JPH0794386A - Transmission mask for charged beam exposure and its manufacture thereof - Google Patents

Abstract

PURPOSE:To reduce the number of manufacturing processes and to provide a transmission mask with a sufficient effect for preventing the electrification and overheat of the transmission mask and its manufacturing method. CONSTITUTION:In a transmission mask 10 for exposing charge beam which is manufactured by using a silicon substrate where a support silicon substrate 1 and an upper silicon substrate 3 are laminated, a thin film 2 according to at least one type of metal thin film or an alloy is provided as an intermediate layer for laminating the support silicon substrate 1 and the upper silicon substrate 3 on either one opposing inner surface or both opposing inner surfaces of both silicon substrates.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent mask for charged beam exposure (hereinafter referred to as a transparent mask) and a method for manufacturing the same, and more specifically, a transparent mask having a high transfer accuracy by a charged beam and a manufacturing process as compared with a conventional method. The present invention relates to a method for manufacturing a small number of transmission masks.

[0002]

2. Description of the Related Art A typical method of manufacturing a conventional transmission mask will be described with reference to FIG. First, as shown in FIG. 1A, a supporting silicon (Si) substrate 12 and an upper silicon (Si) substrate 1 on which an insulating layer 13 is formed by thermal oxidation or the like.
An Si substrate 15 is prepared by bonding the No. 4 and the No. 4 by heat bonding or the like, and the upper Si substrate 14 is polished and thinned to a predetermined thickness of the transmission hole. Next, as shown in FIG. 3B, silicon nitride (SiN) is formed on the front and back surfaces of the bonded Si substrate 15.
After depositing a film or the like to form the mask layers 16 and 16, the support S is formed by dry etching or the like as shown in FIG.
The mask layer 16 on the back surface of the i substrate 12 is etched to form an opening pattern 17.

Next, as shown in FIG.
After etching the substrate 14 to form the transmission hole portion 18,
As shown in FIG. 6E, the supporting Si substrate 12 in the opening is potassium hydroxide (KOH) using the mask layer 16 as a protective layer.
The opening hole 19 is formed by etching with an aqueous solution or the like.
Thereafter, as shown in FIG. 3F, the mask layer 16 is removed and the insulating layer 13 is etched to form the through hole 20. Finally, as shown in FIG. 3G, a conductive layer 21 is formed on the upper Si substrate 14 by sputtering or the like to obtain a transmission mask for charged beam exposure.

[0004]

As described in FIG. 5, the conventional method of manufacturing a transmission mask is the supporting Si substrate and the upper Si.
An insulating film such as silicon dioxide (SiO ₂ ) and a semiconductor thin film such as silicon carbide (SiC) are used as an etching stop layer of a supporting Si substrate for forming an opening and an intermediate layer for bonding with the substrate. In addition, there is a danger that the charging and overheating of the transmission mask may seriously affect the transfer accuracy due to the irradiation of the charged beam, and in order to avoid it, the conductive layer was formed separately, but the sufficient effect is not always obtained. However, the number of manufacturing steps was increased as shown in the figure.

The present invention has been made in view of the above conventional problems, and an object thereof is to reduce the number of manufacturing steps and to have a sufficient effect for preventing charging and overheating of the transmission mask and its manufacture. To provide a method.

[0006]

In order to achieve the above object, in a transmission mask for charged beam exposure, which is produced by using a silicon substrate in which a supporting silicon substrate and an upper silicon substrate are bonded together, the supporting silicon substrate and the upper part Charge beam exposure, characterized in that, as an intermediate layer for bonding silicon substrates, at least one kind of metal thin film or alloy thin film is provided on either one or both inner surfaces of both silicon substrates. It is a transparent mask, and uses a thin film of metal or alloy having high conductivity and high thermal conductivity, which can be solid-phase bonded to silicon (Si) by pressure bonding, heating, ultrasonic vibration, etc. as an intermediate layer, In addition, this metal thin film or alloy thin film is used as the etching stop layer of the supporting silicon substrate for forming the opening hole, and The etching rate ratio of the metal or alloy to select the desired on sufficiently low etching conditions.

