CN113539803A - Batch type ion implantation method - Google Patents
Batch type ion implantation method Download PDFInfo
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- CN113539803A CN113539803A CN202110719090.XA CN202110719090A CN113539803A CN 113539803 A CN113539803 A CN 113539803A CN 202110719090 A CN202110719090 A CN 202110719090A CN 113539803 A CN113539803 A CN 113539803A
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- 238000005468 ion implantation Methods 0.000 title claims abstract description 134
- 238000000034 method Methods 0.000 title claims abstract description 97
- 238000002513 implantation Methods 0.000 claims abstract description 66
- 229920002120 photoresistant polymer Polymers 0.000 claims abstract description 21
- 230000006641 stabilisation Effects 0.000 claims description 2
- 238000011105 stabilization Methods 0.000 claims description 2
- 230000007547 defect Effects 0.000 abstract description 8
- 238000002347 injection Methods 0.000 abstract description 7
- 239000007924 injection Substances 0.000 abstract description 7
- 230000000694 effects Effects 0.000 abstract description 4
- 239000002245 particle Substances 0.000 abstract description 4
- 238000004519 manufacturing process Methods 0.000 abstract description 3
- 239000004065 semiconductor Substances 0.000 abstract description 3
- 235000012431 wafers Nutrition 0.000 description 29
- 150000002500 ions Chemical class 0.000 description 28
- 239000007943 implant Substances 0.000 description 7
- 238000010943 off-gassing Methods 0.000 description 7
- 238000000605 extraction Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 230000000087 stabilizing effect Effects 0.000 description 2
- 230000001154 acute effect Effects 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- 238000010884 ion-beam technique Methods 0.000 description 1
- 238000001259 photo etching Methods 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/26—Bombardment with radiation
- H01L21/263—Bombardment with radiation with high-energy radiation
- H01L21/265—Bombardment with radiation with high-energy radiation producing ion implantation
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Abstract
The application discloses a batch type ion implantation method, and relates to the field of semiconductor manufacturing. The method comprises the steps of conveying a wafer into a process chamber of a batch ion implanter, wherein the surface of the wafer is coated with photoresist; carrying out first-step ion implantation on the wafer, so that the photoresist releases gas and the gas pressure in the process chamber is in a preset range; when the air pressure in the process chamber of the batch ion implanter meets the air pressure stability condition, carrying out the second step of ion implantation on the wafer; the beam current during the first step of ion implantation is smaller than the beam current during the second step of ion implantation, the implantation dosage during the first step of ion implantation is smaller than the implantation dosage during the second step of ion implantation, and the sum of the implantation dosage during the first step of ion implantation and the implantation dosage during the second step of ion implantation is equal to the target dosage; the problems that multiple injection interruptions easily occur when the existing batch ion implantation machine is used for single injection, the productivity is influenced, and the product defect risk is increased are solved; the effects of reducing the ion implantation time and improving the particle defects are achieved.
Description
Technical Field
The application relates to the field of semiconductor manufacturing, in particular to a batch type ion implantation method.
Background
An ion implantation process, which is one of the key processes in semiconductor manufacturing, is performed on an ion implanter. The ion implantation process must be completed within a specified vacuum range, and when the vacuum in the implantation process chamber exceeds the specified range, the ion implanter stops the process and continues the process after the vacuum in the implantation process chamber returns to the specified range. The wafer with the photoresist generates and releases a large amount of gas in the early stage of ion implantation, so that the vacuum of the implantation process chamber exceeds the specified range.
Batch ion implanters can process multiple wafers per batch, such as 13 wafers (8 "GSD series), and the problem of outgassing during ion implantation and interruption of implantation is particularly acute in batch ion implanters. When the photoresist percentage on the wafer surface reaches more than 80%, the single implantation process may generate 40 to 100 implantation interruptions due to vacuum problems in the process chamber.
Too many implant interruptions can lead to 2 problems: 1. the interruption causes the increase of the process time and influences the productivity; 2. too many interruptions result in too many mechanical movements of the Faraday (Faraday) component, increasing the particle risk.
