JPH06252369A - Glass board for electronic device and its manufacture - Google Patents

Abstract

PURPOSE:To provide a glass board for an electronic device, where a semiconductor single-crystal member is made only in the element formation area on the surface of the glass board, and its manufacture. CONSTITUTION:These are a glass board for an electronic device, where a single- crystal semiconductor member is junctioned only in the element formation area on itself, and the manufacture of the glass board for an electronic device, which forms a cantilever semiconductor 11 is made on the semiconductor substrate, using anisotropic etching, and junctions it on the glass board 20 by anode junction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass substrate for an electronic device having an element formed on a glass plate, and more particularly to a glass substrate for an electronic device used for a liquid crystal display or the like.

[0002]

2. Description of the Related Art In recent years, TFT (Thin Film Transistor:
LCD (Liquid Cystal Dielectric) using thin film transistors
Many electronic devices have been developed in which semiconductor elements such as transistors are directly formed on a glass substrate such as splay (liquid crystal display).

To form a transistor of a conventional TFT LCD, amorphous silicon or polysilicon (polycrystalline silicon) is formed on a glass substrate only at a portion where a transistor is required, and this is manufactured by the same process as a usual LSI manufacturing method. To do.

In such a transistor using amorphous silicon or polysilicon, since the semiconductor member itself on which the transistor is formed is amorphous or polycrystalline silicon, single-crystal silicon used in ordinary LSIs is used. The transistor characteristics are inferior to those of the used transistors.
In order to improve the transistor characteristics, there is a demand for higher on-current (higher mobility), lower off-current, etc. In particular, in LCDs with a built-in driver, the controllability of the threshold and the high speed are improved. Actions are required.

However, as long as amorphous or polycrystalline silicon is used as a semiconductor member on which an element is formed, single crystal silicon is formed on a glass substrate in order to manufacture a transistor with higher performance. Development of glass substrates for electronic devices is required.

[0006]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a glass substrate for an electronic device in which a semiconductor single crystal member is formed only in an element forming region on the surface of a glass plate, and a method for manufacturing the same.

[0007]

The above objects are characterized in that, in a glass substrate on which an element is formed on at least one surface of a glass plate, a single crystal semiconductor member is bonded only to an element forming portion on the glass substrate. This is achieved by a glass substrate for electronic devices.

Further, the above-mentioned objects are to form a first groove on a surface of a (111) single crystal silicon substrate to surround a device forming region except a part thereof, and a single crystal including the first groove. A step of forming a mask material on the surface of the silicon substrate, and a step of removing the mask material formed on the surface of the single crystal silicon substrate surrounded by the first groove and the bottom of the first groove by removing the mask material. Exposing the crystalline silicon surface, forming a second groove in the exposed single-crystal silicon surface of the bottom portion of the first groove, and anisotropically etching the single crystal from the second groove portion. A step of forming a single crystal silicon part in which a portion surrounded by the first groove is cantilevered by etching the inside of the silicon substrate, and the surface of the single crystal silicon substrate and a glass plate are brought into contact with each other for anodic bonding Process and the single crystal Glass for an electronic device, which comprises a step of breaking a part of the substrate left when forming the first groove by peeling off the substrate to leave the single crystal silicon portion on the glass plate. This is achieved by the method of manufacturing the substrate.

[0009]

The glass substrate for an electronic device of the present invention has a single crystal member, for example, single crystal silicon, bonded only to an element forming portion as a semiconductor member on which an element, for example, a transistor formed on the glass substrate is formed. Therefore, it is possible to form an element having characteristics similar to those of a normal LSI element.

In the method for manufacturing a glass substrate for an electronic device of the present invention, first, a step of forming a first groove surrounding a device forming region except a part thereof on a surface of a (111) single crystal silicon substrate, A step of forming a mask material on the surface of the single crystal silicon substrate including the first groove, and a step of forming a mask material on the surface of the single crystal silicon substrate surrounded by the first groove and the bottom portion of the first groove. A step of removing a part of the mask material to expose the single crystal silicon surface; a step of forming a second groove on the exposed single crystal silicon surface of the bottom portion of the first groove; and a step of forming the second groove. A step of forming a single crystal silicon part in which the part surrounded by the first groove is cantilevered by etching the inside of the single crystal silicon substrate from the part by anisotropic etching; Is formed A step of manufacturing a member, and then contacting the glass plate with the surface of the single crystal silicon substrate on which the single crystal silicon portion in which the portion surrounded by the first groove is cantilevered and supported is anodically bonded, Since the single crystal silicon surface of the portion surrounded by the first groove is exposed, as a characteristic of anodic bonding, only the exposed portion of the single crystal silicon is bonded to the glass and covered with another mask material. Do not join the broken parts. Therefore, in the next step, the single crystal silicon substrate is peeled off to rupture a part left when forming the first groove, and the single crystal silicon portion is left on the glass plate by the step of leaving the glass. The single crystal silicon member as a semiconductor member is formed only on a necessary portion on the plate.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings.

