KR0176324B1 - Method for controlling distance between emitter and anode of diode type field emission device - Google Patents

Abstract

The present invention relates to a method of controlling the distance between the field emission portion and the anode of the diode-type field emission device, and the distance between the end of the field emission portion and the surface of the anode by a method of forming an insulating thin film and a groove between the cathode substrate and the anode substrate. It can control the field distribution from the field emitter accurately by controlling the resolution of several tens of micrometers from below 1㎛ to hundreds of micrometers, and can effectively control the field emission voltage and emission current. It is possible to implement a highly reliable diode type field emission device that can be applied not only to display devices but also to manufacturing tunneling parsers using micro tips.

Description

Distance control method between field emission part and anode of diode type field emission device

1a and 1b show the cross-sectional structure of a diode-type field emission device,

1A is a sectional view showing a case where a tip is used as the field emission unit.

1B is a sectional view showing a case where a film is used as the field emission unit.

2a to 2e are the first embodiment of the present invention, a process flow diagram showing a method for manufacturing a diode-type field emission device that proposes a method for controlling the distance between the field emission portion and the anode using an insulating thin film.

3A to 3H illustrate a method of manufacturing a diode-type field emission device that provides a method of controlling a distance between a field emission part and an anode using a groove and an insulating thin film formed in a cathode substrate as a second embodiment of the present invention. One process purity.

4 is a cross-sectional view illustrating a structure of a field emission device in which a distance between the field emission unit and the anode is adjusted using a groove formed in the cathode substrate, an insulating thin film, and a groove formed in the anode substrate as a third embodiment of the present invention.

5a to 5g are a fourth embodiment of the present invention, the diode-type field emission device of the method for controlling the distance between the field emission portion and the anode using a selective oxide film growth technology using the insulating thin film and the locus process Process purity diagram showing the manufacturing method.

6A to 6G are the fifth embodiment of the present invention and show a process flow diagram showing a method of manufacturing a diode-type field emission device used as a display element.

* Explanation of symbols for main parts of the drawings

10: silicon substrate 12,12 '': insulating thin film

12 ', 12' '': insulating thin film pattern 13: silicon nitride film

14 silicon tip 16 anode substrate

16: anode substrate 18 silicon groove

20: thermal oxide film 22: square window

24 ': transparent conductive film 26: light emitting layer

The present invention relates to a method for manufacturing a field emission device, and more particularly, in a diode-type field emission device, the distance between the end of the field emission portion and the surface of the anode at a resolution of several tens of micrometers ranging from 1 μm or less to several hundred μm. The present invention relates to a method of controlling the distance between a field emission part and an anode of a diode type field emission device that is adjustable.

The structure of the field emission device disclosed in Patent Application No. 95-12870 is largely as shown in FIGS. 1A and 1B when the device manufacturing is completed using the field emission tip as the cathode, and the field emission membrane is used as the cathode. It is divided into the case where the device manufacture is completed by using.

In the case where the tip is used as the field emission portion as shown in FIG. 1A, a substrate (mainly a semiconductor substrate including silicon), which acts as a cathode having a groove having a predetermined thickness, and a bottom portion of the groove of the substrate Needle-shaped field emission portions formed in, for example, a semiconductor tip (2) made of metal or silicon, an insulating thin film (3) electrically insulating the cathode and the anode, and a field emission tip (2) It can be seen from the anode substrate 4 (which may be a semiconductor substrate including silicon or a glass substrate coated with a transparent coating film, etc.) disposed at regular intervals d (distance).

On the other hand, when the membrane is used as the field emission portion as shown in FIG. 1B, a functional film capable of emitting electrons even at a low voltage is applied as the field emission membrane 5 instead of the interleaver field emission tip 2. It can be seen that the same structure as in Figure 1a.

In both of these diode-type field emission devices, d representing the distance between the field emission portion (field emission tip 2 or field emission film 5) and the anode is a voltage applied for electron field emission. However, it is a very important factor in determining the magnitude of the current flowing from the cathode to the anode by the emitted electrons.

Therefore, it is necessary to precisely control the field emission device having excellent characteristics, but until now, there is no known technique devised to control the distance d between the field emission unit and the anode. to be.

Accordingly, the present invention has been made in view of the above, and the distance d between the field emission portion and the anode in the diode type field emission device disclosed in Patent Application No. 95-12870 is lower than 1 µm to several hundred µm. An object of the present invention is to provide a distance control method between a field emission part and an anode of a diode-type spreading-emitting device that can be adjusted with a resolution of several tens of microseconds.

