Cleaning method of ion implanter

Abstract

The invention relates to the technical field of semiconductor processing, particularly provides a cleaning method of an ion implanter, and aims to solve the problem that an existing ion implanter needs to be shut down for cleaning. In order to achieve the purpose, the cleaning method of the ion implanter comprises the steps that a target material is placed in an implantation cavity of the ion implanter; and a first ion beam for bombarding the target material is injected into the injection cavity of the ion implanter, so that a charge accumulation layer is formed on the surface of the target material to adsorb suspended pollutant particles, and the purpose of cleaning the ion implanter is achieved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of semiconductor processing, and specifically provides a cleaning method for an ion implanter. Background Art

[0002] In the semiconductor manufacturing process, ion implantation has become an indispensable and important process due to its high purity and precise control. The ion implantation process uses an ion beam to bombard the target material in a high vacuum system to implant ions into the target material. The ions are blocked by the target atoms and stay there, thus achieving the purpose of doping.

[0003] The equipment used in the ion implantation process is an ion implanter. During the ion implantation process using the ion implanter, the ion beam first passes through the beam path (i.e., the channel through which the ion beam passes), and then enters the implantation chamber (i.e., the chamber processed by the ion implanter) to continuously bombard the target material and the inner wall of the implantation chamber, causing the particles on the target material and the inner wall of the implantation chamber to fall off and form suspended pollutant particles. In addition, the inner wall of the beam path is wrapped with graphite parts for protection. The ion beam will bombard the graphite parts during the beam path, causing some particles of the graphite parts to fall off and form suspended pollutant particles. As the number of pollutant particles injected into the chamber increases, it will affect the processing results of the ion implanter. Therefore, it is necessary to clean the pollutant particles on the inner wall of the chamber and suspended inside to ensure the processing effect of the product.

[0004] However, the existing cleaning method of the ion implanter requires opening the injection chamber of the ion implanter and cleaning the inner wall of the injection chamber of the ion implanter. However, in the process of opening the injection chamber for cleaning, the ion implanter needs to be shut down, and after the cleaning is completed, the injection chamber of the ion implanter needs to be evacuated again to maintain the vacuum state, resulting in a long time for the ion implanter from the beginning of cleaning to the resumption of production, affecting production efficiency. In addition, the whole process is time-consuming and labor-intensive, and if a certain link is not handled properly during the process of opening the injection chamber, other faults will occur, thereby further shortening the available time of the ion implanter. Therefore, there is an urgent need for a cleaning method for an ion implanter to solve the problem that the existing ion implanter needs to be shut down for cleaning. Summary of the invention

[0005] The present disclosure aims to solve the above technical problem, that is, to solve the problem that the existing ion implanter needs to be shut down for cleaning. In a first aspect, the present disclosure provides a cleaning method for an ion implanter, comprising: placing a target material in an implantation chamber of the ion implanter; injecting a first ion beam bombarding the target material into the implantation chamber of the ion implanter to form a charge accumulation layer on the surface of the target material to adsorb suspended contaminant particles located in the implantation chamber.

[0006] In some embodiments, the cleaning method of the ion implanter further includes injecting a second ion beam bombarding the target material into the implantation chamber of the ion implanter before injecting a first ion beam bombarding the target material into the implantation chamber of the ion implanter; wherein the injection energy of the second ion beam is greater than the injection energy of the first ion beam, and the ion beam current of the second ion beam is greater than the ion beam current of the first ion beam.

[0007] In some embodiments, the first ion beam is configured to form a charge accumulation layer on the surface of the target material to adsorb suspended contaminant particles located in the injection cavity, and the second ion beam is configured to bombard the inner wall of the injection cavity after being scattered by the target material, so that the contaminant particles attached to the inner wall of the injection cavity are partially fallen off to form suspended contaminant particles.

[0008] In some embodiments, an implantation dose of the second ion beam is less than or equal to an implantation dose of the first ion beam.

[0009] In some embodiments, the implantation dose of the first ion beam and / or the second ion beam is 1*10 12 ion / cm 2 Up to 1*10 16 ion / cm 2 ; and / or, the implantation energy of the first ion beam and / or the second ion beam is less than or equal to 100KeV; and / or, the implantation energy of the first ion beam and / or the second ion beam is greater than or equal to 20KeV.

[0010] In some embodiments, the target material includes a substrate and an insulating dielectric layer covering the substrate.

[0011] In some embodiments, a side of the insulating dielectric layer away from the substrate has grooves arranged in an array.

[0012] In some embodiments, the second ion beam is implanted in multiple directions with an angle; and / or the implantation direction of the first ion beam is perpendicular to the bottom surface of the groove.

[0013] In some embodiments, the cleaning method further includes: detecting a cleaning result of the ion implanter.

[0014] In some embodiments, detecting the cleaning effect of the ion implanter includes: measuring the number A1 of first particles and the number A2 of second particles on the surface of a fake film before ion beam injection, wherein the diameter of the first particles is less than or equal to a preset diameter, and the diameter of the second particles is greater than the preset diameter; placing the fake film on the table of the ion implanter, and injecting a preset ion beam under preset conditions; taking out the fake film and measuring the number B1 of first particles and the number B2 of second particles on the surface of the fake film after ion beam injection; determining whether the cleaning result meets the standard based on the number A1 of first particles and the number A2 of second particles on the surface of the fake film before ion beam injection and the number B1 of first particles and the number B2 of second particles on the surface of the fake film after ion beam injection.

[0015] In some embodiments, the cleaning result is determined based on the number A1 of the first particles and the number A2 of the second particles on the surface of the fake film before ion beam injection and the number B1 of the second particles and the number B2 of the first particles on the surface of the fake film after ion beam injection, including: if C1 is less than a first preset value and C2 is less than a second preset value, the cleaning result meets the standard, wherein C1=(B1+B2)-(A1+A2), C2=(B2-A2); and / or, if C1 is greater than or equal to the first preset value or C2 is greater than or equal to the second preset value, the cleaning result does not meet the standard, the ion implanter is cleaned again, and the first ion beam is re-injected into the implantation chamber of the ion implanter.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] In the cleaning method of the ion implanter provided by the present disclosure, a first ion beam is injected into a target material, so that a charge accumulation layer can be formed on the surface of the target material to adsorb suspended pollutant particles, thereby achieving the purpose of cleaning the ion implanter.

