JPH01274424A - Mask for phtoelectron transfer - Google Patents

Abstract

PURPOSE:To remove distortion from a transfer pattern and improve accuracy in positioning by forming a silicon oxide film which has almost the same thickness as that of a semiconductor layer at an alignment mark forming part, on a sapphire substrate at a transfer pattern forming area so as to align the heights of the transfer pattern forming area with the alignment mark part. CONSTITUTION:A mask layer is patterned after the formation on a SOS(silicon on sapphire) substrate surface, while the silicon at a transfer pattern forming area is thermally oxidized so as to form a siliconoxide layer 307, and then mask surface for light electron transfer is flattened. Next, a mask pattern 304 is formed on the surface of a silicon oxide layer, and further a photoelectric film 305 consisting of cesium iodide, etc., is formed on a silicon oxide layer 307 that includes this mask pattern 304. On the other hand, an alignment mark 303 is formed, in case of MIS type structure, for example, in such a manner that a thin oxide film and next a metal layer are formed on the whole face of a P-type silicon layer 202 and then the oxide film layer and the metal except the alignment pattern formation part are removed by etching.

Description

[Detailed Description of the Invention] [Summary] The present invention provides MIS/PNN at least in the positioning portion.
Regarding the production of a photoelectron transfer mask having a junkinone structure, the purpose is to provide a photoelectron transfer mask without pattern distortion during exposure, and in an electron beam transfer exposure apparatus, the alignment between a sapphire substrate and the above-mentioned 7-layer substrate is provided. A semiconductor layer formed in a mark formation area, an alignment mark provided in a predetermined area of the semiconductor layer, and an alignment mark provided in a pattern formation area on the sapphire substrate and having substantially the same thickness as the semiconductor layer. It consists of a silicon oxide film and a photoelectronic transfer mask having a transfer pattern provided on the silicon oxide film.

[Industrial application field]

The present invention is applied to an electronic transfer exposure device in the phosphor technology.
Concerning the structure of a child transfer mask having a structure such as an IS-PN junction.

Ultraviolet exposure methods have been used as a lithography technique for a long time.Since then, ultraviolet exposure methods have been repeatedly improved to make patterns finer.
The limit of miniaturization has been pointed out due to the limit of 000A), and techniques such as electron beam exposure method, X-ray exposure method, and photoelectronic transfer method are being considered.

The electron beam m-source method deflects an electron beam with a point-like or rectangular cross section, irradiates it onto the wafer while changing the position tIi, and then moves the stage to draw a fine pattern on the wafer. be. Therefore, the electron source,
In addition to a column system that converges, shapes, and deflects the electron beam, and a stage system that supports the electron beam and changes the exposure position, a control system that controls these is required. This method can hope to improve the resolution, but because it uses a so-called "-*i" g source based on a huge amount of pattern data, it takes time to expose, has a low throughput, and is unproductive. Not suitable for

Further, the X-ray exposure method is a proximity method, in which a large-scale X-ray light source of, for example, 10 to 50 kW is used, and X-rays having a wavelength of 1 to IOA are used. Therefore, in X-ray exposure, in addition to the above-mentioned light source, an aligner is used that supports the mask and wafer and can align them with high precision.
A combination of these is required. In this respect, it is similar to the conventional light exposure method, but the light source is expensive and expensive, the material of the mask must be considered due to the relationship between the absorption coefficient and the light source wavelength, and the ,
As the diameter of the wafer increases, there is a problem in that the mask bends and the mask and wafer warp, resulting in variation in the gap between the mask and the wafer, resulting in blurring.

It is difficult to obtain a strong X-ray reaction, and the throughput is not very good. It has been proposed to use a synchrotron radiation source, in which the X-ray source is strong and parallel light, as the light source for X-ray generation, but the equipment would be complicated and the cost would be enormous. However, it takes time to manufacture and operate the device, and it is difficult to use, so it cannot be said that it is suitable for a practical exposure device.

