JPS5854633A - Microprocessing method - Google Patents

Abstract

PURPOSE:To reduce fog caused by the back scattering of an electron beam and to form a high-accuracy minute pattern by a method wherein a high-density conductive film is formed on a processed body and a sensitive electron resist is formed on the film. CONSTITUTION:A high-density conductive film 13 controlling the penetration of electrons is formed on a processed body 12 and a sensitive electron resist 14 is formed on the film 13. Next, the resist 14 is exposed with a desired pattern and developed by using electron beams accelerated at 7-15keV. Dry etching is applied to the film 13 by using the resist 14 as a mask and then, dry etching is applied to the processed body 12 by using the film 13 as a mask. Therefore, the back scattering of an electron beam can extremely be reduced and sufficient exposure is also applied to the resist. Therefore, a decrease in resolving power caused by back scattering can be prevented and a pattern with a thickness of several mum or less can be formed with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in microfabrication methods using electron beams.

2. Description of the Related Art Recently, a microfabrication method using electron beam exposure technology has been used to form fine heptad turns on semiconductor wafers, mask substrates, and the like. Unlike light exposure technology, electron beam exposure technology does not reduce resolution due to diffraction, and is said to be essentially capable of easily forming fine f-turfs. However, the electron beam has another factor limiting the ls image power, called scattering in solids, and this
m) The following - parable turn formation has become a serious problem.

FIG. 1 is a schematic diagram showing an electron beam exposure method related to a conventional microfabrication method. An electron-sensitive resist (J) is coated on the workpiece 2 formed above the substrate 1, and the resist (J) is irradiated with an electron beam accelerated to, for example, 20 (K@V) to form a desired /f Turn to Russia. Next, the resist J is developed, and then the workpiece 2 is etched using the resist J as a mask to form a -arm turn.

Here, the substrate 1 is silicon, and the workpiece 2 has a thickness of O, S (μ
m] silicon oxide, Resost 3Yr thickness 1 [cotton] p
-French (polymethylmethac 1 route), the electron beam reaches a depth of several [μ] within the substrate 1, and is backscattered from that depth. This backscattered electron is res)J
When K re-enters the resist 1, it causes the so-called capri phenomenon.The range of this capri reaches several [μm] K, regardless of the diameter of the electron beam.And when resist J is developed, the capri causes the so-called capri phenomenon. The dimensional accuracy of the resist turn was impaired, and it was not possible to form a diameter turn with a number of p or less with high precision.

Therefore, the above-mentioned backscatter II! An attempt has been made to reduce the energy of the electron beam as a means to reduce the energy of the electron beam.If the sum of O energies is less than 5 (K@V), the penetration depth of the electron beam is extremely small9, and backscattering is The area covered is also small, and there is no support 1iI in the formation of ffnkuron. However, in this case, since the penetration depth of the electron beam is small, a problem arises in that the entire area of the resist 1 cannot be sufficiently exposed. Also, if the energy of the electron beam is set to 10 (K@V) and 9, s 2
Although a better result can be obtained than in the case of 0 (K@V),
It wasn't satisfying.

The present invention was developed in consideration of the above circumstances, and its purpose is to reduce the capri caused by the backward sensitivity LK of the electron beam, to sufficiently expose the resist, and to
The object of the present invention is to provide a microfabrication method that can form turns with high precision.

First, the aS of the present invention will be explained. If the acceleration voltage of the electron beam is set to 7 (K@V) or less, sufficient exposure of the resist is impossible as described above. Therefore, the acceleration voltage of the electron beam needs to be 7 (K@V) or more. Also, VB
In materials with a high density, the penetration depth of electrons becomes shallower, and the range of backscattering becomes narrower. Ninth, if a material with a certain high density is formed to a certain thickness or more, the penetration of electrons can be suppressed. According to research by the present inventors, a conductive film with a density of 10 or more is D [μm
] It was found that when formed to a thickness greater than 1, the penetration of electron beams of 15 (K@V) or less is suppressed to a factor of 11.

The present invention has focused on these points, and after forming a high-density conductive film on the workpiece and forming an electrosensitive resist on the conductive film, it is accelerated to 7 to l5 (K@V). The resist is exposed to a desired number of turns using an electron beam, and then developed. Then, using the resist as a mask, the conductive film is subjected to a dry etching process, and then the workpiece is subjected to a dry etching process using a conductive film mask as a mask. This is the method I used to do it.