[0018] Furthermore, before injecting the first ion beam, a second ion beam with high injection energy and large ion beam current is injected to bombard the inner wall of the injection chamber, so that the pollutant particles attached to the inner wall of the injection chamber are bombarded off to form suspended pollutant particles, and at the same time, some of the suspended pollutant particles can also be adsorbed by the charge accumulation layer formed on the surface of the target material; the first ion beam with low injection energy and small ion beam current is used to form a charge accumulation layer on the surface of the target material that can adsorb the suspended pollutant particles, and fewer or no suspended pollutant particles are formed during the injection process, so as to maximize the cleaning efficiency of the suspended pollutant particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The preferred embodiments of the present disclosure are described below in conjunction with the accompanying drawings, in which:

[0020] Figure 1is a flow chart of a cleaning method for an ion implanter provided by the present disclosure;

[0021] Figure 2 is a cross-sectional view of a target material provided by the present disclosure;

[0022] Figure 3 is a top view of the target material provided by the present disclosure;

[0023] Figure 4 is a schematic diagram of the ion beam implantation direction provided by the present disclosure;

[0024] Figure 5 It is a schematic diagram of the ion beam implantation direction provided by the present invention.

[0025] Description of reference numerals:

[0026] 1. Substrate; 2. Insulating dielectric layer; 21. Groove. DETAILED DESCRIPTION

[0027] The preferred embodiments of the present disclosure are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present disclosure and are not intended to limit the scope of protection of the present disclosure. It should also be noted that in the description of the present disclosure, "first", "second" and similar expressions are only used for distinction and do not represent priority or quantity.

[0028] In order to solve the problem of a large amount of residual pollutant particles in the existing ion implanter, the present disclosure provides a cleaning method for the ion implanter, such as Figure 1 As shown, the method includes: placing a target material in an implantation chamber of an ion implanter; injecting a first ion beam into the implantation chamber of the ion implanter to bombard the target material, so as to form a charge accumulation layer on the surface of the target material to adsorb suspended pollutant particles in the implantation chamber.

[0029] The cleaning methods of the ion implanter of some embodiments of the present disclosure are described below through several specific examples.

[0030] Embodiment 1

[0031] The cleaning method of the ion implanter of the embodiment of the present disclosure includes:

[0032] S100: Prepare target material.

[0033] The target material includes a substrate 1. Under the condition that the processing requirements of the ion implantation machine are met, the substrate 1 of the target material can be made of any material, such as silicon, silicon carbide, gallium arsenide, etc.

[0034] In some examples, such as Figure 2As shown, the surface of the substrate 1 of the target material is covered with an insulating dielectric layer 2, and the material of the insulating dielectric layer 2 can be an inorganic layer such as silicon nitride and silicon dioxide. For example, the material of the substrate 1 is silicon, and the material of the insulating dielectric layer 2 is silicon oxide. After the ion implanter is cleaned, since the contaminant particles are adsorbed on the insulating dielectric layer 2 of the target material, an uncontaminated substrate 1 can be obtained by removing the insulating dielectric layer 2, and the insulating dielectric layer 2 can be re-formed on the surface of the substrate 1 and can be used again, thereby saving the cost of using the target material.

[0035] As a preferred embodiment, the material of the substrate is silicon, and the material of the insulating dielectric layer 2 is silicon dioxide. Since silicon-based substrates are widely used in semiconductor manufacturing plants and are relatively cheap compared to other material substrates; in addition, the silicon dioxide grown on the silicon-based substrate is highly stable, and it is also relatively easy to remove silicon dioxide on the silicon-based substrate, so silicon-based substrates are preferably used. In addition, the SiO2 layer on the surface of the silicon-based substrate with silicon dioxide can be removed after one use, so that it can return to the initial silicon-based substrate state, so the silicon-based substrate can be reused.

[0036] The thickness of the insulating dielectric layer 2 can be selected accordingly according to the capability of the equipment for growing the insulating dielectric layer 2. Of course, the thickness of the insulating dielectric layer 2 should not be too thick, otherwise it may cause deformation of the target material; at the same time, the thickness of the insulating dielectric layer 2 should not be too thin, otherwise the ions subsequently injected into the injection chamber of the ion implanter will penetrate the insulating dielectric layer 2, thereby reducing the adsorption efficiency of the insulating dielectric layer 2. In the example disclosed in the present invention, the thickness of the insulating dielectric layer 2 is between 3000 angstroms and 10000 angstroms.

[0037] The surface of the insulating dielectric layer 2 can be set to a flat surface, or can be set to a curved surface to increase the surface area of ​​the insulating dielectric layer 2, thereby increasing the area where the target material can adsorb pollutant particles, thereby increasing the adsorption capacity of the target material. Figure 2 and Figure 3 As shown, in the example of the present disclosure, the insulating dielectric layer 2 is patterned so that the surface of the insulating dielectric layer 2 on the side away from the substrate 1 has grooves 21 arranged in an array. The more and denser the grooves 21 are, the larger the surface area of ​​the insulating dielectric layer 2 is, and the stronger the adsorption capacity of the target material is.

[0038] Of course, in other possible examples, the substrate 1 may also be directly used as a target material.

[0039] S200 , injecting a first ion beam into an implantation chamber of an ion implanter, and bombarding a target material with the first ion beam.

[0040] Wherein, the ion beam carries a positive charge. After the first ion beam bombards the target material, the surface of the target material can be positively charged to form a charge accumulation layer, specifically, the charge accumulation layer is formed on the surface of the insulating dielectric layer 2. The inner side wall of the injection cavity is grounded, and the zero potential is always maintained to reduce the possibility of the pollutant particles suspended in the injection cavity being adsorbed to the inner side wall of the injection cavity. Since the target surface has a positively charged charge accumulation layer, and the charged object has the ability to attract light and small objects, therefore, under the action of the electrostatic force of the charge accumulation layer, the pollutant particles suspended in the injection cavity will be adsorbed on the surface of the insulating dielectric layer 2 of the target material, achieving the effect of cleaning the pollutant particles in the injection cavity. Based on this, it can be understood that the process of forming a charge accumulation layer on the surface of the insulating dielectric layer 2 is the process of cleaning the pollutant particles suspended in the injection cavity. It is not difficult to see from this that the cleaning method of the ion implanter disclosed in the present application does not need to open the injection cavity of the ion implanter, and the pollutant particles suspended in the injection cavity can be cleaned, so at least the number of times the ion implanter is shut down for cleaning in the production process can be reduced, thereby improving production efficiency. In addition, other malfunctions that may be caused by opening the injection cavity are also avoided.