Disclosure of Invention
In order to solve the problems in the related art, the present application provides a batch type ion implantation method. The technical scheme is as follows:
in one aspect, an embodiment of the present application provides a batch-type ion implantation method, including:
transferring the wafer into a process chamber of a batch ion implanter, wherein the surface of the wafer is coated with photoresist;
carrying out first-step ion implantation on the wafer, enabling the photoresist on the surface of the wafer to release gas, and enabling the air pressure in a process chamber of the batch ion implanter to be within a preset range;
when the air pressure in the process chamber of the batch ion implanter meets the air pressure stability condition, carrying out the second step of ion implantation on the wafer;
the beam current during the first step of ion implantation is smaller than the beam current during the second step of ion implantation, the implantation dose during the first step of ion implantation is smaller than the implantation dose during the second step of ion implantation, and the sum of the implantation dose during the first step of ion implantation and the implantation dose during the second step of ion implantation is equal to the target dose.
Optionally, the implantation energy of the first step of ion implantation is the same as the implantation energy of the second step of ion implantation.
Alternatively, the air pressure stabilizing condition is that the air pressure reaches a predetermined pressure for a predetermined time.
Optionally, the pressure in the process chamber of the batch ion implanter is monitored during the first and second ion implantations.
Optionally, the implantation dose in the first step of ion implantation is 5% of the target dose, and the implantation dose in the second step of ion implantation is 95% of the target dose.
Optionally, the beam current during the first step of ion implantation is 1mA to 2 mA.
Optionally, when the first step ion implantation and the second step ion implantation are performed, gas in the process chamber of the batch ion implanter is pumped out through the pump set.
The technical scheme at least comprises the following advantages:
the wafer coated with the photoresist is conveyed into a process chamber of a batch ion implanter, first-step ion implantation is carried out on the wafer, the photoresist on the surface of the wafer releases gas, the air pressure in the process chamber of the batch ion implanter is within a preset range, when the air pressure in the process chamber of the batch ion implanter meets a preset stable condition, second-step ion implantation is carried out on the wafer, the beam current during the first-step ion implantation is smaller than the beam current during the second-step ion implantation, the implantation dosage during the first-step ion implantation is smaller than the implantation dosage during the second-step ion implantation, and the sum of the implantation dosage of the first-step ion implantation and the implantation dosage of the second-step ion implantation is equal to a target dosage; the small beam is adopted during the first step of ion implantation, and the large beam is adopted during the second step of ion implantation, so that the interruption of the implantation of the machine in the ion implantation process is avoided, and the problems that the multiple times of implantation interruption easily occur during the single-channel implantation of the conventional batch ion implantation machine, the productivity is influenced, and the product defect risk is increased are solved; the effects of reducing the ion implantation time and improving the particle defects are 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 flowchart of a batch-type ion implantation method according to an embodiment of the present disclosure.
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.
Referring to fig. 1, a flow chart of a batch-type ion implantation method according to an embodiment of the present application is shown, the method at least includes the following steps:
Before ion implantation of a wafer, defining an ion implantation area on the surface of the wafer through a photoetching process; the photoresist coated wafer is transferred into a process chamber of a batch ion implanter and the wafer is transferred onto a target plate.
In the early stage of wafer adhesive injection, photoresist outgassing is severe, outgassing speed is higher than air extraction speed of the process chamber, so that air pressure in the process chamber is increased, and if the air pressure in the process chamber exceeds a preset range, ion injection is interrupted.
The predetermined range is predetermined and is determined according to process conditions of the ion implantation process. The predetermined range is a pressure range that ensures that the batch ion implanter will perform the ion implantation process properly.
Because the implantation dose of ion implantation is calculated by the charge quantity of ions, if the vacuum in the ion implantation process chamber is poor, the ion beam collides with gas molecules in the chamber, and part of ions can obtain or lose electrons in the collision process, so that the calculated implantation dose is inaccurate, and the ion implantation effect is influenced. Therefore, it is desirable to control the vacuum range within the process chamber.
Generally, an upper vacuum limit for the initial implantation and an upper vacuum limit during the implantation are set. When preparing to carry out ion implantation, detecting whether the vacuum value in the process cavity is smaller than the upper vacuum limit of initial implantation, if the vacuum value in the process cavity is detected to be smaller than the upper vacuum limit of the initial implantation, starting the ion implantation, and monitoring the vacuum value in the process cavity in the ion implantation process; if the vacuum value in the process cavity is greater than the upper vacuum limit in the implantation process in the ion implantation process, stopping the ion implantation until the vacuum value in the process cavity is again less than the upper vacuum limit of the initial implantation, and continuing the ion implantation; and if the vacuum value in the process chamber is smaller than the upper vacuum limit in the implantation process in the ion implantation process, continuing to perform the ion implantation.
In one example, the upper vacuum limit for the initial implant is 3E-5torr and the upper vacuum limit during the implant is 8E-5 torr.
