CN114256045B - Method for improving metal pollution of ion implanter - Google Patents
Method for improving metal pollution of ion implanter Download PDFInfo
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- CN114256045B CN114256045B CN202111541428.3A CN202111541428A CN114256045B CN 114256045 B CN114256045 B CN 114256045B CN 202111541428 A CN202111541428 A CN 202111541428A CN 114256045 B CN114256045 B CN 114256045B
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- ion
- metal pollution
- set threshold
- metal
- threshold value
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- 229910052751 metal Inorganic materials 0.000 title claims abstract description 65
- 239000002184 metal Substances 0.000 title claims abstract description 65
- 238000000034 method Methods 0.000 title claims abstract description 24
- 238000010884 ion-beam technique Methods 0.000 claims abstract description 35
- 238000005468 ion implantation Methods 0.000 claims abstract description 27
- 238000012360 testing method Methods 0.000 claims abstract description 12
- 238000000605 extraction Methods 0.000 claims description 10
- 238000011109 contamination Methods 0.000 claims description 7
- HAYXDMNJJFVXCI-UHFFFAOYSA-N arsenic(5+) Chemical group [As+5] HAYXDMNJJFVXCI-UHFFFAOYSA-N 0.000 claims description 4
- 229910052710 silicon Inorganic materials 0.000 abstract description 13
- 239000010703 silicon Substances 0.000 abstract description 13
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 abstract description 11
- 239000000758 substrate Substances 0.000 abstract description 5
- 150000002500 ions Chemical class 0.000 description 52
- 235000012431 wafers Nutrition 0.000 description 22
- 239000012535 impurity Substances 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 5
- 238000004458 analytical method Methods 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 4
- 238000000576 coating method Methods 0.000 description 4
- 230000005684 electric field Effects 0.000 description 4
- 238000002347 injection Methods 0.000 description 4
- 239000007924 injection Substances 0.000 description 4
- 230000033001 locomotion Effects 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- 230000001133 acceleration Effects 0.000 description 2
- 238000013459 approach Methods 0.000 description 2
- WTEOIRVLGSZEPR-UHFFFAOYSA-N boron trifluoride Chemical compound FB(F)F WTEOIRVLGSZEPR-UHFFFAOYSA-N 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 239000002784 hot electron Substances 0.000 description 2
- 238000002513 implantation Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000005086 pumping Methods 0.000 description 2
- 150000003376 silicon Chemical class 0.000 description 2
- 229910015900 BF3 Inorganic materials 0.000 description 1
- 229910052785 arsenic Inorganic materials 0.000 description 1
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011982 device technology Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000005672 electromagnetic field Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/30—Electron-beam or ion-beam tubes for localised treatment of objects
- H01J37/317—Electron-beam or ion-beam tubes for localised treatment of objects for changing properties of the objects or for applying thin layers thereon, e.g. for ion implantation
- H01J37/3171—Electron-beam or ion-beam tubes for localised treatment of objects for changing properties of the objects or for applying thin layers thereon, e.g. for ion implantation for ion implantation
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
- H01J2237/02—Details
- H01J2237/022—Avoiding or removing foreign or contaminating particles, debris or deposits on sample or tube
Landscapes
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Physical Vapour Deposition (AREA)
Abstract
The invention provides a method for improving metal pollution of an ion implanter, which comprises the steps of placing the ion implanter in an air-conditioner state, wherein the ion implanter comprises a machine chamber and an ion implantation device arranged in the machine chamber; placing the ion implanter in an air-conditioner state; bombarding the machine cavity by utilizing ion beam current generated by the ion implantation device, performing ion implantation on the bare wafer by utilizing the ion implantation device, and performing metal pollution content test to obtain metal pollution content data; providing a set threshold value, and comparing the metal content pollution data with the set threshold value; and if the metal pollution content data is larger than the set threshold value, comparing the metal pollution content data with the set threshold value until the metal pollution content data is smaller than the set threshold value. The method can purify the internal environment of the machine, reduce the metal content to be within the specification, and can not damage the silicon substrate tissue structure when the contact type image sensing device product is manufactured.
Description
Technical Field
The invention relates to the technical field of semiconductors, in particular to a method for improving metal pollution of an ion implanter.
Background
CIS (Contact Image Sensor) is a contact image sensing device. The device adopts a contact type photosensitive element (photosensitive sensor) for photosensitive, 300-600 red, green and blue LED (light emitting diode) sensors are tightly arranged at the position of 1-2 mm below a scanning platform to generate a white light source. The scanner manufactured by the contact type image sensing device technology has the advantages of small volume, light weight, low production cost and the like, and is widely applied to the fields of fax machines, scanners, banknote sorting and blending zero and the like.