[0041] After the charged first ion beam enters the injection cavity, the charge in the first ion beam will be transferred to the surface of the target material to form a charge accumulation layer. Generally speaking, in order to make the ion beam (including the first ion beam and the second ion beam mentioned later) completely cover the surface of the target material (specifically, cover the surface of the insulating dielectric layer 2), the bombardment range of the ion beam will be larger than the size of the target material. Therefore, a part of the ion beam will bombard the partial area outside the target material. The ion beam bombarding the target material and the area outside the target material will produce scattering, and these scattered ions will further bombard other components inside the injection cavity. The pollutant particles attached to these components will be detached and suspended in the injection cavity after being bombarded by the ions, and then attracted by the charge accumulation layer and adsorbed on the target material.

[0042] Therefore, after the first ion beam enters the injection chamber, part of the charge will be transferred to the surface of the target material to form a charge accumulation layer, part of the charge will be introduced into the ground through the inner wall of the injection chamber, and a very small part will be filled in the injection chamber with the ions suspended in the injection chamber.

[0043] The injection gas forming the first ion beam may be any gas that can be used for ion injection, such as borane (BF3), phosphine (PH3), arsine (AsH3), argon (Ar), xenon (Xe) and the like.

[0044] In addition, when the surface of the insulating dielectric layer 2 has grooves 21 arranged in an array, the first ion beam can be implanted in multiple directions with an angle. The use of the angled multiple directions to implant the first ion beam can make each side of the groove 21 better contact with the ion beam to form a charge accumulation layer.

[0045] In the examples of the present disclosure, Figure 4 As shown, the groove 21 is a rectangular groove, and the injection orientation of the first ion beam is four orientations to ensure that the first ion beam can fully contact the four sides of the groove 21. One quarter of the injection dose is injected in each orientation, and after the injection of one orientation is completed, another orientation is changed for injection. The angle between the injection direction of the first ion beam and the normal to the bottom surface of the groove 21 cannot be 0°, so as to prevent the side wall of the groove 21 from being unable to fully contact the ion beam. In addition, the angle between the injection direction of the first ion beam and the normal to the bottom surface of the groove 21 should not be too large, otherwise part of the ion beam will be blocked by the side wall of the groove 21, resulting in the first ion beam being unable to fully contact the bottom surface of the groove 21 and the part of the side of the groove 21 close to the bottom surface. Specifically, the angle between the injection direction and the normal to the bottom surface of the groove 21 is one of 0° to 10°, and cannot be 0°.

[0046] In the example disclosed in the present invention, the implantation dose of the first ion beam is 1*10 12 i on / cm 2 Up to 1*10 16 i on / cm 2 , where ion represents a charged particle. The implantation dose of the first ion beam is the number of ions implanted per unit area of ​​the target surface. The implantation dose of the first ion beam cannot be too small, otherwise the number of implanted ions will be insufficient, affecting the removal effect of pollutant particles; the implantation dose of the first ion beam cannot be too large, otherwise the time for ion implantation will be extended. If a large number of pollutant particles have been adsorbed on the target surface and ion implantation is still performed, the pollutant particles adsorbed on the target surface may be detached after bombardment and be in a suspended state, thereby reducing the cleaning efficiency.

[0047] The injection energy of the first ion beam cannot be too high, otherwise the first ion beam is easy to damage and penetrate the insulating dielectric layer 2, so that the charge amount in the charge accumulation layer formed on the surface of the insulating dielectric layer 2 is reduced. In the example disclosed in the present invention, the injection energy of the first ion beam is less than or equal to 100 KeV and the injection energy is greater than or equal to 20 KeV. Of course, the specific injection energy of the first ion beam can be adjusted according to the thickness of the insulating dielectric layer 2 and the machine capacity of the ion implanter itself.

[0048] S300, detecting the cleaning result of the ion implanter to determine whether the cleaning result of the ion implanter meets the standard. It specifically includes the following steps:

[0049] S301, prepare a dummy wafer. The size of the dummy wafer is selected according to the size of the wafer processed by different machines.

[0050] S302, measure the number A1 of first particles and the number A2 of second particles on the surface of the fake film before the preset ion beam is injected. The diameter of the first particle is less than or equal to the preset diameter, and the diameter of the second particle is greater than the preset diameter. The preset diameter is used to distinguish small particles (first particles) from large particles (second particles). The minimum particle size that can be measured by the particle detector is set according to the process node of the processed product in the ion implanter. In a specific example of the present disclosure, the minimum particle size that can be measured by the particle detector is 0.2μm, and the preset diameter is 1μm.

[0051] Of course, the number A1 of the first particles and the number A2 of the second particles on the surface of the dummy film before the preset ion beam is injected need to meet certain requirements, otherwise the dummy film is a defective product and cannot be used to detect the cleaning effect of the ion implanter. Specifically, A1+A2 is less than a preset value, and the preset value is set according to the requirements of the manufacturer, for example, 100.

[0052] S303, placing the dummy film on the machine table of the ion implanter, and implanting the preset ion beam under preset conditions.

[0053] In the example of the present disclosure, the parameters of the preset ion beam are as follows: the injection gas is BF3, the injection ions are B+, the injection energy is 30 KeV, and the injection dose is 5*10 14 i on / cm 2 , the injection ion beam current is 3mA; the preset conditions are as follows: turn on the electron bath, the electron bath gas is argon, the argon flow rate is 0.5ccm, the arc starting current is 1.5A, the arc starting voltage is 23V, and the extraction voltage is 2V. Of course, the above preset conditions and the preset ion beam for injection are only examples, and can be selected according to the requirements of the ion implanter and the manufacturer for the product, as long as it is within the maximum processing capacity that the ion implanter can achieve and meets the process requirements of the product that the manufacturer needs to process.

[0054] S304 , taking out the dummy film, and measuring the number B1 of the first particles and the number B2 of the second particles on the surface of the dummy film after the preset ion beam is injected.