As an exposure method that takes advantage of both the high throughput of the transfer method and the high resolution of the electron beam exposure method, there is a transfer exposure method using photoelectrons. This exposure method involves patterning a photoelectron-emitting material and a non-emitting material on a mask.
The photoelectrons generated by shining a light on the mask,
Accelerated by the electric field and magnetic field applied between the mask and the Uniha,
This is a method in which the particles are bundled and transferred onto a wafer. As one of the more advanced photoelectronic transfer methods, there is a method of using a mask having a structure as a photoelectronic transfer mask.

The present invention relates to the structure of this well-shaped electronic transfer mask.

[Conventional technology]

Photoelectron transfer technology involves irradiating a photoelectron transfer mask placed parallel to the sample with light (ultraviolet light), and applying 99 electrons excited and emitted from the photoelectron transfer mask to an electric and magnetic field applied between the photoelectric master samples. This technology transfers a desired pattern onto a sample by accelerating and deflecting it.

FIG. 4 shows a conceptual diagram of photoelectronic transfer exposure. The photoelectronic transfer method will be explained below with reference to FIG. In photoelectron transfer exposure, a photoelectron transfer mask 10 and a sample 20 are placed facing each other in parallel at right angles to the magnetic field in a converging coil 51 (parallel hot water created by Helmholtzkoi peeling (vertical direction in the same area)), and the sample 20 Electron beam sensitizer 2 is on the surface of
1 is applied. Then, a potential is applied such that the photoelectric mask 10 becomes negative and the sample 20 becomes positive. The photoelectron transfer mask 10 includes a mask pattern 12 of an ultraviolet absorber made of a metal such as chromium formed on a transparent substrate 11 made of quartz, for example, and a film of a photoelectron emitting material that emits electrons when irradiated with ultraviolet rays on the entire surface. It is made by depositing 13. Cesium iodide (CsI) is usually used as the photoelectron emitting material. However, CsI has problems such as requiring ultraviolet light with a wavelength of 200 nmff1 degree to emit photoelectrons, and CsI itself being deliquescent.In recent years, Ag has been used as a photoelectron emitting material instead of CsI. is proposed.

Ultraviolet light vA that emits ultraviolet light 81 on the back surface of the transparent substrate 11
80 is installed and the photoelectric mask 10 is irradiated with the ultraviolet rays 81. The ultraviolet rays 81 hit the photoelectron emitting material formed in the area where there is no transfer pattern 12 (the area marked ■ in the figure), and photoelectrons 90 are emitted from that area. released like an arrow. The photoelectrons 90 emitted from one point on the photoelectron transfer mask 10 draw a linear flow due to the accelerating voltage applied between the photoelectron transfer mask 10 and the sample 20 and the parallel magnetic field created by the converging coil 51. Proceed in the direction of 20 and sample 2
It gathers again at one point on the surface of 0. The electron beam sensitizer 21 on the surface of the sample 20 is exposed by the i-electrons 90, and the sample 2
The pattern of the photoelectronic transfer mask is transferred onto the photoelectronic transfer mask.

FIG. 5 shows a schematic diagram of the photoelectronic transfer device. Fifth
In Figure (A), there is a photoelectronic transfer mask 10 on the right side of the center.
However, on the left side of the center, silicon wafers 21 are facing each other in parallel. FIG. 5(B) shows a type of device that irradiates light from the surface side of a photoelectronic transfer mask. Here, magnetic pole 2
This gives a parallel magnetic field. A photoemissive material is also patterned onto the mask. A backscattered electron detector (not shown) is formed on the flat plate electrode 7.

The backscattered electron detector detects the electron beam generated when photoelectrons emitted from the alignment mark on the mask hit the alignment mark on the wafer, thereby aligning the charged mask and the wafer. The deflection coil 31 is used when scanning the electron beam emitted from the alignment mark of the electron transfer mask onto the alignment mark on the wafer.

In addition to the above-mentioned mask in which the metal pattern 12, '#, and electric film 13 are formed on the transparent substrate 11, a structure-type transfer mask has been devised as a child transfer mask.

