the emission port of the electronic generator 11.

Electrons 14 generated by the electron generator 11 are ejected from an emission port of the electron generator.

The electron generator 11 is located above the PFG chamber 13. During ion implantation, an ion beam 15 passes through the PFG chamber 13.

The electronic scanner is connected with the variable frequency voltage.

The electron scanner 12 is used to scan the electrons 14 emitted from the electron generator 11 and make the electrons 14 uniformly sprayed. The uniformly sprayed 14 electrons uniformly envelop the passing ion beam 15 within the PFG chamber 13.

Since the ion beam 15 is uniformly wrapped by the electrons 14, the positive charges of the ion beam 15 can be better neutralized by the electrons 14, thereby improving the uniformity of ion implantation.

As shown in fig. 2, the electronic scanner 12 is composed of 2 diode plates, each of which is constituted by connecting an upper plate 121 and a lower plate 122, the upper plate 121 is vertically disposed below the electronic generator 11, and a jig between the lower plate 122 and the upper plate 121 is larger than 90 °.

The 2 diode boards composing the electronic scanner are symmetrical.

In the electronic scanner, the upper plates 121 of the 2 secondary plates are parallel, and the distance between the lower plates 122 of the 2 secondary plates is larger than the distance between the upper plates 121. As shown in fig. 2, the electronic scanner 12 is horn shaped.

The upper plates 121 of the 2 secondary plates are respectively located at both sides of the emission port of the electron generator 11.

The electrons ejected from the electron generator 11 pass through the electronic scanner, are scanned by the electronic scanner, and are uniformly sprayed downward.

The connection of the electronic scanner and the variable frequency voltage is realized by applying the variable frequency voltage on 2 secondary boards of the electronic scanner.

In one example, the electronic scanner is connected to a variable frequency voltage of + -5 KV, the variable frequency voltage has a frequency of 1KHz, and a voltage versus time graph of the variable frequency voltage is shown in FIG. 3.

In one example, the sum of the length L1 of the upper plate 121 and the length L2 of the lower plate 122 in each secondary plate is 10 cm; in an electronic scanner, the distance between the upper plates in the 2 diode boards was 5 cm.

Optionally, the distance between the emission port of the electron generator and each secondary plate below the emission port is the same.

In the PFG electronic shower system, at least 2 electronic scanning assemblies are included, each electronic scanning assembly including 1 electronic generator 11 and electronic scanner 12, as shown in fig. 4.

Optionally, to avoid contamination of the electronic scanner by metal, each secondary plate is wrapped with a graphite material.

The PFG electronic spray system provided in the embodiment of the present application further includes a graphite plate 21, and a plurality of current sensors 22 are provided in the graphite plate 21, as shown in fig. 5.

The graphite plate 21 loaded with the current sensor 22 is used to detect whether the electrons scanned by the electron scanner 12 are uniformly sprayed before ion implantation is performed on the silicon wafer.

Detecting the current formed by the sprayed electrons through a current sensor, and when a current curve is detected to be consistent with a preset curve, determining that the electrons scanned by an electronic scanner are uniformly sprayed, so that ion implantation can be carried out on the silicon wafer; when the current curve is detected to be inconsistent with the preset curve, it is indicated that the electrons scanned by the electronic scanner are not uniformly sprayed, and the machine debugging is required to be carried out again.

In one example, the predetermined curve is shown in fig. 6, and x1 represents a position on the graphite sheet.

The PFG electronic spraying system is provided with a containing position, and the containing position is used for containing the graphite plate; the housing position is in a region other than the electronic scanner.

When the situation that whether the electrons scanned by the electronic scanner are uniformly sprayed or not does not need to be detected, the graphite plate is stored at a storage position; when it is necessary to detect whether the electrons scanned by the electronic scanner are uniformly sprayed before ion implantation, the graphite plate 21 is moved from the storage position to a position below the electronic scanner; when ion implantation is performed, the graphite plate is retracted from below the electronic scanner to the storage position.

If the PFG system includes at least 2 electronic scanning assemblies, the graphite plate is located below the at least 2 electronic scanning assemblies when detecting whether the electrons scanned by the electronic scanner are uniformly sprayed.

A plurality of current sensor evenly sets up the inside at the graphite cake.

In one example, the number of current sensors in the graphite plate is 7; in another example, the number of current sensors is 13.

In order to avoid contamination of the current sensor by metal, the current sensor is wrapped with a graphite material.

Taking the conventional PFG electronic spraying system including 2 electron generators as an example, as shown in fig. 7, electrons 14 emitted from the electron generator 11 are concentrated under the outlet of the electron generator 11, and when the electrons approach the ion beam 15, the electrons are scattered, so that the neutralization effect on positive charges carried by the ion beam 15 is not good, and the problem of non-uniform ion implantation is easily caused.

Taking the PFG electronic spray system provided by the embodiment of the present application as an example, as shown in fig. 4, the electrons 14 ejected by the electron generator are uniformly dispersed after being scanned by the electronic scanner 12, and the uniformly dispersed electrons are scattered on the ion beam 15, so that the degree of neutralization of positive charges carried by the ion beam 15 can be improved, and the problem that the conventional electronic spray system of a high current ion implanter is likely to cause poor uniformity of ion implantation is solved; the effect of improving the uniformity of ion implantation is achieved.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications of this invention are intended to be covered by the scope of the invention as expressed herein.

Claims

1. A PFG electronic spraying system is characterized by comprising an electronic scanning assembly and a PFG cavity;

the electronic scanner is connected with variable frequency voltage;

and the upper plates of the 2 secondary plates are respectively positioned at two sides of the emission port of the electron generator.

2. The PFG electronic sprinkler system of claim 1, wherein said variable frequency voltage has an amplitude of ± 5KV and a frequency of 1 KHz.

3. The PFG electronic spray system of claim 1, wherein the sum of the length of the upper plate and the length of the lower plate in each secondary plate is 10 cm;

the distance between the upper plates in the 2 secondary plates was 5 cm.

4. The PFG electronic spray system of claim 1, comprising at least 2 electronic scanning assemblies.

5. The PFG electronic spray system of any of claims 1 to 4, further comprising a graphite plate, wherein a plurality of current sensors are disposed in said graphite plate;

the graphite plate is used for detecting whether the electrons scanned by the electronic scanner are uniformly sprayed or not;

prior to ion implantation, the graphite plate is moved from a stowed position to below the electronic scanner; when ion implantation is performed, the graphite plate is retracted to the storage position, which is a region other than the electronic scanner.

6. The PFG electronic spray system of claim 5, wherein said plurality of current sensors are uniformly disposed inside said graphite plate.

7. The PFG electronic spray system of claim 5, wherein the number of current sensors in said graphite plate is 7 or 13.

8. The PFG electronic spray system of claim 5, wherein said current sensor is wrapped by a graphite material.

9. The PFG electronic spray system of claim 1, wherein each secondary plate is wrapped with a graphite material.