Further, in a transmission mask for charged beam exposure, which is produced by using a silicon substrate obtained by bonding a supporting silicon substrate and an upper silicon substrate, as an intermediate layer for bonding the supporting silicon substrate and the upper silicon substrate. A method for producing a transmission mask for charged beam exposure, comprising bonding a thin film of at least one kind of metal thin film or alloy with a thin film of the metal thin film or alloy and silicon by solid phase adhesion.

Further, as a method of bonding the supporting silicon substrate and the upper silicon substrate, solid-phase adhesion of metal thin films or alloy thin films or metal thin films and alloy thin films formed on opposite inner surfaces of both silicon substrates. Is a method of manufacturing a transmission mask for charged-beam exposure using.

The present invention will be described in more detail below with reference to the drawings.

FIG. 1 is a side view showing a transmission mask in an embodiment of the present invention. FIG. 2 is a side view showing a transmission mask according to another embodiment of the present invention.

FIG. 3 is a side view showing a method of manufacturing a transmission mask according to the present invention in the order of steps.

First, as shown in FIG. 3, a supporting Si substrate 1
A thin film 2 of metal thin film or alloy on the surface of
A film is formed by a sputtering method or the like ((a) in the same figure). Next, the upper Si substrate 3 is thinned by polishing to a predetermined thickness of the through hole, and the supporting Si substrate 1 on which the metal thin film 2 is formed.
Are solid-phase bonded by a method such as pressure bonding, heating, ultrasonic vibration, etc. ((b) of the same figure).

Next, a SiN film or the like is deposited on the back surface of the bonded Si substrate 4 by a sputtering method or the like to form a mask layer 5 for etching the Si substrate 1 for forming an opening (see FIG. )). After that, a resist is applied to the back surface side of the Si substrate 1 to form a resist pattern in the opening of the transmission mask by means such as ordinary photolithography, and then the mask layer 5 is used as a mask for the reactive ions. Etching is performed by means such as etching, and then the resist pattern is removed to remove Si.
An opening pattern 6 for etching protection of the substrate is formed (FIG. 7D).

Next, a resist is applied to the surface of the upper Si substrate 3, and a resist pattern 7 is formed in a portion to be a transmission hole of the charged beam of the transmission mask by means of ordinary photolithography or electron beam lithography. Figure (e)). Next, using the resist pattern 7 as a mask, the upper Si substrate 3 is etched by means such as reactive ion etching. After that, the resist pattern 7 is peeled off to form a portion of the surface of the upper Si substrate 3 which becomes the transmission hole 8 for the charged beam. A Si pattern is formed ((f) in the same figure).

Furthermore, the mask layer 5 is used as a protective layer to support Si.
The substrate 1 is etched with a KOH aqueous solution, a hydrazine aqueous solution, or the like to form the opening holes 9 (FIG. 6G). After that, by removing the metal thin film or the thin film 2 made of an alloy remaining on the bottom of the transmission hole, the target transmission mask 10 for charged-beam exposure can be obtained ((h) in the same figure).

FIG. 4 is a side view showing a method of manufacturing a transmission mask according to another method of the present invention.

First, thin films 2 and 11 made of a metal thin film or an alloy are formed on the inner surfaces of the supporting Si substrate 1 and the upper Si substrate 3 by a vapor deposition method, a sputtering method, or the like (FIG. 9A). Next, after the upper Si substrate 3 is polished to a predetermined thickness of the through hole to be thinned, the metal film surface of the upper Si substrate 3 and the metal film surface of the supporting Si substrate 1 are brought into contact with each other, and pressure bonding, heating, Solid-phase adhesion is performed by a method such as sonic vibration (FIG. 2 (b)). The subsequent steps are the same as in the case of FIG.