According to a first aspect of the present invention, there is provided a method of controlling a distance between a field emission part and an anode of a diode type field emission device, the method including: forming an insulating thin film having a predetermined thickness on a semiconductor substrate; Forming a mask pattern by selectively etching the insulating thin film in a portion where the field emission unit is formed; Forming a plurality of tips under the mask pattern by wet or dry etching the mask pattern with a cutting mask; Removing the mask pattern on the tip; And bonding the anode substrate to the insulating thin film formed on both edge portions of the semiconductor substrate.

In order to achieve the above object, the method of controlling distance between the field emission part and the anode of the diode-type field emission device according to the second and fifth embodiments of the present invention selects and etches a semiconductor substrate to form a groove having a predetermined thickness. Forming step; Forming a mask pattern by selectively etching the insulating thin film inside the groove; Forming a plurality of tips under the mask pattern by performing wet or dry etching on the mask pattern with an etching mask; Removing the insulating thin film pattern on the tip; And bonding the anode substrate to the insulating thin film formed on both edge portions of the semiconductor substrate.

According to a fourth embodiment of the present invention, there is provided a method of controlling a distance between a deployment emission part and an anode of a diode-type field emission device according to a fourth embodiment of the present invention, by using a first insulating thin film and a second insulating thin film having a predetermined thickness on a semiconductor substrate. Depositing sequentially; Forming a mask pattern by selectively etching the first and second insulating thin films on the portion where the field emission unit is to be formed; Forming a plurality of tips under the etching process using the mask pattern as a mask; Thermally oxidizing to grow an oxide film in a portion where a mask pattern is not formed; Removing the mask pattern and the oxide film; Removing the second insulating thin film; And bonding the anode substrate to the first insulating thin film formed on both edge portions of the semiconductor substrate.

As a result of the above process, the distance between the field emitter and the anode can be precisely adjusted.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

The present invention is directed to more precisely control the distance between the field emission portion and the anode of the diode-type field emission device in order to implement a field emission device of excellent characteristics, in Figures 2a to 4 Two types of methods are suggested, depending on the range and resolution desired.

First, as a first embodiment, a method of controlling a distance between a field emission part and an anode using an insulating thin film will be described with reference to the process steps shown in FIGS. 2A to 2E.

First, as shown in FIG. 2A, an insulating thin film 12 including a thermal oxide film is formed on the silicon substrate 10 to have a thickness corresponding to a desired d value, and as shown in FIG. 2B, the insulating thin film (12) is patterned to have other suitable shapes, including circular, to form an insulating thin film pattern 12 '.

Thereafter, wet or dry silicon etching is performed using the insulating thin film pattern 12 ′ as an etching mask. As a result, etching in the lateral direction is performed to form a plurality of silicon tips 14 as shown in FIG. 2C.

At this time, when the complete tip is formed, the mask insulating thin film pattern 12 ′ on the tip 14 is automatically removed as shown in FIG. 2d, and only the surrounding insulating thin film pattern 12 remains.

Next, the diode-type field emission device having a d corresponding to the thickness of the insulating thin film is completed by performing the cleaning process and then bonding it to the anode substrate 16.

In this case, the process of bonding the insulating thin film pattern 12 to a silicon or glass substrate or the like is carried out in the Silicon-to-silicon direct bonding method, Journal of Applied Physics, vol. 60, no. 8, pp.2987-2989, and DI. Pomerantz, Anodic bonding, US Patent No. Preference is given to using direct or anodic bonding, in which no bonding medium has already been known in 3,397,278.

The insulating thin films 12 and 12 'used as an etching mask may be formed using a silicon nitride film or an oxide film by chemical vapor deposition (CVD) instead of the thermal oxide film, wherein the thickness range of d may be Given the range of possible formation, it can range from tens of microns to several microns. In addition, the controllability (resolution: resolution) can be adjusted to a range of several tens of microseconds, considering the magnetic flux or deposition rate of the thin film.

As the material of the anode substrate 16, a semiconductor material including a silicon substrate is used for a simple vacuum diode, and a glass material in which a light emitting layer and a transparent conductive thin film are formed is used for a display element.

On the other hand, as a step of slightly modifying the process, before bonding the positive electrode substrate 16 to the insulating thin film pattern 12 ', an insulating thin film pattern is also formed on the surface of the positive electrode substrate 16 and then bonded by d. You can also double the adjustable range.

The series of methods based on FIG. 2 corresponds to a case where d is mainly within several micrometers, and in the case of adjusting d in a wider range, a second embodiment is illustrated in FIGS. 3a to 3h. A field emission device is manufactured according to the process purity.