The larger the beam current of the ion implantation is, the faster the photoresist outgassing speed is, the smaller the beam current is, the slower the photoresist outgassing speed is, so that in order to avoid the interruption of the implantation, the single-step ion implantation is improved into the step-by-step ion implantation, and in the first-step ion implantation process, the beam current during the ion implantation is reduced, so that the air pressure in the process chamber at the early stage of the glue implantation is kept within a preset range.
And 103, when the air pressure in the process chamber of the batch ion implanter meets the air pressure stability condition, performing the second step of ion implantation on the wafer.
The ion implantation process is not interrupted by the step-by-step ion implantation, and the ion implantation in each step is distinguished by switching the process parameters of the ion implantation in the ion implantation process.
When the outgassing speed of the photoresist and the pumping speed of the process chamber reach balance, the air pressure in the process chamber is stable, and the second step of ion implantation is carried out on the wafer.
The air pressure stabilization condition is preset.
The beam current during the first step of ion implantation is smaller than the beam current during the second step of ion implantation, the implantation dose during the first step of ion implantation is smaller than the implantation dose during the second step of ion implantation, and the sum of the implantation dose during the first step of ion implantation and the implantation dose during the second step of ion implantation is equal to the target dose.
The target dose of the ion implantation is preset according to the process requirements.
When the second step ion implantation is performed, the gas release speed is reduced compared with the gas release speed during the first step ion implantation, the gas release amount of the photoresist is also greatly reduced, and the gas release speed and the gas extraction speed can be balanced in the second step ion implantation process, so that large beam injection is adopted.
In summary, in the batch ion implantation method provided in the embodiment of the present application, the wafer coated with the photoresist is transferred into the process chamber of the batch ion implanter, a first step of ion implantation is performed on the wafer, so that the photoresist on the surface of the wafer releases gas, the gas pressure in the process chamber of the batch ion implanter is within a predetermined range, when the gas pressure in the process chamber of the batch ion implanter meets a predetermined stable condition, a second step of ion implantation is performed on the wafer, the beam current during the first step of ion implantation is smaller than the beam current during the second step of ion implantation, the implantation dose during the first step of ion implantation is smaller than the implantation dose during the second step of ion implantation, and the sum of the implantation dose of the first step of ion implantation and the implantation dose of the second step of ion implantation is equal to a target dose; the small beam is adopted during the first step of ion implantation, and the large beam is adopted during the second step of ion implantation, so that the interruption of the implantation of the machine in the ion implantation process is avoided, and the problems that the multiple times of implantation interruption easily occur during the single-channel implantation of the conventional batch ion implantation machine, the productivity is influenced, and the product defect risk is increased are solved; the effects of reducing the ion implantation time and improving the particle defects are achieved.
In an alternative embodiment based on the embodiment shown in fig. 1, the implantation energy of the first step ion implantation is the same as the implantation energy of the second step ion implantation.
In an alternative embodiment based on the embodiment shown in fig. 1, the air pressure stabilizing condition is that the air pressure reaches a predetermined pressure for a predetermined time.
The predetermined pressure and the predetermined time are preset.
Optionally, the predetermined pressure is a certain pressure range or a certain pressure value, and the predetermined pressure is within the predetermined range. The predetermined range is determined according to process conditions of the ion implantation process.
In one example, the steady state pressure condition is a pressure less than 5E-5torr for 30 seconds.
In an alternative embodiment based on the embodiment shown in fig. 1, the gas pressure within the process chamber of the batch ion implanter is monitored while the first and second ion implantations are performed.
And in the ion implantation process, monitoring the air pressure in the process chamber of the batch ion implanter, and determining the time for performing the second step of ion implantation according to the monitored air pressure.
In an alternative embodiment based on the embodiment shown in fig. 1, the gas in the process chamber of the batch ion implanter is pumped out by a pump set during the first and second ion implantations.
During ion implantation, due to photoresist outgassing, to ensure that the gas pressure within the process chamber of a batch ion implanter is within a predetermined range, it is necessary to evacuate the process chamber.
In one example, the implantation dose in the first step of ion implantation is 5% of the target dose, and the implantation dose in the second step of ion implantation is 95% of the target dose.
In one example, the beam current during the first ion implantation step is 1mA to 2 mA.
In one example, the parameters of a single implantation process for a conventional batch type ion implantation are shown in table 1:
TABLE 1
| Ion source | Implantation energy | Dose of implant | Size of beam current |
| As+ | 80KeV | 6E15ions/cm-2 | 7mA |
In the single-step implantation process shown in table 1, the number of implantation interruptions reaches several tens, and the average implantation time per wafer batch is 1h17min02 s.
