A method for measuring ion implantation dose

Abstract

A kind of ion implantation dose measurement method is used to measure the ion implantation dose after ion implantation device is completed to the object to be processed, the device includes alternating current high voltage electrode, direct current negative voltage electrode and porous electrode, the object to be processed is placed on the blocking medium of direct current negative voltage electrode towards porous electrode;Measurement method includes: obtaining the voltage value applied on direct current negative voltage electrode and the capacitance value between direct current negative voltage electrode and the upper surface charge layer after ion implantation of the object to be processed;According to voltage value and capacitance value, the charge amount of injection object to be processed is calculated;According to the charge amount, the ion implantation dose is determined.The present application calculates the ion implantation dose by the system steady-state parameters before and after ion implantation, without measuring the transient parameters in ion implantation process, solves the problem that traditional ion implantation measurement method needs real-time high-precision detection of injection current, the technical requirement is difficult, and the cost is high, can greatly reduce the application cost of ion implantation technology.

Description

Technical Field

[0001] This invention relates to the field of ion implantation technology, and in particular to a method for measuring ion implantation dosage. Background Technology

[0002] Ion implantation is a method of introducing a controlled number of impurity particles into the surface of a material to alter its electrical properties. Ion implantation has various applications, such as semiconductor doping, metal surface strengthening, and non-metallic material surface modification. This technology delivers a specific dose and energy of ions to the material surface. The implanted ions interact with atoms in the sample to form new phases, altering the morphology, phase composition, composition, and microstructure of the sample surface and near-surface layers. This significantly changes the material's physical, chemical, and mechanical properties and phase state, opening up possibilities for its future applications.

[0003] Currently, plasma immersion ion implantation technology mainly relies on a combination of various parameters, such as ion current density, implantation time, ion beam energy, angular distribution, and the area of ​​the implanted region, to measure the ion implantation dose. This method requires many parameters, high precision for each parameter, and complex calculations due to the interrelationships between these parameters, thus significantly increasing the application cost of ion implantation. Furthermore, the above ion implantation dose measurement methods are online or real-time measurements, and the ion implantation process itself can affect the calculation accuracy. Another feasible method for ion implantation dose measurement is to calculate the implantation dose offline based on the changes in the electrical steady-state of the treated material (i.e., the analyte) before and after ion implantation. Patent application CN202210887666.8 discloses a plasma material surface modification device and method, which is a plasma non-immersed ion implantation (PNII) technology. Summary of the Invention

[0004] To address the challenge of high requirements in existing ion implantation dose measurement technologies, this invention proposes an ion implantation dose measurement method that enables accurate measurement of ion implantation dose in a simple and low-cost manner.

[0005] The technical problem of this invention is solved by the following technical solution:

[0006] An ion implantation dose measurement method is provided for measuring the ion implantation dose after ion implantation of a workpiece by an ion implantation device. The ion implantation device includes an AC high-voltage electrode, a DC negative voltage electrode, and a porous ground electrode located between the AC high-voltage electrode and the DC negative voltage electrode. A plasma generation region is located between the AC high-voltage electrode and the porous ground electrode, and an ion implantation region is located between the porous ground electrode and the DC negative voltage electrode. A barrier medium is provided on the side of the DC negative voltage electrode facing the porous ground electrode, and the workpiece is placed on the barrier medium.

[0007] The measurement method includes the following steps:

[0008] The DC negative voltage value applied to the DC negative voltage electrode and the capacitance value between the DC negative voltage electrode and the charge layer on the upper surface of the treated material after ion implantation are obtained.

[0009] The amount of charge injected into the object being treated is calculated based on the DC negative voltage value and the capacitance value.

[0010] The ion implantation dose is determined based on the amount of charge injected into the object being treated.

[0011] In some embodiments, the calculation of the amount of charge injected into the object to be treated based on the DC negative voltage value and the capacitance value is performed according to the following formula:

[0012]

[0013] Among them, Q 注入 ε represents the amount of charge injected into the object being treated. r2 A1 represents the dielectric constant of the blocking medium, A2 represents the area of ​​the DC negative voltage electrode facing the object being treated, U represents the DC negative voltage value, k represents the electrostatic constant, and d2 represents the distance between the DC negative voltage electrode and the object being treated.

