JPS58106824A - Processing method by focus ion beam - Google Patents

Abstract

PURPOSE:To contrive the reduction of the processing time and then allow to easily vary the ion irradiation amount and the irradiated ion source at different part of the material to be processed, by scanning focus ion beams with diameter larger than the line width of patterns so as to trace said formed resist pattern. CONSTITUTION:Using an electron beam exposure device, the resist 43 is exposed to a desired pattern, and successively the resist 43 is developed resulting in the formation of the resist pattern 45. Next, using a focus ion beam irradiation device, the beam diameter is set much larger than the maximum line width of said resist pattern 45, a beam registration is performed, and thereafter the ion beams (full line arrow X in the figure) are scanned so as to trace the resist pattern 45. Therby, only the part of a thermal oxide film 42 not covered with the resist 43 is etched.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a focused ion beam processing method for implanting ions into a workpiece, etching the workpiece, etc. by irradiating the workpiece with a focused ion beam.

Technical background of the invention and its problems Recently, various phosphorography techniques using ion beams have been attracting attention, and this technique is expected to fundamentally revolutionize semiconductor manufacturing processes in the future. Ion beam lithography can be roughly divided into ion beam resistless lithography that uses a resist and ion beam resistless lithography that does not use a resist. Ion beam renost phosphorography is a method in which a resist/4' turn is usually formed on the workpiece, and then an ion beam is irradiated all at once, and it is used as an alternative technology to electron beam, light, or X-ray soda lithography. , is expected to be put into practical use in the near future. In addition, ion beam resistless lithography is a method in which an ion beam of usually minute dimensions is scanned over a workpiece, and is considered to open up a new field that cannot be replaced by conventional techniques.

However, this type of method has the following problems: In the ion beam resist lithography, the ion beam is irradiated all at once using the resist as a mask, so ions may be applied to different parts of the workpiece. It is not possible to change the irradiation dose (implanted ion concentration), and it is also impossible to implant different ion species. When processing the drain by ion implantation, an astronomical processing time is required. For example,
r) Using an O ion source, beam diameter 0.5 (711
111φ], 4 under the condition of convergent bull top angle (m rad )
It takes more than 30,000 minutes to etch an inch wafer. Furthermore, under the same conditions 81-MoB
) To form the source φ drain of the Ranjis voice, 3
There was a problem in that it took more than 1,000 minutes.

Purpose of the Invention The purpose of the present invention is to solve the problems of the conventional method O mentioned above,
Focused ion technology can significantly shorten the processing time when performing various types of processing using an ion beam, and can easily change the amount of ion irradiation and the type of ion irradiation on different parts of the workpiece. The object of the present invention is to provide a beam processing method.

Summary of the Invention The present invention involves coating a workpiece with an hhv cyst resistant to ion beams, exposing the resist to a desired pattern using light, X-rays, or electron beams, and then developing the resist. A better method is to form a resist/4 turn, and then scan with a large direct @0 focused ion beam (the line width of the pattern) tracing the resist Δp=y.

Effects of the Invention According to the present invention, since an ion beam having a diameter larger than the line width of the Lennost pattern is scanned over the wrinkles/mother turns using a resist as a mask, the diameter of the ion beam can be set to It can be made significantly larger than the diameter of the focused ion beam. Therefore, the beam current can be increased, and the time required for etching, ion implantation, etc. can be significantly shortened compared to the aforementioned ion beam resistless phosphorography.

This will help you improve your throughput. In addition, since ion beam irradiation is not performed all at once, it is possible to avoid the inconvenience of not being able to vary the ion irradiation amount or ion type for different parts of the workpiece, which is the case with the ion beam resist lithography mentioned above. Ru.

Embodiment of the Invention Iris 1 Diagram Line 1 is a schematic configuration diagram showing a FOS ion beam irradiation device used in the method of an embodiment of the present invention.
fi, tungsten/filament for holding and heating liquid metal, Jj/Ii liquid eutectic alloy (811
-As, 681 g-am.

! 411-1'k), 1 adze vlfw, 14
Fi, r lid electrodes, and 1s are ion extraction electrodes, which form an ion gun that emits a minute ion beam. 16 is the ninth blanking electrode that turns the ion beam ON-OFF, 1r is an aperture mask for blanking, a good Einzel lens (condenser lens) that focuses the J#Fi ion beam, zs
'a Vienna Phil J10 mass spectrometer, 20 is an aperture mask for selecting ions, 21 is a good deflector that scans the ion beam on the sample surface, 11
is Einzel's electrostatic lens (objective ring Je),! , 1d81 Sample at wafer cape, 24 is a sample stand that fixedly holds the sample IJ, 26 is a drive converter that moves and drives the sample stand 14, jlij sample stand Sample stand 1 Kasumi0ru*jFU register storage ln The reflected ion detector 28 used is a secondary ion analyzer, and Z* and SO are converters for converting the detected signals of the reflected ion detector 21 and the secondary ion analyzer 280 into digital signals, respectively. . 11 It is a computer that performs various controls, and a zxB interface. J4 is a high-voltage power supply for the ion gun, 15 is a bias voltage generation circuit, sg is an ion extraction power @1110 high-voltage power supply, and sr is a pattern signal generation circuit. 31 is a high-voltage power supply for the condenser lens 18, 1# is the ninth O power supply that generates the electric field and magnetic field for the mass spectrometer 1g, and 40 is the deflector 21.
41 is a high-voltage power source for the objective lens 22.