[0055] S305 , determining whether the cleaning result meets the standard based on the number A1 and the number A2 of the first particles on the surface of the dummy film before the preset ion beam is injected and the number B1 and the number B2 of the first particles on the surface of the dummy film after the preset ion beam is injected.

[0056] Specifically, C1 = (B1 + B2) - (A1 + A2), C2 = (B2 - A2), the smaller the values ​​of C1 and C2, the fewer the number of pollutant particles injected into the cavity. If C1 is less than the first preset value and C2 is less than the second preset value, the cleaning result meets the standard; if C1 is greater than or equal to the first preset value or C2 is greater than or equal to the second preset value, the cleaning result does not meet the standard and steps S100 to S300 need to be re-executed. The first preset value and the second preset value will be set according to the requirements of the manufacturer. In the example disclosed in the present invention, the first preset value is 100 and the second preset value is 10.

[0057] In some possible examples, the cleaning method of the ion implanter further includes:

[0058] S000: Detecting the number of pollutant particles existing on the implantation chamber of the ion implanter. Step S000 is performed before step S100.

[0059] Wherein step S000 is the same as step S301 to step S304, and the measurement results obtained are C1′ and C2′, and the calculation formula of C1′ and C2′ is the same as the calculation formula of C1 and C2. The values ​​of C1′ and C2′ can be used to roughly judge the number of contaminant particles existing in the injection cavity of the ion implanter, so as to judge whether the injection cavity of the ion implanter needs to be cleaned. If cleaning is required, the injection parameters of the first ion beam (such as injection dose, etc.) can be adjusted according to the measurement results.

[0060] In addition, (C1′-C1) can represent the number of pollutant particles adsorbed on the surface of the fake film after step S100 to step S202, and (C2′-C2) can represent the number of second pollutant particles adsorbed on the surface of the fake film after step S100 to step S202. By comparing the values ​​of (C1′-C1) and (C2′-C2), the cleaning effect of step S100 to step S202 can be obtained, wherein the larger the value, the better the cleaning effect. Of course, the cleaning effect is not the same as the cleaning result. The final judgment of whether the cleaning result of the ion implanter meets the standard is based on whether the values ​​of C1 and C2 meet the requirements.

[0061] In summary, the embodiments of the present disclosure have at least the following technical effects:

[0062] (1) A first ion beam is injected into an injection chamber of an ion implanter to bombard the target material. The first ion beam can form a charge accumulation layer on the surface of the target material. The charge accumulation layer can adsorb pollutant particles suspended in the injection chamber, thereby cleaning the pollutant particles in the injection chamber.

[0063] (2) During the cleaning process of the ion implanter, it is not necessary to open the implantation chamber of the ion implanter and it is not necessary to change the vacuum state of the ion implanter, which effectively saves the cleaning time and also avoids other faults caused by opening the implantation chamber.

[0064] (3) During the cleaning process of the ion implanter, the ion implanter is always in a production-ready state. After the cleaning is completed, the production operation can be carried out directly without any other additional operations, which greatly improves the equipment utilization rate and also improves the production efficiency.

[0065] Embodiment 2

[0066] Since the charge accumulation layer can only adsorb pollutant particles suspended in the injection cavity, it is difficult to adsorb pollutant particles with strong adhesion on the inner wall of the injection cavity. In detail, in the first embodiment of the present disclosure, in order to achieve a cleaning effect, the first ion beam injected into the injection cavity, most of the ion beam can form a charge accumulation layer on the surface of the target material to adsorb the pollutant particles injected into the cavity, and only a relatively small part of the ion beam can bombard the inner wall of the injection cavity after scattering, so that a small amount of pollutant particles attached to the inner wall of the injection cavity are detached to form pollutant particles suspended in the injection cavity.

[0067] If the injection energy of the first ion beam is increased, a larger number of suspended pollutant particles will be generated by bombarding the inner wall of the injection chamber; but at the same time, the first ion beam with a higher injection energy is also continuously bombarding the target material, causing the pollutant particles adsorbed to the surface of the target material to detach again, thereby affecting the final cleaning effect. Therefore, when the first ion beam is used to clean the injection chamber, the effect on the pollutant particles attached to the inner wall of the injection chamber is limited. Of course, it should be specially pointed out that the above analysis does not mean that the cleaning effect of the cleaning method of the ion implanter provided in Example 1 is not ideal, but the embodiment of the present disclosure is proposed based on the above analysis to achieve a better cleaning effect.

[0068] The steps of the cleaning method of the ion implanter provided in the embodiment of the present disclosure are substantially the same as those of the cleaning method of the ion implanter provided in the first embodiment, except for step S200.

[0069] Step S200 of the embodiment of the present disclosure further includes:

[0070] S202, before injecting the first ion beam into the injection cavity of the ion implanter, injecting the second ion beam into the injection cavity of the ion implanter, the second ion beam bombards the target material, wherein the injection energy of the second ion beam is greater than the injection energy of the first ion beam, and the ion beam current of the second ion beam is greater than the ion beam current of the first ion beam. In other words, the second ion beam is configured as follows: when the second ion beam bombards the target material, due to the high injection energy and high ion beam current of the second ion beam, the second ion beam bombarding the target material and the components outside the target material will be scattered, and the second ion beam bombards the inner wall of the injection cavity after being scattered by the target material, so that the pollutant particles attached to the inner wall of the injection cavity fall off, so as to form pollutant particles suspended in the injection cavity. In detail, the injection energy and ion beam current of the second ion beam are large, the number of ions bombarding the target material per unit time is large, and the ion energy is large, which can more fully bombard the pollutant particles attached to the inner wall of the injection cavity, so that they fall off and suspend in the injection cavity, so as to be adsorbed by the target material with a charge accumulation layer. Of course, some of the charges in the second ion beam will also be able to accumulate on the target surface to absorb the suspended pollutant particles. Therefore, it is not difficult to understand that after the second ion beam is injected and before the first ion beam is injected, compared with before the second ion beam is injected, the pollutant particles suspended in the injection cavity may increase due to the detachment of the pollutant particles on the inner wall of the injection cavity. When there are fewer pollutant particles on the inner wall of the injection cavity, in this case, since the charges accumulated by the second ion beam on the target surface will absorb the suspended pollutant particles, the suspended pollutant particles in the injection cavity may also decrease after the second ion beam is injected.