[0014] In some embodiments, the method further includes: calculating the maximum ion implantation energy according to the following formula:

[0015] E 注入 =eU;

[0016] Among them, E 注入 represents the maximum ion injection energy, e represents the charge carried by the ion, and U represents the DC negative voltage value.

[0017] In some embodiments, the method further includes determining the maximum ion implantation depth based on the maximum ion implantation energy and the properties of the material being treated.

[0018] In some embodiments, the system is in a steady state with no current when the capacitance value is acquired.

[0019] In some embodiments, the capacitance value is obtained by theoretical calculation or by experimental measurement.

[0020] In some embodiments, the DC negative voltage electrode is a planar electrode structure, or a specific shape designed in conjunction with the shape of the object being processed.

[0021] In some embodiments, the material being treated is a membrane material made of polymeric materials and / or nanomaterials.

[0022] In some embodiments, the negative DC voltage is applied until the electric field is balanced before the ion implantation dose is measured.

[0023] In some embodiments, the plasma injection is a non-immersion ion implantation method.

[0024] The beneficial effects of this invention compared to the prior art include:

[0025] This invention calculates the amount of charge implanted into the ion-implanted material by acquiring the DC negative voltage value of the DC negative voltage electrode and the capacitance value between the DC negative voltage electrode and the charge layer on the surface of the ion-implanted material. This allows for precise determination of the ion implantation dose based on the amount of charge implanted. Unlike traditional methods, this invention measures the dose using system steady-state parameters before and after ion implantation. It eliminates the need for complex real-time online diagnostics of various ion implantation parameters and the need to separately measure changes in the electrical steady-state of the ion-implanted material before and after implantation. Only the electrical parameters before ion implantation and the structural parameters of the ion implanter itself are required to accurately determine the ion implantation dose. Furthermore, the maximum ion implantation energy and maximum implantation depth can be further measured. Since it eliminates the need for complex real-time online diagnostics of various transient parameters during ion implantation, this invention solves the problems of high technical difficulty and cost associated with traditional ion implantation measurement methods that require real-time high-precision detection of the implantation current. This significantly reduces the application cost of ion implantation technology and facilitates further industrial applications of PNII. This method can be widely used in the field of material surface modification, with a focus on the surface modification of membrane materials composed of polymers and nanomaterials.

[0026] Other beneficial effects of the embodiments of the present invention will be further described below. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a non-immersion ion implantation device for plasma in an embodiment of the present invention;

[0028] Figure 2This is a schematic diagram of plasma injection calculation in an embodiment of the present invention;

[0029] The attached figures are labeled as follows:

[0030] 1- AC high voltage electrode, 2- porous ground electrode, 3- DC negative voltage electrode, 4- the object being processed, 5- AC resistance medium, 6- DC resistance medium, 7- high frequency AC voltage, 8- DC negative voltage. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and preferred embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0032] It should be noted that the directional terms such as left, right, up, down, top, and bottom used in this embodiment are only relative concepts or are based on the normal use of the product, and should not be considered as restrictive.

[0033] Traditional ion implantation measurement methods require precise calculations of ion current density, implantation time, ion beam energy, angular distribution, and implantation area, which are technically demanding and costly.

[0034] This invention proposes a method for measuring ion implantation dose and maximum implantation depth by determining the DC negative voltage value of the DC negative voltage electrode based on electrical parameters before ion implantation, and by determining the capacitance between the DC negative voltage electrode and the treated object based on the structural parameters of the ion implanter itself. In other words, this invention can accurately obtain the ion implantation dose using only the steady-state parameters of the system before and after ion implantation. This method eliminates the need for real-time online calculation and diagnosis of various complex transient parameters during ion implantation. By calculating the implantation dose through offline measurement, it significantly simplifies the calculation cost of ion implantation, greatly reducing the application cost of ion implantation technology and facilitating the further industrial application of PNII.