In the field of semiconductor manufacturing, metal pollution greatly affects the product of a contact type image sensing device, if excessive metal is injected into a wafer in the ion injection process, the structure of a silicon substrate can be damaged, WAT (wafer acceptance test) and the yield are affected, and a white spot effect is generated on the product, so that the product is invalid; therefore, in the daily production of FAB, the clamping control of the metal pollution of the machine is important; since the implanter is made of metal, a lot of metal adheres to various locations inside the tool during maintenance and cleaning of the tool.
Therefore, how to purify the internal environment of the machine, to reduce the metal content to be within the specification, is a precondition for manufacturing the contact image sensing device product, and the prior art can only reduce the metal at the contact position, and can not remove the metal at the position on the side wall of the cavity and the beam path quickly, so that a method is needed for improving the metal pollution of the ion implanter.
Disclosure of Invention
In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a method for improving metal contamination of an ion implanter, which is used for solving the problems in the prior art that in the field of semiconductor manufacturing, metal contamination greatly affects a contact image sensing device product, and if too much metal is implanted into a wafer during ion implantation, the structure of a silicon substrate is damaged, WAT is affected, and white spot effect is generated on the product, resulting in failure.
To achieve the above and other related objects, the present invention provides a method for improving metal contamination of an ion implanter, comprising:
Step one, providing an ion implanter, and placing the ion implanter in an air-conditioner state, wherein the ion implanter comprises a machine chamber and an ion implantation device arranged in the machine chamber; placing the ion implanter in an air-machine state;
bombarding the machine cavity by utilizing ion beam current generated by the ion implantation device, so that the side wall surface of the machine cavity is covered by the high-energy ion beam current;
Performing ion implantation on the bare wafer by using the ion implanter to obtain a metal pollution test wafer, and then performing metal pollution content test on the metal pollution test wafer to obtain metal pollution content data;
step four, providing a set threshold value of the metal pollution content of the required wafer, and comparing the metal content pollution data with the set threshold value;
and fifthly, if the metal pollution content data is larger than the set threshold, repeating the second to fourth steps, and repeating the second to third steps, and comparing the metal pollution content data with the set threshold until the metal pollution content data is smaller than the set threshold. Preferably, the ion implantation apparatus in the first step includes an ion source and an extraction electrode.
Preferably, the method for generating an ion beam current by using the ion implantation apparatus in the second step is as follows: increasing the voltage of the extraction electrode increases the energy of the ion beam current.
Preferably, the ion beam current in the second step is a high-energy high-current ion beam current.
Preferably, the current value of the ion beam current is 15mA to 17mA.
Preferably, the ion beam in the second step is arsenic ion beam.
Preferably, the time of said bombardment in step two is one hour.
Preferably, the ion implantation time in the third step is 2 hours.
Preferably, the set threshold in the fourth step is E10 atom/cm2.
As described above, the method for improving metal contamination of an ion implanter of the present invention has the following advantageous effects:
The invention purifies the internal environment of the machine, reduces the metal content to be within the specification, does not damage the structure of the silicon substrate when the contact image sensing device product is manufactured, and improves the quality of ion implantation.
Drawings
FIG. 1 is a schematic illustration of the process flow of the present invention;
FIG. 2 is a schematic diagram of a process for cleaning a chamber of a machine in the prior art;
FIG. 3 is a graph showing the failure rate of the present invention compared with the prior art.
Detailed Description
Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention.
Referring to fig. 1, the present invention provides a method for improving metal contamination of an ion implanter, comprising:
Step one, providing an ion implanter, wherein the ion implanter in the prior art consists of 5 parts in sequence: ion source, ion extraction and mass analysis magnetic field, accelerating tube, injection system, and process chamber.
Ion source:
The ion implanter bombards gas molecules with hot electrons generated by a filament in an ion source under the action of an electric field to ionize the gas molecules. The impurity source to be injected can be directly introduced into the electric field of the ion source if the impurity source is in a gaseous state, and is also required to be heated and evaporated if the impurity source is in a solid state, and then is introduced into the electric field after being changed into a gas phase. The impurity source in the gas phase becomes ions (i.e., charged atoms or molecules) upon ionization in an electric field.