[0071] After the second ion beam is injected, the first ion beam is injected into the injection chamber of the ion implanter. Since the ion beam current of the first ion beam is less than that of the second ion beam, the number of ions bombarding the target material per unit time by the first ion beam is relatively small, and the number of ions scattered into the injection chamber after being reflected by the target material is also relatively small, which reduces the possibility of bombarding the pollutant particles located on the inner wall of the injection chamber; at the same time, since the injection energy of the first ion beam is less than the injection energy of the second ion beam, after the bombardment of the second ion beam, the pollutant particles with weak adhesion are basically bombarded from the inner wall of the injection chamber by the second ion beam to form suspended pollutant particles. The main purpose of injecting the first ion beam with lower energy is to continuously form a charge accumulation layer on the surface of the target material, while generating fewer or even no suspended pollutant particles, so as to utilize the charge accumulation layer to adsorb the suspended pollutant particles suspended in the injection chamber, so as to achieve the purpose of cleaning the injection chamber. Therefore, the contaminant particles adhering to the inner wall of the injection chamber are bombarded down by utilizing the second ion beam having higher injection energy and larger ion beam current, and the suspended contaminant particles are cleaned by utilizing the charge accumulation layer formed on the target surface by utilizing the first ion beam having lower injection energy and smaller ion beam current. In this way, the contaminant particles adhering to the inner wall of the injection chamber can be cleaned, which not only improves the cleaning effect, but also reduces the number of times the ion implanter is shut down for cleaning, or even eliminates the need to shut down the ion implanter for cleaning.

[0072] In an example of the present disclosure, the implantation energy of any one of the first ion beam and the second ion beam is greater than or equal to 20 KeV, and the implantation energy of any one of the first ion beam and the second ion beam is less than or equal to 100 KeV. Optionally, the first ion beam can be between 20 KeV and 60 KeV, and the implantation energy of the second ion beam can be between 40 KeV and 100 KeV. The ion beam currents of the first ion beam and the second ion beam can be in the range of 0.015 mA to 7 mA. Optionally, the ion beam current of the first ion beam can be in the range of 1 mA to 5 mA, and the ion beam current of the second ion beam can be in the range of 4.5 mA to 7 mA. If the injection energy of the first ion beam and the second ion beam is too low, the ion beam will expand, and the expanded ion beam will bombard the pollutant particles adsorbed on the side wall of the beam path (the channel before the ion beam enters the injection chamber) and bring them into the injection chamber, thereby increasing the number of suspended pollutant particles in the injection chamber; at the same time, the expanded ion beam bombarding the beam path will cause the ion beam transmission efficiency to be too low, resulting in a smaller ion beam current entering the injection chamber, thereby reducing the cleaning effect.

[0073] The injection gas forming the second ion beam can be any gas that can be used for ion injection, such as borane (BF3), phosphine (PH3), arsine (AsH3), argon (Ar), xenon (Xe) and other gases. The injection gas forming the second ion beam can be the same as or different from the injection gas forming the first ion beam. In addition, under the same injection energy, the larger the mass number of the ion, the greater the kinetic energy, and the more easily the pollutant particles with greater adhesion can be bombarded off. Among them, argon is cheaper and purer than other gases, so argon is given priority as the injection gas. For bombardment efficiency considerations, the second ion beam can also use arsine (AsH3) with a larger mass number as the injection gas.

[0074] In an embodiment of implanting a second ion beam, as Figure 4 As shown, the second ion beam is implanted in four directions, and one quarter of the implant dose is implanted in each direction. After one direction is implanted, another direction is implanted. The angle between the implantation direction of the second ion beam and the normal line of the bottom surface of the groove 21 is one of 0° to 10°, and cannot be 0°. Figure 5 As shown, the angle between the implantation direction of the first ion beam and the normal line of the bottom surface of the groove 21 may be 0°, so that the first ion beam can fully contact the bottom surface of the groove 21 .

[0075] In the example disclosed in the present invention, the implantation dose of the first ion beam and the second ion beam are both 1*10 12 ion / cm 2 Up to 1*10 16 ion / cm 2 , and the implantation dose of the first ion beam is greater than or equal to the implantation dose of the second ion beam. The implantation dose of the ion beam is proportional to the product of the ion beam current and the implantation time. Since the implantation dose of the first ion beam is greater than the implantation dose of the second ion beam and the ion beam current of the first ion beam is less than the ion beam current of the second ion beam, the implantation time of the first ion beam is greater than the implantation time of the second ion beam. By making the implantation time of the first ion beam greater than the implantation time of the second ion beam, the target material has enough time to adsorb the pollutant particles suspended in the injection cavity to enhance the cleaning effect. In addition, during the injection of the first ion beam, by making the implantation dose of the first ion beam greater than the implantation dose of the second ion beam, a charge accumulation layer with a larger amount of charge can be generated on the surface of the target material to enhance the adsorption effect of the target material.

[0076] In addition, the cumulative implantation dose of the ion beam (including the first ion beam and the second ion beam) implanted on a single target cannot exceed 1*10 17 ion / cm 2 Generally speaking, when the cumulative injection dose exceeds 1*10 17 ion / cm 2When the number of pollutant particles adsorbed on the target surface is too large, the probability that the pollutant particles adsorbed on the target surface will be bombarded off again increases, thereby reducing the cleaning efficiency.

[0077] After the first ion beam is implanted, the target is taken out. For a target having an insulating dielectric layer on the surface, the insulating dielectric layer can be removed as needed and a new insulating dielectric layer can be re-formed for next use. In addition, the insulating dielectric layer may not be removed depending on the situation.

[0078] In addition, ion implanters are generally equipped with an electron bath device, which can provide electrons to neutralize the positive charge of the ion beam current. During the process of injecting the first ion beam and the second ion beam into the implantation chamber of the ion implanter, the electron bath device is turned off to prevent the electrons generated by the electron bath from neutralizing the positive charge on the charge accumulation layer and affecting the adsorption effect of the target material on the pollutant particles, thereby affecting the efficiency of cleaning the pollutant particles. For ion implanters that cannot turn off the electron bath device, the electron bath needs to be set to the lowest level to minimize the neutralization effect on the positive charge on the charge accumulation layer.