[0035] The ion implantation dose measurement method proposed in this embodiment of the invention references the ion implantation device of patent application number CN202210887666.8, such as... Figure 1 As shown, the structure of the device is described as follows:

[0036] The ion implantation device includes an AC high-voltage electrode 1, a DC negative voltage electrode 3, and a porous ground electrode 2 located between the AC high-voltage electrode 1 and the DC negative voltage electrode 3. The area between the AC high-voltage electrode 1 and the porous ground electrode 2 is a plasma generation region, and the area between the porous ground electrode 2 and the DC negative voltage electrode 3 is an ion implantation region. A DC blocking medium 6 is disposed on the side of the DC negative voltage electrode 3 facing the porous ground electrode 2, and the object to be treated 4 is placed on the DC blocking medium 6. An AC blocking medium 5 is disposed on the side of the AC high-voltage electrode 1 facing the porous ground electrode 2. In this embodiment of the invention, the object to be treated 4 is a membrane material.

[0037] The principle and steps of ion implantation are as follows:

[0038] The material of the alternating current blocking dielectric 5 is plexiglass. A porous ground electrode 2 with an insulating dielectric barrier is designed between the AC high-voltage electrode 1 and the DC negative voltage electrode 3. The electrode region is divided into a plasma generation region and an ion implantation function adjustment region. The AC high-voltage electrode 1 is connected to a high-frequency AC voltage, the porous ground electrode 2 is grounded, and the DC negative voltage electrode 3 is connected to a DC negative voltage. In this embodiment of the invention, the porous ground electrode 2 is a mesh electrode.

[0039] The electrode structure is placed in a sealed discharge chamber, a specific working gas is introduced, and the pressure is evacuated to a low level. Plasma is generated between the AC high-voltage electrode 1 and the porous ground electrode 2. Charged particles in the plasma diffuse to the area between the porous ground electrode 2 and the DC negative voltage electrode 3 under the principle of bipolar diffusion. A DC negative high voltage is applied between the porous ground electrode 2 and the DC negative voltage electrode 3. Positive ions entering the area between the porous ground electrode 2 and the DC negative voltage electrode 3 are accelerated towards the DC negative voltage electrode 3 under the influence of a strong electric field, while negative ions / electrons are bounced back to the plasma generation area under the influence of the electric field, thus completing particle screening. The object to be treated 4 is placed on the surface of the DC negative voltage electrode 3. High-energy positive ions can obtain sufficiently high energy to achieve ion implantation into the object to be treated 4. By controlling the magnitude of the negative high voltage and the discharge time, the ion implantation depth and density can be customized to achieve specific modification effects.

[0040] The steps of the ion implantation dose measurement method proposed in this embodiment of the invention are as follows:

[0041] like Figure 2 As shown, the DC negative voltage value applied to the DC negative voltage electrode 3 and the capacitance value between the DC negative voltage electrode 3 and the charge layer on the upper surface of the workpiece 4 after ion implantation are obtained; then the amount of charge implanted into the workpiece 4 is calculated based on the DC negative voltage value and the capacitance value; finally, the ion implantation dose is determined based on the amount of charge implanted into the workpiece 4.

[0042] The steady-state parameters include the DC negative voltage electrode voltage value U and the capacitance value C2 between the DC negative voltage electrode 3 and the porous ground electrode 2.

[0043] The ion implantation process and ion implantation dose measurement method in this embodiment of the invention are described in detail below:

[0044] (1) Before ion implantation:

[0045] The DC negative voltage electrode 3 and the porous ground electrode 2 carry equal amounts of opposite charges, with equal charge surface densities δ1. The DC negative voltage electrode 3 is a DC negative high-voltage electrode, and its charge surface density δ1 depends on the capacitance C1 between the DC negative voltage electrode 3 and the porous ground electrode 2. The capacitance C1 is determined by the dielectric constant ε of the blocking medium. r1 The distance d1 between the DC negative voltage electrode 3 and the porous ground electrode 2 determines that the system is in a steady state with no current when the capacitance value C1 is obtained.