[0018]

In the method of the present invention, as described above, the same layer is used as the etching stop layer of the supporting Si substrate 1 for bonding the supporting Si substrate 1 and the upper Si substrate 3 and for forming the intermediate layer and the opening hole. Since the metal thin film or the thin film 2 made of an alloy is used, it is not necessary to newly form the conductive layer 21 for preventing electrification after peeling the mask layer 16 as in the conventional case, and the number of steps is reduced and the yield is improved. Further, in the transmission mask 10 of the present invention, since the intermediate layer between the supporting Si substrate 1 and the upper Si substrate 3 is not the conventional insulating film 13 but the metal thin film 2 having a large thermal conductivity or the alloy thin film 2, the charged beam It is possible to suppress excessive temperature rise due to irradiation,
The deterioration of the transfer accuracy due to the thermal deformation of the transparent mask is reduced.

[0019]

EXAMPLES The present invention will be described more specifically below with reference to examples.

<Example 1> On the surface of a Si wafer substrate having a 3-inch diameter of 500 μm and a plane orientation of <100>, which is the supporting Si substrate 1, a thickness of 2000 Å was obtained by an electron beam heating vapor deposition method.
A gold (Au) film was deposited. Next, the inner surface of the upper Si substrate 3 polished to a thickness of 20 μm and the supporting Si substrate 1
The Au film surface was subjected to pressure bonding in an ambient temperature of 400 ° C. for solid phase adhesion.

Next, a 1000 N thick SiN film was deposited on the back surface of the bonded Si substrate 4 by a sputtering method to form a mask layer 5 for etching the Si substrate for forming openings. Then, a photoresist microposit (MP) 1400-27 is formed on the back surface of the Si substrate.
Is applied, and a resist pattern of a portion to be an opening hole of a transmission mask is formed by exposure to ultraviolet rays of 40 mJ / cm ² , and then the SiN layer is CF ₄ with the resist pattern as a mask
Etching was performed by reactive ion etching with gas plasma, and then the resist pattern was peeled off to form an opening pattern 6 for etching protection of the Si substrate.

Next, a thickness of 5 μm is formed on the surface of the upper Si substrate 3.
Photoresist MP1400-37 of No. 1 was applied, and the transmission hole pattern on the photomask was transferred and formed by a normal photolithography means. The exposure amount of ultraviolet rays at this time was 300 mJ / cm ² . Next, using the resist pattern as a mask, the Si substrate was etched by an ECR (electron cyclotron resonance) ion beam etching apparatus to a depth of 20 μm. At this time, the etching gas used was chlorine (Cl ₂ ) containing 10% of SF ₆ , and the microwave output was 200 W. After that, the resist was removed by oxygen (O ₂ ) plasma to form a Si pattern of the transmission holes 8 on the surface of the Si substrate.

Next, using the etching protection opening pattern 6 as a mask, 50% hydrazine (N ₂ H) at 110 ° C. is used.
₄ ) The Si substrate was etched with the aqueous solution. Although the hydrazine aqueous solution anisotropically etches Si similarly to the KOH aqueous solution, since Au is hardly etched, it was possible to form a membrane by leaving only the Au film in the transmission holes 8. After that, the Au film remaining at the bottom of the transmission hole was removed while cleaning, and the transmission mask 10 having the structure shown in FIG. 1 was completed.

Example 2 First, a 2000 Å-thickness SiC film was formed on the surface of a Si wafer substrate having the same specifications as in Example 1 as the supporting Si substrate 1 by the sputtering method.
Next, an Au film having a thickness of 1000 Å is formed on the surface of the Si wafer substrate having a 3-inch diameter of 500 μm and a plane orientation of <100> to be the upper Si substrate 3 by the electron beam heating vapor deposition method, and then the thickness of 20 μm is obtained. Polished. After that, support Si
The SiC film surface of the substrate and the Au film surface of the upper Si substrate were pressure bonded at room temperature and subjected to ultrasonic vibration for solid phase adhesion.

Next, an opening pattern 6 for etching protection of the Si substrate is formed on the back surface side of the Si substrates bonded by the same method as in the first embodiment, and is further transmitted to the front surface side of the Si substrate by the same method as in the first embodiment. A Si pattern of holes 8 was formed.