By using the method provided by the embodiment of the application, the batch type ion implantation is improved into 2-step ion implantation, and the process parameters of each step of ion implantation are shown in table 2:
TABLE 2
During the step implant shown in table 2, there was almost no implant interruption and the average implant time per lot was 1h02min55 s. Compared with the prior single-step injection, the injection time is reduced by 18.3 percent. In addition, the grain defects generated during the step implantation are also improved over the grain defects generated during the single step implantation.
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 (7)
1. A batch-type ion implantation method, comprising:
conveying a wafer into a process chamber of a batch ion implanter, wherein the surface of the wafer is coated with photoresist;
carrying out first-step ion implantation on the wafer, enabling the photoresist on the surface of the wafer to release gas, and enabling the air pressure in a process chamber of the batch ion implanter to be within a preset range;
when the air pressure in the process chamber of the batch ion implanter meets the air pressure stability condition, performing the second step of ion implantation on the wafer;
the beam current during the first step of ion implantation is smaller than the beam current during the second step of ion implantation, the implantation dose during the first step of ion implantation is smaller than the implantation dose during the second step of ion implantation, and the sum of the implantation dose during the first step of ion implantation and the implantation dose during the second step of ion implantation is equal to the target dose.
2. The method of claim 1, wherein the implantation energy of the first ion implantation step is the same as the implantation energy of the second ion implantation step.
3. The method of claim 1 or 2, wherein the atmospheric pressure stabilization condition is an atmospheric pressure reaching a predetermined pressure for a predetermined time.
4. A method according to any one of claims 1 to 3, wherein the pressure in the process chamber of the batch implanter is monitored during the first and second ion implantations.
5. The method of claim 1, wherein the implantation dose in the first step of ion implantation is 5% of the target dose, and the implantation dose in the second step of ion implantation is 95% of the target dose.
6. The method of claim 1, wherein the beam current during the first step of ion implantation is 1mA to 2 mA.
7. The method of claim 1 wherein gas is pumped out of the process chamber of the batch ion implanter during the first and second ion implantations.
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|---|---|---|---|
| CN202110719090.XA CN113539803A (en) | 2021-06-28 | 2021-06-28 | Batch type ion implantation method |
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| CN202110719090.XA CN113539803A (en) | 2021-06-28 | 2021-06-28 | Batch type ion implantation method |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4851691A (en) * | 1982-11-19 | 1989-07-25 | Varian Associates, Inc. | Method for photoresist pretreatment prior to charged particle beam processing |
| CN101000870A (en) * | 2006-01-13 | 2007-07-18 | 北京中科信电子装备有限公司 | Method and device for controlling ion implantation |
| CN102751182A (en) * | 2011-04-17 | 2012-10-24 | 中国科学院微电子研究所 | Method for manufacturing semiconductor |
| CN103367126A (en) * | 2012-03-28 | 2013-10-23 | 无锡华润上华科技有限公司 | Ion implantation method |
| CN107993931A (en) * | 2017-11-30 | 2018-05-04 | 上海华力微电子有限公司 | The method for improving implanter production efficiency |
| CN109830431A (en) * | 2019-01-08 | 2019-05-31 | 上海华虹宏力半导体制造有限公司 | Improve the process of target disc formula ion implantation apparatus injection efficiency |
-
2021
- 2021-06-28 CN CN202110719090.XA patent/CN113539803A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4851691A (en) * | 1982-11-19 | 1989-07-25 | Varian Associates, Inc. | Method for photoresist pretreatment prior to charged particle beam processing |
| CN101000870A (en) * | 2006-01-13 | 2007-07-18 | 北京中科信电子装备有限公司 | Method and device for controlling ion implantation |
| CN102751182A (en) * | 2011-04-17 | 2012-10-24 | 中国科学院微电子研究所 | Method for manufacturing semiconductor |
| CN103367126A (en) * | 2012-03-28 | 2013-10-23 | 无锡华润上华科技有限公司 | Ion implantation method |
| CN107993931A (en) * | 2017-11-30 | 2018-05-04 | 上海华力微电子有限公司 | The method for improving implanter production efficiency |
| CN109830431A (en) * | 2019-01-08 | 2019-05-31 | 上海华虹宏力半导体制造有限公司 | Improve the process of target disc formula ion implantation apparatus injection efficiency |
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