[0046] (2) During ion implantation:

[0047] A current is generated in the circuit, increasing the surface charge density of both the DC negative voltage electrode 3 and the porous ground electrode 2. During ion implantation, a DC negative voltage is used as the ion acceleration source. Ions move from the porous ground electrode 2 to the surface of the workpiece 4 under the electric field pointing from the DC negative voltage electrode 3. Since the ions are positively charged, a layer of positive charge accumulates on the surface of the workpiece 4. This layer of positive charge acts as a positive electrode, weakening the electric field between the porous ground electrode 2 and the workpiece 4. However, as long as the applied electric field pointing from the porous ground electrode 2 to the workpiece 4 exists, positive ions will continue to move towards the workpiece 4, increasing the positive charge accumulated on the surface of the workpiece 4. Ion implantation is complete when the electric field between the workpiece 4 and the porous ground electrode 2 becomes zero and the positive ions no longer move towards the DC negative voltage electrode 3. During ion implantation, because the ions move very quickly under the electric field (below micro-nanoseconds), it can be assumed that electric field equilibrium is reached within a few seconds.

[0048] (3) After ion implantation is completed:

[0049] The surface charge density of the DC negative voltage electrode 3 = the surface charge density of the porous electrode 2 = the surface charge density of the ions in the treated material 4 = δ2; where δ2 depends on the capacitance C2 between the DC negative voltage electrode 3 and the treated material 4, and the capacitance C2 is determined by the dielectric constant ε of the blocking medium. r2 The distance d2 between the DC negative voltage electrode 3 and the object being processed 4 is determined by the fact that the system is in a steady state with no current when the capacitance value C2 is obtained.

[0050] In the ion implantation dose measurement method, the capacitance value can be calculated based on structural parameters (the area of ​​the DC negative voltage electrode facing the object being treated, the distance between the DC negative voltage electrode and the object being treated, etc.) or obtained through experimental measurement; the DC negative voltage electrode is a planar electrode structure, or a specific shape designed in conjunction with the shape of the object being treated. The object being treated is a membrane material made of polymer materials and / or nanomaterials; a DC negative voltage is applied until the electric field is balanced before the ion implantation dose is measured; the plasma implantation measured by this method is a non-immersion ion implantation method.

[0051] After ion implantation, the amount of charge injected into the treated object is calculated based on the DC negative voltage and capacitance values. The specific implantation dose calculation formula is as follows:

[0052]

[0053] Among them, Q 注入 ε represents the amount of charge injected into the object being treated. r2 A1 represents the dielectric constant of the blocking medium, A2 represents the area of ​​the DC negative voltage electrode facing the object being treated, U represents the DC negative voltage value, k represents the electrostatic constant, and d2 represents the distance between the DC negative voltage electrode and the object being treated.

[0054] The maximum ion implantation energy is calculated using the formula for maximum implantation energy, which is expressed as follows:

[0055] E 注入 =eU;

[0056] Where E 注入 The maximum ion injection energy is defined as the energy that the ion can obtain, where e represents the charge carried by the ion and U represents the DC negative voltage value. The maximum ion injection energy means that the energy that the ion can obtain is less than or equal to this energy.

[0057] In this embodiment of the invention, the maximum ion implantation energy is obtained with reference to monovalent ions, where e is the charge of an electron. When the ion is divalent or trivalent, its charge is two and three times that of an electron, respectively.

[0058] The maximum ion implantation depth is determined based on the maximum ion implantation energy and the properties of the material being treated.

[0059] In different embodiments, the electrodes in the ion implantation device are not limited to flat electrode structures. Ion implantation electrodes of specific shapes can be designed in combination with the sample shape (such as spherical, prismatic, elliptical, etc.) or flexible electrodes can be used directly. Under the premise of uniform ion implantation of irregular samples, the ion implantation dose measurement method proposed in the embodiments of the present invention is applicable.