As shown in FIG. 6, this structured transfer mask has a PNN junction structure on a substrate 110 made of quartz or the like (factor 6 (B)), or a silicon oxide layer or the like on a semiconductor layer 100. The metal layer 102 has a structure (MIS structure, FIG. 6(A)) in which the metal layer 102 is adhered. These are usually PN/semiconductor-metal contact: By applying a voltage, electrons in the semiconductor are accelerated and emitted into a vacuum. At this time, when the semiconductor layer portion is irradiated with ultraviolet rays, the semiconductor layer absorbs the light and electrons are more easily excited, so that the amount of electrons emitted into the vacuum increases.

From the metal layer 102 in FIG. 6(A) to FIG.
), electrons are emitted only from above the N-type semiconductor layer 112, so a pattern can be created on the mask. When using this structured transfer mask,
Stable electrons can be obtained, but the emission area is large, so
The release capacity per unit area is not good.

By the way, especially when applying a voltage to a structured transfer mask made of PN resin to emit electrons, the smaller the emitting area is, the more effective the electrons will be emitted because the emitting power per unit area will be the same. Therefore, it is highly preferable to use this voltage application structure as an alignment mark. in this case,
The portion where the pattern to be transferred is drawn, the so-called transfer pattern forming area, may be patterned with a photoelectron emitting material such as CsI Ag and a non-photoelectron emitting material such as tungsten.

[Problem to be solved by the invention]

However, in reality, as mentioned above, if the alignment mark part is structured electron emitting and the transfer pattern forming area is formed with a pattern of a photoelectron emitting material and a non-electron emitting material as shown in FIG. It was a cone. That is, in order to make the alignment mark portion of the photoelectronic transfer mask structured electron emission, in addition to having to form a semiconductor layer on the substrate, ultraviolet rays must pass through the transfer pattern formation area. The substrate must be a transparent substrate. One possible method for forming a semiconductor layer on a transparent substrate is to deposit a semiconductor such as silicon on quartz, but when silicon is actually deposited on quartz, the silicon becomes polycrystalline. I can't get any results. Therefore,
SO8 layered in silicon gold single crystal state on
It is conceivable to use a structural substrate. Such alignment marks can be formed if the thickness of the silicon layer is 2 μm. With the above method, a semiconductor layer can be formed on a transparent substrate. After forming a semiconductor layer on the entire surface of a transparent substrate, a PN jumper is placed on the alignment mark portion, and the semiconductor layer is placed on the transfer pattern forming area. Made of metal etc. on top,
Even if a transfer pattern that absorbs ultraviolet rays and an electron-emitting material are formed on it to realize 7'l+photoelectric mask t-,
There are problems like arrows. That is, as mentioned above, the semiconductor layer such as silicon has a property of absorbing light with a wavelength of about 100911 m or less, and if the semiconductor layer is present in the transfer pattern forming area of the photoelectronic transfer mask,
The ultraviolet rays are absorbed in this part, and the photoelectron emitting material on the photoelectron transfer mask is not irradiated with the ultraviolet rays, so the amount of emitted electrons is reduced. To solve this problem, the semiconductor layer is made thinner.

Alternatively, a possible solution is to remove the semiconductor layer in the transfer pattern forming area, but when growing a thin semiconductor layer on a sapphire substrate, there are too many defects to make it usable up to a certain thickness.

Therefore, a photoelectronic transfer mask in which the semiconductor layer in the pattern forming area is removed is considered to be a promising method. FIG. 3 shows a schematic cross-sectional view of a photoelectronic transfer mask having this structure. This photoelectronic transfer mask is made of silicone skin 202t-
After etching the transferred pattern forming area 206 of the etched layer 202 on the attached sapphire substrate 201, a mask pattern 204 made of ester/gelstone etc. is formed in the transferred pattern forming area 206, and the mask pattern is A photoelectric film 205 made of CsI, λg, etc. is formed on the transfer pattern forming area 206 including the top of 204.
Form a passle. The mask pattern 204 may be formed in the silicon layer 202, and the remaining silicon layer will have alignment marks formed with PA or MI8 structure metal. By using the photoelectron transfer mask shown in the third factor, the alignment mark portion can be configured to emit structured electrons, and the transfer pattern forming area can be configured by a pattern made of a photoelectron emitting material and a non-photoelectron emitting material. However, even with this configuration, there are still problems. That is, in the photoelectronic transfer mask shown in FIG.
6 and the height of the alignment mark forming area are different from each other, causing electrical distortion in the transfer pattern forming area and distorting the pattern. Furthermore, alignment accuracy also decreases.