1 to 5 show a method of manufacturing a glass substrate for an electronic device according to the present invention in the order of steps.

First, as shown in FIG. 1a, a first groove 2 is patterned on the surface of a (111) single crystal silicon substrate 1 by resist coating and photolithography, and R
It is formed by etching with IE or the like. This first groove 2
In a subsequent step, the element forming region 10 bonded on the glass substrate 20 is surrounded, and the region surrounded by the first groove 2 is not completely surrounded by the first groove 2 and Part of it is patterned during photolithography so as to leave a remaining portion 3 where the first groove 2 is not formed. This remaining portion 3 is for supporting the element forming region 10 in a cantilever manner when the inside of the single crystal silicon substrate 1 is etched in the subsequent steps, and also for joining the glass plate 20 and the element forming region 10 to each other. It is better that the thickness L of the remaining portion 3 is as thin as possible so that the rear single crystal silicon substrate 1 can be easily cut when peeled off.
For example, the thickness is preferably about 5 μm. Further, although the shape of the element formation region is a quadrangle in the illustrated case, it is not particularly limited and may be patterned into a shape necessary for forming an element. FIG. 1b shows a cross-section taken along the alternate long and short dash line AA in FIG. 1a after forming the first groove 2.

The width of the first groove is about 0.1 to 10 μm.
The depth of the first groove 2 determines the thickness of the element forming region 10 as a semiconductor member, and may be appropriately determined according to the application of an electronic device using the glass substrate for an electronic device of the present invention.

Next, as shown in FIG. 1c, a mask material 4 is formed on the surface of the silicon substrate 1 including the first groove 2. As the mask material 4, SiO formed by thermal oxidation or a CVD method is used.
_Two membranes are preferred. This is because the portion where the mask material 4 is present also serves to prevent the bonding with the glass plate 20 during the anodic bonding of the silicon substrate 1 and the glass plate 20 in the subsequent step.

Next, as shown in FIG. 2d, the element forming region 10 and the mask material 4 inside the first groove 2 are removed by resist coating, photolithography and RIE to expose the single crystal silicon surface. Subsequently, RIE is performed to form the second groove 5 on the bottom portion of the first groove 2. At this time, the surface of the element forming region 10 is also etched by RIE, and the thickness of the element forming region 10 as a semiconductor member becomes thin. However, the depth of the first groove 2 can be determined in consideration of the amount in the above step. If it is not a problem.
It should be noted that the depth of the second groove 2 may be that which is necessary for the etching solution to sufficiently circulate when the inside of the single crystal silicon substrate is etched by anisotropic etching in the subsequent steps, for example, about 2 μm. Is preferred.

Next, as shown in FIG. 2e, a KOH aqueous solution in which only the (111) plane is not etched is used as an anisotropic etching solution to form a cavity 6 inside the single crystal silicon substrate 1. As the etching liquid, in addition to the KOH aqueous solution, for example, a hydrazine aqueous solution and an ethylenediaminepyrocatechol solution (11
It is also possible to use an anisotropic etching solution in which only the 1) plane is not etched. As described above, the cavity 6 is for etching the inside of the single crystal silicon substrate 1 with an anisotropic etching solution that does not etch only the (111) plane, and the element forming region 10 without the mask material 4 is formed.
Since the surface is the (111) plane, it is not etched. Then, this etching is performed as shown in FIG.
The etching stops at the plane along the direction (indicated by the dotted line in FIG. 3). The lower portion of the element forming region 10 is surrounded by the grooves 2 and 5, and the etching proceeds inward from the second groove 5. Therefore, the single crystal is completely etched and cantilevered by the remaining portion 3. Silicon part 1
1 is formed.

Next, as shown in FIG. 4, the glass plate 20 is brought into contact with the surface of the single crystal silicon substrate 1 on which the cantilever-supported single crystal silicon portion 11 which is the element forming region 10 is formed by the above-described process. The electrodes 30 and 31 are sandwiched between them, and a high voltage, for example, about 400 to 500 V is applied to perform anodic bonding. At this time, the glass plate 2
0 is bonded only to the element formation region 10 where the silicon surface of the surface of the single crystal silicon substrate 1 that is in contact with the glass plate 20 is exposed, and the portion where the mask material 4 is present on the surface of the single crystal silicon substrate 1 Is the same mask material 4 as glass
Do not join because it is covered by ₂ . Further, the surface of the glass plate 20 and the surface of the element forming region 10 are not in contact with each other even though the thickness of the mask material 4 is slightly (not completely adhered) because the mask material 4 is present on the other surface of the single crystal silicon substrate 1. ) State, there is no problem because a high voltage is applied by anodic bonding and the electrostatic force attracts to the glass surface side where a small gap is generated and a strong electrostatic force is induced to cause bonding.