[0060] Compared to traditional methods, this invention measures the system steady-state parameters before and after ion implantation. It eliminates the need for complex real-time online diagnostics of various ion implantation parameters and the need to separately measure changes in the electrical steady-state of the treated material before and after implantation. Only the electrical parameters before ion implantation and the structural parameters of the ion implanter itself are required to accurately determine the ion implantation dose. Furthermore, the maximum ion implantation energy and maximum implantation depth can be measured. Because it eliminates the need for complex real-time online diagnostics of various transient parameters during ion implantation, this invention solves the problems of high technical difficulty and cost associated with traditional ion implantation measurement methods that require real-time, high-precision detection of the implantation current. This significantly reduces the application cost of ion implantation technology and facilitates the further industrial application of PNII.

[0061] The ion implantation dose measurement method proposed in this invention can be applied in all technical fields that require modification of material surfaces, with a focus on membrane materials composed of polymer materials and nanomaterials.

[0062] The above description provides a further detailed explanation of the present invention in conjunction with specific / preferred embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the concept of the present invention, and all such substitutions or modifications should be considered within the scope of protection of the present invention. In the description of this specification, the reference to terms such as "an embodiment," "some embodiments," "preferred embodiment," "example," "specific example," or "some examples," etc., indicates that the specific features, structures, materials, or characteristics described in connection with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications can be made herein without departing from the scope of protection of the patent application.

Claims

1. An ion implantation dose measurement method for measuring the ion implantation dose after ion implantation of a workpiece by an ion implantation device, wherein the ion implantation device includes an AC high-voltage electrode, a DC negative voltage electrode, and a porous ground electrode located between the AC high-voltage electrode and the DC negative voltage electrode, wherein a plasma generation region is located between the AC high-voltage electrode and the porous ground electrode, and an ion implantation region is located between the porous ground electrode and the DC negative voltage electrode, wherein a barrier medium is disposed on the side of the DC negative voltage electrode facing the porous ground electrode, and the workpiece is placed on the barrier medium; Its features are, The measurement method includes the following steps: The DC negative voltage value applied to the DC negative voltage electrode and the capacitance value between the DC negative voltage electrode and the charge layer on the upper surface of the treated material after ion implantation are obtained. The amount of charge injected into the object being treated is calculated based on the DC negative voltage value and the capacitance value. The ion implantation dose is determined based on the amount of charge injected into the object being treated; In this method, a DC negative voltage is applied until the electric field is balanced before the ion implantation dose is measured. When the capacitance value is obtained, the system is in a steady state with no current. The measurement method measures the ion implantation dose by using the steady-state parameters of the system before and after ion implantation, without needing to measure various transient parameters during the ion implantation process.

2. The ion implantation dose measurement method as described in claim 1, characterized in that, The calculation of the amount of charge injected into the object being treated based on the DC negative voltage value and the capacitance value is performed according to the following formula: ； in, This indicates the amount of charge injected into the object being treated. This represents the dielectric constant of the blocking medium. U represents the area directly opposite the DC negative voltage electrode and the object being treated, where U represents the DC negative voltage value. Represents the electrostatic constant. This indicates the distance between the DC negative voltage electrode and the object being processed.

3. The ion implantation dose measurement method as described in claim 1 or 2, characterized in that, Also includes: The maximum ion implantation energy is calculated using the following formula: ； in, represents the maximum ion injection energy, e represents the charge carried by the ion, and U represents the DC negative voltage value.

4. The ion implantation dose measurement method as described in claim 1 or 2, characterized in that, Also includes: The maximum ion implantation depth is determined based on the maximum ion implantation energy and the properties of the material being treated.

5. The ion implantation dose measurement method as described in claim 1 or 2, characterized in that, The capacitance value is obtained by theoretical calculation or by experimental measurement.

6. The ion implantation dose measurement method as described in claim 1 or 2, characterized in that, The DC negative voltage electrode is a flat plate electrode structure, or a specific shape designed in conjunction with the shape of the object being processed.

7. The ion implantation dose measurement method as described in claim 1 or 2, characterized in that, The material being processed is a membrane material made of polymer materials.

8. The ion implantation dose measurement method as described in claim 1 or 2, characterized in that, The material being processed is a membrane material made of nanomaterials.

9. The ion implantation dose measurement method according to any one of claims 1 to 2, characterized in that, The plasma injection is a non-immersion ion implantation method.

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