Ion extraction and mass analysis magnetic field:
All positively charged ions are extracted from a slit by positive pressure repulsion of the anode of the ion source, at which time electrons in the plasma are repelled by the cathode, thereby forming an ion beam of positive ions. The hot electrons bombard the impurity source gas molecules to generate a plurality of ions, such as boron trifluoride gas source, which are formed in the ion source, and each ion has a different mass to charge ratio, and the trajectories of the ions are different when passing through the analyzing magnet of the mass analyzing magnetic field, which can separate the desired impurity ions from the mixed ion beam.
Accelerating tube:
To obtain greater energy for the ions, positive ions are forced out of the mass analysis field and then passed through the high pressure of the acceleration tube to achieve the desired velocity. The accelerating tube is composed of a series of dielectric isolated electrodes, and negative voltages on the electrodes are sequentially increased. When positive ions enter the accelerating tube, the negative electrodes accelerate the ions, the movement speed of the ions is the superposition of the acceleration of each stage, and the higher the total voltage is, the faster the movement speed of the ions is, namely the larger the kinetic energy is.
Injection system:
The implantation system of the ion implanter forms relative motion between the ion beam and the silicon wafer, so that impurities on the silicon wafer are uniformly distributed, unrecoverable damage caused by overheating of a point of the ion bombarded local part for a long time is avoided, and the ion implantation of the silicon wafer adopts a scanning mode. There are two basic scanning modes: mechanical scanning and electromagnetic scanning. The mechanical scanning adopts a method of moving the silicon wafer, namely, a circular turntable drives the silicon wafer to move. Electromagnetic scanning is the scanning achieved by deflecting an ion beam with an electromagnetic field. Some injectors use a hybrid approach, i.e., a combination of mechanical and electromagnetic approaches.
The process chamber comprises the following steps:
The process chamber comprises a circular turntable for placing silicon wafers, an injection system, a silicon wafer loading and unloading terminal platform with a vacuum lock, a silicon wafer transmission system and a computer control system.
In production, the inner wall of the machine chamber is easy to form a metal covering layer, the ion implanter is placed in an empty state, the machine can be kept or shut down, the ion implanter comprises a machine chamber and an ion implantation device arranged in the machine chamber, the inner wall of the machine chamber is formed with the metal covering layer, and the machine chamber can comprise a chamber where an ion source, an ion extraction and mass analysis magnetic field and the like are located;
in one possible embodiment, the ion implantation device in step one comprises an ion source and an extraction electrode for ion extraction.
Referring to fig. 2, the conventional method for FAB includes: the wafer is loaded, the first pre-pumping machine chamber, the orientation of the orientation device, the fixation of the pressing plate and the ion implantation are carried out, and the cyclic operation of the second side pre-pumping machine chamber is carried out, so that the metal in the machine is taken away and the specification is reached; the common conveying can only reduce the metal at the contact position, the metal at the position on the side wall of the cavity and the beam path can not be removed quickly, and in order to improve the metal removing effect of the side wall of the cavity, the ion implantation device is used for generating ion beam to bombard the machine cavity, so that the side wall of the machine cavity is covered by the ion beam;
in one possible embodiment, the ion beam in the second step is a high energy, high current ion beam.
In one possible embodiment, the method for generating the ion beam current by using the ion implantation device in the second step is as follows: increasing the voltage of the extraction electrode increases the energy of the ion beam stream, analyzed from the implantation regime: ion beam power = ion beam current x ion beam energy (P = I x U), the higher the energy, the greater the ion beam power, with the ion beam current unchanged; the ion beam can remove the metal coating on the machine part from the source end to the end, and the metal coating is formed by the metal for manufacturing the ion implanter, thereby playing the role of purifying the machine.
In one possible embodiment, the current value of the ion beam current is 15mA to 17mA.
In one possible embodiment, the ion beam in the second step is arsenic ion beam, and arsenic is in the fourth cycle, V A groups, and has an atomic number of 33, and the arsenic ion has a larger mass and a higher removal capacity for the metal coating than the ion in the ion source commonly used in the prior art.
In one possible embodiment, the bombardment in step two is one hour, and the metal coating on the machine part can be removed.
Performing ion implantation on the bare wafer by using an ion implanter to obtain a metal pollution test wafer, and then performing metal pollution content test on the metal pollution test wafer to obtain metal pollution content data;
In one possible embodiment, the ion implantation in the third step is performed for 2 hours, and the bare wafer is ion implanted.
And step four, providing a set threshold value of the metal pollution content of the required wafer, and comparing the metal content pollution data with the set threshold value.
In one possible embodiment, the metal contamination level of the desired wafer is set at a threshold of E10 atoms/cm 2, which has less impact on ion implantation.