Since the operation of the focused ion beam irradiation device having such a configuration is substantially the same as that of a well-known electron beam lithography device, a detailed explanation thereof will be omitted.

The nine ions fired from the electron gun are mus", am"
and pHI. From now on, by selecting a predetermined ion beam, for example, only Mut, using the mass spectrometer 19 and the selection armature mask 20, the sample jJKMu ion beam will be irradiated. Then, the ion beam can be blanked on the sample 13 and scanned in nine predetermined directions. In addition,
It is preferable that the ion beam OI can be varied within the range of radial line 1 to 10 (μmφ).

Next, an example in which the above-described focused ion beam irradiation device is used and the present invention is applied to a shelf for fine processing of an oxide film will be described. First, a thermal oxide film 42 is deposited on the <8S wafer 41 as shown in FIG.
An ion beam resist 43 having resistance to ion beams, such as PMMA (II! Remethyl memethacrylate), is applied thereon, and 44 in the figure indicates a reference mark. Using a beam exposure device, expose the Lugist 4J to a desired pattern, and then
3 was developed to form a resist pattern 4J as shown in No.-II (ms) K.

Next, install the well-focused ion beam irradiation device described above.
1 'r''sThe beam diameter is set slightly larger than the maximum line width of the resist/9 turn 4I], and the resist/9
The ion beam (indicated by arrow X in the figure) was scanned so as to trace turn 4J. As a result, as shown in FIG. 2 (@), only the portions of the thermal oxide film 42 that are not treated by the resist 41 can be etched and chipped. The accuracy is high, as the resist nozzle coincides perfectly with the turn Kj, and it should be noted that the ion species used for forming the oxide film 42 is optimally Mr+, and the ion beam The diameter depends on the resist pattern 45, is usually larger than the maximum pattern dimension, and is determined from the i condition in which adjacent patterns are not irradiated with the ion beam.

Thus, according to the present method, it is possible to increase the diameter of the ion beam to about the diameter of the resist/9 turn 45 fastening ring 10 (Iam). The beam current of a focused ion beam of 10 (smφ) is several tens of times smaller than that of a focused ion beam used in normal direct writing.
Since there is no need to consider lens and aberration by increasing the intensity by more than 0 times, it is possible to increase the V-5 intensity by more than 1000 times. As a result, it only takes about 30 minutes to etch a 4-inch wafer and about 3 minutes to form a source/drain, resulting in a significant reduction in processing time. In addition, in the case of engineering, chin r, by real-time analysis of the secondary ion mass spectrometer XaO analysis, the engineering, chin! It turned out that it was possible to confirm the completion.

11 Although K uses a resist, the ion beam is not irradiated all at once, so it is also possible to implant different ion species into the 81 Quaha OA site. IE of 81 way A41 as shown
Injecting ore ions into the IO site 46, the 20th site 4
7 can also be easily implanted with r ions.

t, the original author 011 JIEK is ion species 6A
For example, the LIIIO prototype was produced using multiple devices, such as lf Ar+ ion processing scissor device, ylfJ processing device, and P+ ion processing device. The sloop and torque have improved by more than two orders of magnitude compared to the previous model.
During prototype development, it was found to be extremely effective for prototyping custom LSIs.

It should be noted that the present invention is not limited to the above-mentioned nine embodiments.For example, the layer to be etched is not limited to an oxide film, but may be etched by ion beam irradiation. However, the focused ion beam irradiation device used in the method of the present invention is not limited to the device shown in Figure 1 above, and can be modified as appropriate according to the specifications. Furthermore, it goes without saying that the present invention can also be applied to ion implantation in the etchant, oxide film formation, silinide metal formation, metal film formation, semiconductor film formation, etc.
i. Various modifications may be made without departing from the gist of the invention.

[Brief explanation of drawings]

1st ailtj A schematic configuration diagram showing an example of a focused ion beam irradiation device used in an embodiment method of the present invention, s
FIGS. 2(a) to 2(@) are cross-sectional views showing microfabrication steps related to the method of the above embodiment. 4 J-111 Quafer, 42... thermal oxide film, 43.
・Resist, 44・-Standard! -ri, 45-・Resist-parable turn.

Claims (2)

[Claims] (1) After applying a resist that is resistant to ion beams on the workpiece, apply a desired resist to the above resist using light, X-rays, or electron beams or by soda-fi.
A focused ion beam processing method characterized in that four turns are formed, and then a focused ion beam having a diameter larger than the line width of the pattern is scanned along the main turns of the resist. (2) By scanning the focused ion beam,
2. The focused ion beam processing method according to claim 1, further comprising implanting ions into the workpiece, forming an oxide layer, forming a silicide film, forming a metal film, or etching the workpiece.