[0079] In addition, the present disclosure introduces several experimental examples to demonstrate the cleaning effect of the cleaning method for the ion implanter provided by the present disclosure.

[0080] Experimental Example 1

[0081] S000. Detect the number of pollutant particles existing in the implantation chamber of the ion implanter before cleaning.

[0082] Thus, the increase numbers C1′ and C2′ of the contaminant particles on the surface of the fake film before and after the detection are obtained, wherein C1′ is 172 and C2′ is 19. Then, the implantation chamber of the ion implanter is cleaned.

[0083] S100: Prepare target material.

[0084] The target substrate is made of silicon, and the substrate is covered with an insulating dielectric layer. The insulating dielectric layer is made of silicon nitride, has a thickness of 4000 angstroms, and has a flat top surface.

[0085] S200 , injecting a first ion beam into the injection chamber.

[0086] The parameters of the first ion beam are as follows: the injection gas is arsine, and the injection dose is 1*10 16 ion / cm 2 The implantation energy is 100 KeV, the ion beam current is 4 mA, and the electron bath device is turned off during the implantation of the first ion beam.

[0087] S300, detecting the number of pollutant particles existing in the implantation chamber of the ion implanter after cleaning.

[0088] Step S300 is the same as the above-mentioned steps S301 to S304, so as to obtain the increase numbers C1 and C2 of the pollutant particles on the surface of the fake film before and after the detection, where C1 is 77 and C2 is 7.

[0089] After calculation, (C1′-C1)=95, (C2′-C2)=12. It can be seen that Experimental Example 1 can reduce the number of pollutant particles in the implantation chamber of the ion implanter.

[0090] Experimental Example 2

[0091] S000. Detect the number of suspended pollutant particles existing in the injection chamber of the ion implanter before cleaning.

[0092] Thus, the increase numbers C1′ and C2′ of the contaminant particles on the surface of the fake film before and after the detection are obtained, wherein C1′ is 225 and C2′ is 9. Then, the implantation chamber of the ion implanter is cleaned.

[0093] S100: Prepare target material.

[0094] The target substrate is made of silicon, and the substrate is covered with an insulating dielectric layer. The insulating dielectric layer is made of silicon oxide, has a thickness of 8000 angstroms, and has a flat top surface.

[0095] S200 , injecting a first ion beam into the injection chamber.

[0096] The parameters of the first ion beam are as follows: the injection gas is argon, the injection dose is 5*10 15 ion / cm 2 The implantation energy is 50 KeV and the ion beam current is 4 mA. The electron bath device is turned off during the implantation of the first ion beam.

[0097] S300, detecting the number of pollutant particles existing in the implantation chamber of the ion implanter after cleaning.

[0098] Step S300 is the same as the above-mentioned steps S301 to S304, so as to obtain the increase numbers C1 and C2 of the pollutant particles on the surface of the fake film before and after the detection, where C1 is 85 and C2 is 5.

[0099] After calculation, (C1′-C1)=140, (C2′-C2)=4. It can be seen that Experimental Example 2 can reduce the number of pollutant particles in the implantation chamber of the ion implanter.

[0100] Experimental Example 3

[0101] S000. Detect the number of pollutant particles existing in the implantation chamber of the ion implanter before cleaning.

[0102] Thus, the increase numbers C1′ and C2′ of the contaminant particles on the surface of the fake film before and after the detection are obtained, wherein C1′ is 166 and C2′ is 24. Then, the implantation chamber of the ion implanter is cleaned.

[0103] S100: Prepare target material.

[0104] The target substrate is made of silicon, and the substrate is covered with an insulating dielectric layer. The insulating dielectric layer is made of silicon oxide, has a thickness of 5000 angstroms, and has a flat top surface.

[0105] S200 , injecting a first ion beam into the injection chamber.

[0106] The parameters of the first ion beam are as follows: the injection gas is argon, and the injection dose is 1*10 16 ion / cm 2 The implantation energy is 50 KeV and the ion beam current is 7 mA. The electron bath device is turned off during the implantation of the first ion beam.

[0107] S300, detecting the number of pollutant particles existing in the implantation chamber of the ion implanter after cleaning.

[0108] Step S300 is the same as the above-mentioned steps S301 to S304 , so as to obtain the increase numbers C1 and C2 of the pollutant particles on the surface of the fake film before and after the detection, where C1 is 66 and C2 is 18.

[0109] After calculation, (C1′-C1)=100, (C2′-C2)=6. It can be seen that Experimental Example 3 can reduce the number of pollutant particles in the implantation chamber of the ion implanter.

[0110] Experimental Example 4

[0111] S000. Detect the number of pollutant particles existing in the implantation chamber of the ion implanter before cleaning.

[0112] Thus, the increase numbers C1′ and C2′ of the contaminant particles on the surface of the fake film before and after the detection are obtained, wherein C1′ is 185 and C2′ is 12. Then, the implantation chamber of the ion implanter is cleaned.

[0113] S100: Prepare target material.

[0114] The target substrate is made of silicon, and the substrate is covered with an insulating dielectric layer. The insulating dielectric layer is made of silicon oxide, has a thickness of 5000 angstroms, and has a flat top surface.

[0115] S200 , injecting a first ion beam into the injection chamber.

[0116] The first ion beam parameters are as follows: the injection gas is argon, the injection dose is 1*1015 ion / cm 2 The implantation energy is 50 KeV, and the ion beam current is 5 mA. The electron bath device is turned off during the implantation of the first ion beam.

[0117] S300, detecting the number of pollutant particles existing in the implantation chamber of the ion implanter after cleaning.

[0118] Step S300 is the same as the above-mentioned steps S301 to S304, so as to obtain the increase numbers C1 and C2 of the pollutant particles on the surface of the fake film before and after the detection, where C1 is 55 and C2 is 6.

[0119] After calculation, (C1′-C1)=130, (C2′-C2)=6. It can be seen that Experimental Example 4 can reduce the number of pollutant particles in the implantation chamber of the ion implanter.

[0120] Experimental Example 5

[0121] S000. Detect the number of pollutant particles existing in the implantation chamber of the ion implanter before cleaning.

[0122] Thus, the increase numbers C1′ and C2′ of the contaminant particles on the surface of the fake film before and after the detection are obtained, wherein C1′ is 147 and C2′ is 13. Then, the implantation chamber of the ion implanter is cleaned.