In view of the above points, it is an object of the present invention to provide a photoelectronic transfer mask that does not cause pattern distortion during exposure even when the transfer pattern forming area is of a transmission type and the alignment mark-shaped bottom area is of a structure. [Means for Solving All]] The above problem is caused by the difference in height between the transfer pattern bottom area and the alignment mark forming area in the photoelectronic transfer mask. The above-mentioned problem is solved by forming silicon oxide on the substrate to have a thickness that is almost the same as the thickness of the semiconductor layer in the alignment mark forming area, and making the heights of the transfer pattern existing area and the alignment mark area the same. I can do it.

That is, the present invention provides an electron beam transfer VT source device including:
a semiconductor IfI formed in an alignment mark forming area on the sapphire substrate, an alignment mark provided in a predetermined area of the semiconductor layer, and a transfer pattern forming area on the seventh ear substrate. The semiconductor device is characterized by comprising a silicon oxide film provided in the semiconductor layer and having a thickness substantially concave with the semiconductor layer, and a photoelectronic transfer mask having a transfer pattern formed on the silicon oxide film.

[For production]

According to the present invention, the transfer pattern forming area of the photoelectronic transfer mask is increased by the thickness of the silicon oxide film and is approximately at the same height as the bottom of the alignment mark shape, so pattern distortion is less likely to occur than in the past. , the alignment is also improved by n degrees. In addition, the silicon oxide film can sufficiently transmit wavelengths that excite photoelectrons, just like the 7-layer substrate. can be released.

[Example] FIG. 1 shows a schematic cross-sectional view of a mask for transferring a single element according to the present invention. As shown in FIG. 1, this photoelectronic transfer mask consists of a sapphire substrate 301, silicon #302 formed in the alignment mark forming portion on the seven ear substrates 301, Table 1, and a predetermined portion of the silicon 1%1. Alignment marks 303 made of a PN junction or MIS structure provided in the area and predetermined areas on the transfer pattern forming area silicon fluoride layer 307 on the surface of the sapphire substrate 301 are formed to absorb ultraviolet rays such as ultraviolet rays such as ungsten. A mask pattern 304 consisting of a body, and the mask pattern 30
The film 305 is made of cerium iodide, silver, etc., and is formed on the silicon oxide layer 307 including the surface of the silicon oxide layer 307.

When performing electron beam transfer exposure using this photoelectron transfer mask, first align mark 3030PN yank 7M
A voltage is applied between the metal and semiconductor layers of the MIS structure to emit electrons from the surface of the alignment mark 303, and alignment is performed based on this. The substrate (Itll) is irradiated with ultraviolet rays 1. After passing through the substrate 301 and the silicon oxide layer 307, the ultraviolet rays reach the transfer pattern forming area.

Here, the ultraviolet rays of the mask pattern 3040 are absorbed by the mask pattern. On the other hand, the photoelectric film 305 is irradiated with ultraviolet rays in areas where there is no mask pattern, and electrons are excited and emitted from this photoelectric film, and these electrons are accelerated and deflected by the electric field and magnetic field between the photoelectron transfer mask and the sample. reach. In this way, the transfer pattern of the mask can be transferred to the sample.

FIG. 2 shows a top view of the manufacturing process of a photoelectronic transfer mask according to the present invention. The photoelectronic transfer mask of the present invention is
As shown in FIG. 2 (8) to (D), as a mask substrate,
Using an SO8 (Si) qcon On 5apphire) substrate, either by thermally oxidizing the silicon in the transfer pattern formation area, or by selectively oxidizing it, or by ion-implanting oxygen atoms into the area, a sapphire substrate can be formed. - Even if the silicon interface part is oxidized, it can be formed by (1) removing the 7 silicon from the above-mentioned part and then forming a silicon oxide layer by a method such as a CVD method.