Therefore, according to the present invention, backscattering of the electron beam can be extremely reduced, and the resist can be sufficiently exposed. For this reason, it is possible to prevent the resolution from decreasing due to the backscattering mentioned above, and to reduce the number of Od turns below Jl!I.
The jin that forms in a beautiful way comes. - As an example, as shown in the second mK, the thickness of the resist 30 is 1 [JllI], and the g thickness t O, l of the conductive film 4 made of platinum (density 214 t/d)
(s sea bream) and exposed it with an electron beam of accelerated electric current fE 1 G (K@V) (9 and ζ). It became smaller.

In the case of to, it was possible to expose with high precision an I-tar ν having a dimension of l [μm3. Further, as the workpiece 2, an insulator t! When there is fI, the conductor 1114 visits the charger f caused by the electron beam, and there are advantages such as being able to prevent distortion of the z4 turn. In microfabrication, ion beam etching, reactive ion beam etching, and reactive etching are usually used.

Although dry etching such as Chin-R is used, the % conductive film can be sufficiently used as a mask material for Dry etching and Chin-R.

The details of the present invention will be explained below with reference to illustrated embodiments. I will clarify.

Figure 3-) to (dJ are molds related to one example of the present invention.
/e A cut-and-return model showing the turn forming process.

Mass, JllIS tllJklK show ft1J < y
9 w y group 1i: I l A silicon oxide film 12 as a workpiece is formed on the silicon oxide film 12 by 0.5 [μ] using thermal oxidation technology.
Platinum II (conductive film) JJtO,1 (μ
Then, K Pliil was formed on the platinum film 13 to a thickness of
! MA resist 14 was spin-coated to a thickness of 1 [μ], and then an electron beam was used to apply an accelerating voltage of 10 (K@V).
Under the condition of a dose amount of 60 (Ja/j), the resist 141
1C1, 2e4, each turn of 10 (ms) was exposed. Followed by inzolopanol and methylinbutylketone.

When the resist 14 is developed with the mixed solution, a rennost-natern pattern as shown in FIG. 3 is formed.

In addition, in Figure 3), the above 1 (μ groove) and 2 [μ groove] (D
I! It shows the developed state of the party section.

Next, as shown in FIG. 3 (@), using an aluminium ion beam and a chlorine gas, with the resist 14 as a mask, platinum I Platinum 11JJ as shown in Section 8111(d) using reactive ionization and ching techniques as a reactive gas.
The silicon region 1s11 is processed and etched using as a mask.
No. 10 (Kishi-purchased), all dimensions had good accuracy.

Note that although a silicon substrate was used in the above embodiment, a glass substrate may be used instead, and the present invention can also be applied to the production of a 7t) mask in which the workpiece is chromium or the like.

In addition, the conductive film is not limited to a platinum film, but is a material with high density, preferably a material with a density of 10 or more and a film thickness of
It is sufficient if the material is υ [cotton] or more. Furthermore, the material and film thickness of the workpiece and lenost may be determined as appropriate depending on the specifications, without departing from the gist of the present invention.
-, it is possible to transform the shape and execute it.

[Brief explanation of the drawing]

Figure ia1 is a schematic diagram showing the conventional electron beam exposure method related to microfabrication method, and figure w42 is a schematic diagram of Akira Motokinuti's principle! I! For clarity, FIGS. 3(1) to 3(d) are schematic diagrams showing the process of forming fine and circular turns according to an embodiment of the present invention. 11・Axis silicon group'l, J x・-Silicon 11 compound 1
[(Workpiece), IS...Platinum II (Conductivity II), 1
4-・Resist. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2

Claims (1)

[Claims] a) Elevated position (ic@
v) A step of exposing the resist to a desired p4 turn using an electron beam f:MJ accelerated by MJ, and then developing the resist using the resist as a mask.
1. A microfabrication method comprising the steps of dry etching the workpiece, and then dry etching the workpiece using the conductive film as a mask. Q) The microfabrication method according to claim 1, wherein the conductive film has a density Di-10 or more and a film thickness of D C μm1 or more. (3) The microfabrication method according to claim 1 or 182, wherein tantalum, platinum, gold, or a composite thereof is used as the conductive film.