[0123] S100: Prepare target material.

[0124] The target substrate is made of silicon, and the substrate is covered with an insulating dielectric layer. The insulating dielectric layer is made of silicon oxide, has a thickness of 10,000 angstroms, and has a flat top surface.

[0125] S200 , injecting a first ion beam into the injection chamber.

[0126] The parameters of the first ion beam are as follows: the injection gas is argon, the injection dose is 5*10 15 ion / cm 2 The implantation energy is 100 KeV, and the ion beam current is 5 mA. The electron bath device is turned off during the implantation of the first ion beam.

[0127] S300, detecting the number of pollutant particles existing in the implantation chamber of the ion implanter after cleaning.

[0128] Step S300 is the same as the above-mentioned steps S301 to S304 , so as to obtain the increase numbers C1 and C2 of the pollutant particles on the surface of the fake film before and after the detection, where C1 is 92 and C2 is 16.

[0129] After calculation, (C1′-C1)=55, (C2′-C2)=-3. It can be seen that Experimental Example 5 can reduce the number of pollutant particles in the implantation chamber of the ion implanter.

[0130] Experimental Example 6

[0131] S000. Detect the number of pollutant particles existing in the implantation chamber of the ion implanter before cleaning.

[0132] Thus, the increase numbers C1′ and C2′ of the contaminant particles on the surface of the fake film before and after the detection are obtained, wherein C1′ is 281 and C2′ is 7. Then, the implantation chamber of the ion implanter is cleaned.

[0133] S100: Prepare target material.

[0134] The target substrate is made of silicon, and the substrate is covered with an insulating dielectric layer. The insulating dielectric layer is made of silicon oxide, has a thickness of 5000 angstroms, and has grooves arranged in an array on the top surface of the insulating dielectric layer.

[0135] S200 , injecting a first ion beam into the injection chamber.

[0136] The parameters of the first ion beam are as follows: the injection gas is argon, the injection dose is 5*10 15 ion / cm 2 The implantation energy is 50 KeV and the ion beam current is 4 mA. The electron bath device is turned off during the implantation of the first ion beam.

[0137] S300, detecting the number of pollutant particles existing in the implantation chamber of the ion implanter after cleaning.

[0138] Step S300 is the same as the above-mentioned steps S301 to S304, so as to obtain the increase numbers C1 and C2 of the pollutant particles on the surface of the fake film before and after the detection, where C1 is 98 and C2 is 2.

[0139] After calculation, (C1′-C1)=183, (C2′-C2)=5.

[0140] Experimental Example 7

[0141] S000. Detect the number of suspended pollutant particles existing in the injection chamber of the ion implanter before cleaning.

[0142] Thus, the increase numbers C1′ and C2′ of the contaminant particles on the surface of the fake film before and after the detection are obtained, wherein C1′ is 85 and C2′ is 18. Then, the implantation chamber of the ion implanter is cleaned.

[0143] S100: Prepare target material.

[0144] The target substrate is made of silicon, and the substrate is covered with an insulating dielectric layer. The insulating dielectric layer is made of silicon oxide, has a thickness of 8000 angstroms, and has a flat top surface.

[0145] S200 , injecting a first ion beam into the injection chamber.

[0146] The first ion beam parameters are as follows: the injection gas is argon, the injection dose is 1*10 12 ion / cm 2 The implantation energy is 20 KeV, and the ion beam current is 0.015 mA. The electron bath device is turned off during the implantation of the first ion beam.

[0147] S300, detecting the number of suspended pollutant particles existing in the implantation chamber of the ion implanter after cleaning.

[0148] Step S300 is the same as the above-mentioned steps S301 to S304, so as to obtain the increase numbers C1 and C2 of the pollutant particles on the surface of the fake film before and after the detection, where C1 is 73 and C2 is 16.

[0149] After calculation, (C1′-C1)=12, (C2′-C2)=2. It can be seen that Experimental Example 7 can reduce the number of pollutant particles in the implantation chamber of the ion implanter.

[0150] Experimental Example 8

[0151] S000. Detect the number of pollutant particles existing in the implantation chamber of the ion implanter before cleaning.

[0152] Thus, the increase numbers C1′ and C2′ of the contaminant particles on the surface of the fake film before and after the detection are obtained, wherein C1′ is 292 and C2′ is 9. Then, the implantation chamber of the ion implanter is cleaned.

[0153] S100: Prepare target material.

[0154] The target substrate is made of silicon, and the substrate is covered with an insulating dielectric layer. The insulating dielectric layer is made of silicon oxide, has a thickness of 10,000 angstroms, and has grooves arranged in an array on the top surface of the insulating dielectric layer.

[0155] S201 , injecting a second ion beam into the injection chamber.

[0156] The second ion beam parameters are as follows: the injection gas is argon, the injection dose is 4*10 15 ion / cm 2 The injection energy is 100 KeV, and the ion beam current is 7 mA. During the injection of the second ion beam, the electron bath device is turned off, and the second ion beam is injected in four directions, and the angle between the injection direction and the normal line of the groove bottom surface is 7°.

[0157] S202, injecting a first ion beam into the injection chamber.

[0158] The parameters of the first ion beam are as follows: the injection gas is argon, the injection dose is 5*10 15 ion / cm 2 The injection energy is 50 KeV, and the ion beam current is 4 mA. During the injection of the first ion beam, the electron bath device is turned off, and the injection direction of the first ion beam is perpendicular to the bottom surface of the groove.

[0159] S300, detecting the number of pollutant particles existing in the implantation chamber of the ion implanter after cleaning.

[0160] Step S300 is the same as the above-mentioned steps S301 to S304, so as to obtain the increase numbers C1 and C2 of the pollutant particles on the surface of the fake film before and after the detection, where C1 is 57 and C2 is 2.

[0161] After calculation, (C1′-C1)=235, (C2′-C2)=7.