That is, FIG. 2 (person) shows an example of the manufacturing process of the first photoelectronic transfer disk, and first, FIG. 2 (A) (a)
After forming a mask layer (not shown) made of photoresist, silicon oxide, silicon nitride, etc. on the surface of the SO8 substrate as shown in Fig.
As shown in (b), the silicon in the transfer pattern forming area is thermally oxidized to form a silicon oxide layer 307. Next, as shown in FIGS. 2(A) and 2(C), the surface of the photoelectronic transfer mask is flattened using the Volitanog technique or the like.

Finally, as shown in FIGS. 2(A) and 2(d), an ultraviolet absorber made of tungsten or the like is deposited on the surface of the silicon oxide layer using a sputtering technique or the like, and then an unnecessary portion t-
The mask pattern 30 is removed using anisotropic edging or the like.
A photoelectric film 305 made of cesium iodide or the like is further formed on the silicon oxide layer 307 including the mask pattern 304. On the other hand, the alignment mark 303 is
In the case of PN junk construction, for example, P-type silicon 7
Doping gold such as boron onto a predetermined region of the 1302 surface (
(For example, by ion implantation) V) Form a P-type silicone layer, and then form υN-type silicon i'ii- by doping phosphorus, arsenic, etc. in a predetermined region of the P-type silicone layer. . After forming a protective silicon dioxide film on the surface, annealing is performed to activate the implanted impurity ions, and finally the silicon dioxide layer is removed. Also, MIS
In the case of a type structure, it can be formed, for example, by forming a thin oxide film and then a metal layer over the entire surface of the P-type silicon layer 302, and then etching away the oxide film layer and the metal layer other than the matching pattern formation area. The manufacturing process of the mask pattern and alignment mark is common to all manufacturing methods, and the order of whether the alignment mark forming process is performed before or after the formation of the silicon oxide layer 307 does not matter.

FIG. 2(B) shows an example of the manufacturing process of the second photoelectronic transfer mask. In this way, first, see Figure 2 CB)
<a) As shown in FIG.
After step 2, as shown in Figure 2 (CB) (b), the transfer pattern formation area is covered with a mask layer (not shown), and then silicon is epitaxially grown only in the alignment mark formation area to make it thicker than the transfer pattern formation area. A silicon layer 302' is formed.As shown in FIGS. 2(B) and 2(c), the alignment mark forming area is covered with a mask layer (not shown) made of photoresist or the like, and then the transfer pattern forming area is covered with a mask layer (not shown) made of photoresist or the like. The silicon is thermally oxidized and the mask layer is removed.At this time, the thickness of the silicon/1i 302' and the silicon oxide layer 307 are made to be almost the same.Finally, as shown in FIG. ), a mask pattern 304 and 3051 ft of photoelectric film are formed in the transfer pattern forming area to complete the photoelectron transfer mask.

FIG. 2(C) shows an example of the manufacturing process of the third photoelectronic transfer mask. In this method, Fig. 2(c)
A mask layer (not shown) made of photoresist or the like covers the area other than the transfer pattern formation area of the SO8 substrate shown in (a).
After coating with , oxygen atoms are selectively ion-implanted into the transfer pattern forming area. Then, the silicon in the transfer pattern forming area is oxidized at the interface between the silicon substrate and the silicon layer, and a silicon oxide layer 307 is formed on the surface with 2 remaining on the silicon, as shown in FIGS. 2(c) and 2(b). be done.

Finally, the silicon layer remaining on the surface of the transfer pattern formation area is polished or etched.
Remove the oxidized silicone layer 307 and silicon Ji30.
After flattening the photoelectronic transfer mask 2, a mask pattern 304 and a photoelectric film 305 are formed in the transfer pattern forming area as shown in 219th (C) and (C), and the photoelectronic transfer mask is exposed. Second
In the manufacturing process shown in FIG. 2(c), P and N junctions are selectively applied to the silicon layer without removing the silicon layer remaining on the transfer pattern forming area, as shown in FIGS. 2(c) and 2(c'). It is also possible to form a structured photoelectronic transfer mask by forming a carbon or MIS structure.