And fifthly, if the metal pollution content data is larger than the set threshold value, repeating the second to fourth steps, and repeating the second to third steps, and comparing the metal pollution content data with the set threshold value until the metal pollution content data is smaller than the set threshold value.
In one possible embodiment, referring to fig. 3, in the bar graphs in the original condition and the current condition, the left bar graph is the number of tests, the right bar graph is the number of failures, the failure rate in the original condition is 31%, and the failure rate of the ion implanter after being cleaned in this way is 8%.
It should be noted that, the illustrations provided in the present embodiment merely illustrate the basic concept of the present invention by way of illustration, and only the components related to the present invention are shown in the drawings and are not drawn according to the number, shape and size of the components in actual implementation, and the form, number and proportion of the components in actual implementation may be arbitrarily changed, and the layout of the components may be more complex.
In summary, the invention purifies the internal environment of the machine, reduces the metal content to be within the specification, does not damage the tissue structure of the silicon substrate when the contact image sensing device product is manufactured, and improves the quality of ion implantation. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.
The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.
Claims (3)
1. A method of ameliorating metal contamination of an ion implanter comprising at least:
Step one, providing an ion implanter, wherein the ion implanter comprises a machine chamber and an ion implantation device arranged in the machine chamber, and the ion implantation device comprises an ion source and an extraction electrode; placing the ion implanter in an air-machine state;
bombarding the machine cavity by utilizing ion beam current generated by the ion implantation device, wherein the ion beam current is arsenic ion beam, the current value of the ion beam current is 15mA to 17MA, and increasing the voltage of the extraction electrode increases the power of the ion beam current so that the ion beam current covers the surface of the machine cavity;
Performing ion implantation on the bare wafer by using the ion implanter to obtain a test wafer, and then performing metal pollution content test on the test wafer to obtain metal pollution content data;
Step four, providing a set threshold value of the metal pollution content of the required wafer, wherein the set threshold value is E10 atom/cm < 2 >, and comparing the metal pollution content data with the set threshold value;
and fifthly, if the metal pollution content data is larger than the set threshold, repeating the second to fourth steps until the metal pollution content data is smaller than the set threshold.
2. The method of claim 1, wherein the method further comprises: the time of the bombardment in step two was 1 hour.
3. The method of claim 1, wherein the method further comprises: the ion implantation time in the third step was 2 hours.
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| CN202111541428.3A CN114256045B (en) | 2021-12-16 | 2021-12-16 | Method for improving metal pollution of ion implanter |
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| CN202111541428.3A CN114256045B (en) | 2021-12-16 | 2021-12-16 | Method for improving metal pollution of ion implanter |
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| CN114256045A CN114256045A (en) | 2022-03-29 |
| CN114256045B true CN114256045B (en) | 2024-06-18 |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105097460A (en) * | 2014-05-09 | 2015-11-25 | 中芯国际集成电路制造(上海)有限公司 | Method for solving problem of path pollution of ion implanter |
| CN112908876A (en) * | 2021-01-18 | 2021-06-04 | 上海新昇半导体科技有限公司 | Silicon chip metal pollution testing method and device |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5554854A (en) * | 1995-07-17 | 1996-09-10 | Eaton Corporation | In situ removal of contaminants from the interior surfaces of an ion beam implanter |
| KR100241695B1 (en) * | 1997-03-10 | 2000-02-01 | 윤종용 | Wafer pollution prevention apparatus of ion implanter |
| CN103151281B (en) * | 2011-12-07 | 2015-11-25 | 无锡华润上华科技有限公司 | A kind of monitoring method of ion implantation technology |
| US9524849B2 (en) * | 2013-07-18 | 2016-12-20 | Varian Semiconductor Equipment Associates, Inc. | Method of improving ion beam quality in an implant system |
| CN105742305A (en) * | 2016-04-07 | 2016-07-06 | 上海华力微电子有限公司 | Method for reducing metal contamination introduced in ion implantation of CMOS image sensor |
| CN106373846B (en) * | 2016-11-16 | 2019-01-18 | 上海华力微电子有限公司 | A kind of wafer high energy implanters metallic pollution ameliorative way |
| CN107579027B (en) * | 2017-09-06 | 2020-10-16 | 上海华力微电子有限公司 | Method for monitoring tungsten metal pollution of ion implanter |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105097460A (en) * | 2014-05-09 | 2015-11-25 | 中芯国际集成电路制造(上海)有限公司 | Method for solving problem of path pollution of ion implanter |
| CN112908876A (en) * | 2021-01-18 | 2021-06-04 | 上海新昇半导体科技有限公司 | Silicon chip metal pollution testing method and device |
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