Finally, the glass plate 20 and the single crystal silicon substrate 1 are peeled off to cut the single crystal silicon portion 11 which is the bonded element forming region 10 from the remaining portion 3 as shown in FIG. It remains on the glass plate 20, and the glass substrate for electronic devices is completed.

The glass substrate for an electronic device of the present invention manufactured as described above can be used, for example, in a TFTLCD, and when used as a TFTLCD,
In order to bond a required number of single crystal silicon parts 11 that are element formation regions on the glass plate 20, in the above-described manufacturing process, a plurality of cantilever-supported single crystal silicon parts 11 are formed. It may be formed on the silicon substrate 1, and the TFT LCD can be manufactured by the same manufacturing process as that in which the TFT is conventionally formed of polysilicon.

Here, as an example, C on a glass plate
An example of forming a MOSTFT will be described.

First, as shown in FIG. 6a, the glass substrate for an electronic device of the present invention is thermally oxidized to form a gate insulating film 41 on the silicon portion 11. Next, as shown in FIG. 6b, n ⁺ polysilicon 42 is formed. Next, FIG. 6c
As shown in, boron ions ( ¹¹ B ⁺ ) are implanted on the entire surface. Next, as shown in FIG. 6d, a portion to be a p-channel TFT is covered with a resist 43 and phosphorus ion ( ³¹ P ⁺ ) is added.
Type in. Then, the interlayer insulating film 44 and the metal wiring 4
5 is performed to complete the TFT.

Since the TFT manufactured in this manner uses single crystal silicon for element formation, it can operate at a higher speed than the conventional TFT manufactured using polysilicon or the like.

The fabrication of the above TFT is an example using the glass substrate for an electronic device of the present invention, and the present invention is not limited to this. For example, a shift register used in an image sensor or the like. It can be used for a three-dimensional device laminated on a glass substrate.

[0025]

As described above, according to the glass substrate for an electronic device and the method for manufacturing the same of the present invention, a single crystal semiconductor such as single crystal silicon is used as a semiconductor member for forming an element on the glass plate. Because it is possible
It is possible to improve the characteristics of the element such as high-speed operation of the element formed on the glass substrate and controllability of the threshold value. Further, the manufacturing method is to form a cantilever-supported semiconductor part by using anisotropic etching used in a usual semiconductor element manufacturing process, and to bond this to a glass plate by anodic bonding. Therefore, a single crystal semiconductor can be easily formed over a glass plate.

[Brief description of drawings]

FIG. 1 is a drawing for explaining a manufacturing process of a glass substrate for an electronic device of the present invention in the order of processes.

FIG. 2 is a diagram for explaining a manufacturing process of the glass substrate for an electronic device of the present invention subsequent to FIG. 1 in order of processes.

FIG. 3 is a diagram for explaining the end point of anisotropic etching.

FIG. 4 is a diagram for explaining anodic bonding.

FIG. 5 is a view showing a state in which a single crystal semiconductor is bonded to a glass plate.

FIG. 6 is a view showing an example of manufacturing a TFT using the glass substrate for an electronic device of the present invention.

[Explanation of symbols]

1 ... Single crystal silicon substrate, 2 ... First
Groove, 3 ... remaining part, 4
... mask material, 5 ... second groove,
6 ... Hollow part, 10 ... Element forming region,
11 ... Single crystal silicon part, 20 ... Glass plate.

Claims (2)

[Claims] 1. A glass substrate for an electronic device, wherein a glass substrate on which an element is formed on at least one surface of a glass plate, a single crystal semiconductor member is bonded only to an element forming portion on the glass substrate. 2. A step of forming a first groove on the surface of a (111) single crystal silicon substrate, which surrounds the element formation region except for a part thereof, and a mask on the surface of the single crystal silicon substrate including the first groove. A step of forming a material, and a part of the mask material formed on the surface of the single crystal silicon substrate surrounded by the first groove and the bottom of the first groove is removed to expose the single crystal silicon surface. And a step of forming a second groove on the exposed single-crystal silicon surface of the bottom portion of the first groove,
Forming a single crystal silicon part in which the portion surrounded by the first groove is cantilevered by etching the inside of the single crystal silicon substrate from the second groove portion by anisotropic etching; A step of contacting the surface of the single crystal silicon substrate with the glass plate for anodic bonding, and tearing off the single crystal silicon substrate to break a part left when forming the first groove, And a step of leaving the single crystal silicon portion left.