FIG. 4(D) shows an example of the manufacturing process of the fourth photoelectronic transfer mask. In this method, first, Figure 2 (D)
After covering the alignment mark forming area on the surface of the SO8 substrate as shown in (a) with a mask layer (not shown) made of photoresist or the like, anisotropic etching is performed and the etching is performed as shown in FIG.
) As shown in (b), the silicon in the transfer pattern forming area is removed. A silicon oxide layer 302 having approximately the same thickness as the silicon layer 302 of the alignment mark portion is formed on the surface of the transfer pattern forming region by chemical vapor deposition.

Finally, as shown in FIG. 2(D)(d), a mask pattern 304 is placed on the surface of the transfer pattern forming area, and the original film 30
5 to complete the photoelectronic transfer mask.O The embodiment of the photoelectronic transfer mask has been described above, but even in a manufacturing process other than the above, it is possible to form the silicon layer of the alignment mark part on the bottom area of the transfer pattern shape. Any method may be used as long as it can selectively form a silicon oxide layer with substantially the same thickness.

〔Effect of the invention〕

As explained above, according to the present invention, there is no difference in height between the alignment mark portion of the photoelectron beam transfer mask and the transfer pattern area, so the potential drop in the mask is eliminated and the transferred pattern is distorted. is gone. In addition, the accuracy of alignment was the same as above.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a photoelectronic transfer mask according to the present invention, FIG. 2 is a cross-sectional view of the manufacturing process of a photoelectron transfer mask according to the present invention, and FIG. 3 is a schematic cross-sectional view of a conventional photoelectronic transfer mask. , FIG. 4 is a conceptual diagram of photoelectronic transfer exposure, FIG. 5 is a schematic diagram of a photoelectronic transfer apparatus, and FIG. 6 is a schematic diagram of the weight of a structured transfer mask. Also, 1 is a chamber, 2 is a magnetic pole, 4 is an XY stage, 5
1 is a mask stage, 6 is an exhaust port, 7 is a flat electrode, 8 is a power source, 10 is a mask for photoelectronic transfer, 11 is a transparent substrate, 1
2,204,304 are mask patterns, 13,205,
305 is a photoelectron, 20 is a sample, 21 is an electron beam sensitizer, 31 is a polarizing coil, 51 is a focusing coil, 80 is an ultraviolet source, 81 is an ultraviolet ray, 90 is a photoelectron, Zoo is a semiconductor layer,
101 is an insulating layer, 102 is a metal layer, 110 is a substrate, 111 is an HP type semiconductor layer, 112 is an N-type semi-quadruple layer, 20
1,301 is a sapphire substrate, 202,302,302
' is the silicon layer, 203° 303 is the matching mark, 206
, 306 is a transfer pattern forming area, 307 is silicon oxide/ml, 308 is P type Si, g, 309 is N type S
il-meetings are shown respectively. First cross-sectional view of the photoelectronic transfer mask according to the invention
Figure (A) Photoelectronic transfer mask according to the invention; cross-sectional view of the manufacturing process of the second plate 4 Schematic diagram of a conventional photoelectronic transfer mask Fig. 3 Photoelectronic transfer exposure pot Fig. 2 Schematic diagram of the photoelectronic transfer device Schematic diagram of the Taya circuit diagram of the pattern transfer mask Figure 6

Claims (1)

[Scope of Claims] A pattern on the photoelectron transfer mask is formed by applying light from the back side of the photoelectron transfer mask and accelerating and focusing the photoelectron beam excited and emitted from the photoelectron transfer mask using an electric field and a magnetic field. In an electron beam transfer exposure apparatus for transferring onto a wafer, the photoelectron transfer mask includes: a substrate that transmits light; a semiconductor layer formed in an alignment mark forming area on the substrate; and a predetermined area of the semiconductor layer. an alignment mark provided on the substrate; a light transmission layer provided in a pattern formation area on the substrate and having substantially the same thickness as the semiconductor layer; and a transfer pattern provided on the light transmission layer. Features of photoelectronic transfer mask.