Then, using the etching protection opening pattern 6 as a mask, a SOH solution of 90% at a temperature of 30% is used for S.
The i substrate was etched. Since the SiC film is hardly etched by the KOH aqueous solution, the Si film is formed on the bottom of the transmission hole 8.
A membrane could be formed by leaving only the bonding film of C and Au. After that, the S remaining on the bottom of the transmission hole while performing cleaning
By removing the bonding film of iC and Au, the transmission mask 10 having the structure shown in FIG. 2 was completed.

Thus, the transmission mask of the present invention was completed, but in the case of the first embodiment, ultrasonic vibration may be applied as in the second embodiment. Bonding can be performed at a lower temperature than when ultrasonic vibration is not applied.

The SiC film used in Example 2 is not a metal film, but since it has conductivity, it has a larger thermal conductivity than that of the bonded Au film as compared with the case of using only Si, and is resistant to overheating of the transparent mask. And has an effect similar to the case of joining metals.

[0029]

As described above in detail, according to the transmission mask and the method of manufacturing the same of the present invention, the intermediate layer for bonding the supporting Si substrate and the upper Si substrate and the supporting Si for forming the opening hole are formed. By using a thin film of the same metal thin film or alloy as the etching stop layer of the substrate, the intermediate layer between the supporting Si substrate and the upper Si substrate is not an insulating film as in the past, but a metal thin film or alloy having a large thermal conductivity. Since the thin film is used, it is possible to suppress an excessive temperature rise due to the irradiation of the charged beam and reduce the deterioration of the transfer accuracy due to the thermal deformation of the transmission mask. Further, unlike the conventional case, the step of thermally oxidizing the supporting Si substrate and the step of newly forming a conductive layer for preventing electrification after peeling the mask layer are unnecessary, and the number of steps is reduced and the yield is improved.

[Brief description of drawings]

FIG. 1 is a side view showing a transmission mask according to an embodiment of the present invention.

FIG. 2 is a side view showing a transmission mask according to another embodiment of the present invention.

FIG. 3 is a side view showing a method of manufacturing a transmission mask according to an embodiment of the present invention in the order of steps.

FIG. 4 is a side view showing an example of a method of manufacturing a transmission mask according to another embodiment of the present invention.

FIG. 5 is a side view showing an example of a conventional method of manufacturing a transmission mask in process order.

[Explanation of symbols]

 1, 12 ... Supporting silicon substrate 2, 11 ... Metallic thin film 3, 14 ... Upper silicon substrate 4, 15 ... Bonded silicon substrate 5, 16 ... Mask layer thin film 6, 17 ... Opening pattern 7 ... Resist pattern 8, 18 ... Charge beam transmission hole 9, 19 ... Opening hole 10 ... Transmission mask 13 ... Insulating layer 20 ... Through hole 21 ... Conductive layer

Claims (4)

[Claims] 1. A transmission mask for charged beam exposure, which is produced by using a silicon substrate in which a supporting silicon substrate and an upper silicon substrate are bonded to each other, wherein an intermediate layer for bonding the supporting silicon substrate and the upper silicon substrate is used. A transmission mask for charged beam exposure, wherein at least one kind of metal thin film or thin film made of an alloy is provided on the inner surface of either one or both of the silicon substrates. 2. The thin film of at least one kind of metal thin film or alloy is used as an etching stop layer of a supporting silicon substrate for forming an opening.
The transmission mask for charged-beam exposure according to [4]. 3. A transmission mask for charged beam exposure, which is produced by using a silicon substrate obtained by bonding a supporting silicon substrate and an upper silicon substrate, and an intermediate layer for bonding the supporting silicon substrate and the upper silicon substrate. , A thin film of at least one kind of metal thin film or alloy,
Manufacture of a transmission mask for charged beam exposure, which is formed on one or both inner surfaces of both silicon substrates, and is bonded by solid phase adhesion of the metal thin film or alloy thin film and silicon. Method. 4. A solid phase of metal thin films or alloy thin films or metal thin films and alloy thin films formed on inner surfaces of both silicon substrates facing each other as a method of bonding the supporting silicon substrate and the upper silicon substrate. The method of manufacturing a transmission mask for charged beam exposure according to claim 3, wherein adhesion is used.