[0162] The relevant parameters of Experiments 1 to 8 are summarized in Table 1. It should be noted that 1E+16 is represented by 1*10 16 , 5E+15 is expressed as 5*10 15 , and the rest is similar. Table 1

[0163] According to Experimental Example 1, when the insulating dielectric layer material is silicon nitride, the values ​​of (C1′-C1) and (C2′-C2) are both relatively obvious, which can produce a good cleaning effect on the ion implanter. Compared with Experimental Example 3, although the ion beam implantation energy of Experimental Example 3 is lower, it may be because there are more particles adhering to the inner wall of the implantation chamber in Experimental Example 3, and the ion beam bombards the contaminant particles on the inner wall to form suspended particles, so that the cleaning effect of the second particle (C2′-C2) of Experimental Example 3 is poor.

[0164] According to Experimental Examples 2 and 3, the injection dose of the first ion beam in Experimental Example 3 is higher, but the value of (C1′-C1) decreases, and the cleaning effect becomes worse. Considering that the adsorption area of ​​the target surface is limited, after a large number of pollutant particles are adsorbed on the target surface, as the injection dose of the first ion beam increases, some pollutant particles will be bombarded down to form suspended pollutant particles, resulting in a deterioration of the cleaning effect.

[0165] According to Experimental Examples 2 and 4, the implantation dose of the first ion beam in Experimental Example 4 is low, the value of (C1′-C1) decreases, and the cleaning effect becomes worse, but the difference is not very large. Combining Experimental Examples 2 to 4, as the single implantation dose of the first ion beam increases, the cleaning effect shows a trend of first increasing and then decreasing.

[0166] According to Experimental Examples 2 and 5, the injection energy of the first ion beam in Experimental Example 5 increases, which increases the probability of the pollutant particles attached to the inner wall of the injection chamber being bombarded, and the number of second particles removed (i.e., the value of C2′-C2) decreases (even to a negative value, i.e., the number of second particles injected into the chamber increases), and the overall number of particles removed (i.e., the value of C1′-C1) decreases, and the cleaning effect becomes worse.

[0167] According to Experimental Example 2 and Experimental Example 6, the cumulative dose of the ion beam injected in Experimental Example 2 and Experimental Example 6 is the same, wherein the insulating dielectric layer in the target material in Experimental Example 6 is provided with grooves, so that the adsorption area of ​​the insulating dielectric layer is increased, and thus the adsorption effect is better.

[0168] According to Experimental Example 7, the insulating dielectric layer in the target material is a flat surface, and it still has a certain cleaning effect even under the conditions of low implantation dose, low implantation energy, and low implantation ion beam.

[0169] According to Experimental Example 8 and Experimental Example 6, the parameters of the first ion beam injected in Experimental Example 8 are the same as the parameters of the first ion beam injected in Experimental Example 6. In Experimental Example 8, a second ion beam with higher injection energy is injected before the first ion beam is injected. The second ion beam with higher injection energy is used to make more pollutant particles attached to the inner wall of the injection cavity fall off and float in the injection cavity. The first ion beam with lower injection energy is used to form more charge accumulation layers on the insulating dielectric layer of the target material, thereby adsorbing the suspended pollutant particles in the injection cavity and enhancing the cleaning effect of the injection cavity.

[0170] The above is only a specific implementation of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present disclosure should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A cleaning method for an ion implanter, characterized in that: include: Placing the target material in an implantation chamber of an ion implanter; A first ion beam is injected into an implantation chamber of an ion implanter to bombard the target material, so as to form a charge accumulation layer on the surface of the target material to adsorb suspended pollutant particles in the implantation chamber.

2. The cleaning method of the ion implanter according to claim 1, characterized in that: Also includes Before injecting a first ion beam bombarding the target material into an implantation chamber of the ion implanter, injecting a second ion beam bombarding the target material into the implantation chamber of the ion implanter; The implantation energy of the second ion beam is greater than the implantation energy of the first ion beam, and the ion beam current of the second ion beam is greater than the ion beam current of the first ion beam.

3. The cleaning method of the ion implanter according to claim 2, characterized in that: An implantation dose of the second ion beam is smaller than an implantation dose of the first ion beam.

4. The cleaning method of the ion implanter according to claim 2, characterized in that: The implantation dose of the first ion beam and / or the second ion beam is 1*10 12 ion / cm 2 Up to 1*10 16 ion / cm 2 and / or, The implantation energy of the first ion beam and / or the second ion beam is less than or equal to 100 KeV; and / or, The implantation energy of the first ion beam and / or the second ion beam is greater than or equal to 20 KeV.

5. The cleaning method of an ion implanter according to claim 1, characterized in that: The target material includes a substrate and an insulating medium layer covering the substrate.

6. The cleaning method of the ion implanter according to claim 5, characterized in that: The insulating dielectric layer has grooves arranged in an array on a side away from the substrate.

7. The cleaning method of the ion implanter according to claim 6, characterized in that: The second ion beam is implanted in multiple directions with angles; and / or, The implantation direction of the first ion beam is perpendicular to the bottom surface of the groove.

8. The cleaning method of an ion implanter according to any one of claims 1 to 7, characterized in that: The cleaning method further comprises: The cleaning result of the ion implanter is detected.

9. The cleaning method of the ion implanter according to claim 8, characterized in that: Detecting the cleaning effect of the ion implanter includes: Measuring the number A1 of first particles and the number A2 of second particles on the surface of the dummy film before the ion beam is injected, wherein the diameter of the first particles is less than or equal to the preset diameter, and the diameter of the second particles is greater than the preset diameter; Placing the dummy film on the table of the ion implanter and implanting a preset ion beam under preset conditions; Take out the dummy film and measure the number B1 of the first particles and the number B2 of the second particles on the surface of the dummy film after the ion beam is injected; Whether the cleaning result meets the standard is determined based on the number A1 and the number A2 of first particles on the dummy film surface before ion beam injection and the number B1 and the number B2 of first particles on the dummy film surface after ion beam injection.

10. The cleaning method of an ion implanter according to claim 9, characterized in that: Determining a cleaning result based on the number A1 of first particles and the number A2 of second particles on the surface of the dummy film before the ion beam is injected and the number B1 of first particles and the number B2 of second particles on the surface of the dummy film after the ion beam is injected includes: If C1 is less than the first preset value, and C2 is less than the second preset value, the cleaning result meets the standard, wherein C1 = (B1 + B2) - (A1 + A2), C2 = (B2 - A2); and / or, If C1 is greater than or equal to the first preset value or C2 is greater than or equal to the second preset value, the cleaning result does not meet the standard, and the first ion beam is re-injected into the implantation chamber of the ion implanter.

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