3 shows a method of controlling the distance between the field emitter and the anode using the etched groove and the insulating thin film, and the adjusting method is as follows.

First, as shown in FIG. 3A, the insulating thin film 12 is grown on the silicon substrate 10, and then selectively etched to form an insulating thin film pattern 12 'of the type shown in FIG. 3B.

Next, as illustrated in FIG. 3C, wet or dry silicon etching is performed using the insulating thin film pattern 12 ′ as an etch mask to form a silicon groove 18 having a depth of d1.

Subsequently, the insulating thin film pattern 12 ′ is removed and an insulating thin film 12, such as a thermal oxide film, is formed on the entire surface of the silicon substrate having a d2 thickness. The process proceeds similarly to the process shown in FIGS. 2A-2E.

That is, the insulating thin film 12 formed in the groove 18 is selectively etched to have the shape shown in FIG. 3e to form an insulating thin film pattern 12 ′ ″, which is wet or dry silicon etched using an etching mask. Is performed to etch in the lateral direction to form the silicon tips 14 of the type shown in FIG. 3f.

At this time, when the complete tip is formed, as shown in FIG. 3G, the mask on the tip 14 is automatically removed and only the surrounding insulating thin film pattern 12 '' 'remains.

Next, after the cleaning process is bonded to the positive electrode substrate 16, as shown in FIG. 3h, the distance d1 corresponding to the depth of the groove 18 and d2 corresponding to the thickness of the thermal oxide film, that is, d A diode type field emission device having a distance dd + d2 as a distance between the field emission unit and the anode is completed.

In this case, the upper limit of d may be extremely close to the thickness of the silicon substrate 10. For example, when a silicon substrate having a thickness of 500 µm and a diameter of 4 inches is used as a cathode substrate, the depth of the groove can be adjusted to around 500 µm, so that the upper limit of d approaches 500 µm.

Further points to be described in the above process based on FIG. 3 are as follows. First, the wet and dry etching methods can be used to form the grooves, but wet etching, which has relatively good etching surface properties, is more preferable, and in this case, the etching rate can be easily adjusted, and the etching surface properties are good. It is preferable to proceed with the process using the F-etch solution, which is a crystal-dependent etching solution that can control the etching of.

At this time, the etching rate of the (100) silicon crystal plane of the F-etch solution can be adjusted to about 0.8-1.4㎛ / min depending on the composition and the use temperature, so the depth of the groove to be etched is also less than 1㎛ It can be regarded as adjustable with.

Next, the present invention relates to a process of selectively etching the insulating thin film 12 formed in the groove, and in order to proceed with the etching process, a photolithography method, which is commonly used, may be used. Special patterning processes, such as patterning (electrol-beam direct lithography), may be applied.

Also in accordance with FIG. 3, insulating thin films such as thermal oxide films, silicon nitride films, and chemical vapor deposition methods can be used. In addition, in the case of anode materials, semiconductors including silicon substrates can be used as simple vacuum diodes. When the material is used as a display element, a glass material in which a light emitting layer and a transparent conductive film are formed may be used. In the latter case (used as a display element), it is explained in detail in the process of FIG. 6 mentioned later.

Meanwhile, FIG. 4 shows a cross-sectional structure of the field emission device formed through the process of controlling the distance between the field emission unit and the anode using the groove formed in the cathode substrate, the insulating thin film, and the groove formed in the anode substrate. Is shown.

The manufacturing method of the field emission device proceeds in the same manner as shown in FIGS. 3A to 3G, but before bonding the anode substrate 16 and the insulating thin film pattern 12 ′ '' in the third step, the first method is performed. After the groove 18 'is formed on the anode substrate using an etching mask, the groove 18' is formed by bonding the groove 18 'to the cathode substrate 10 on which the insulating thin film pattern 12' '' is formed, as shown in FIG. 3g. do.

As described above, in the case of using the silicon substrate having the grooves 18 'formed as the anode substrate 16, the value of d can be adjusted more optically.

In this case, the distance d between the field emitter and the anode is defined as d = d1 + d2 + d3 corresponding to the sum of the depths d1 and d3 of the grooves formed in each substrate and the thickness d2 of the insulating film.

Next, the distance between the field emitter and the anode of the diode-type field emission device is described with reference to the process steps shown in FIGS. The following shows how to adjust.

5A to 5G show an application example of the first embodiment, and FIGS. 6A to 6G show an application example of the second embodiment.

First, the process shown in FIGS. 5A to 5G is described as the fourth embodiment. This process has the advantage that it is possible to adjust the value of d more accurately than the first embodiment mentioned above.

First, as shown in FIG. 5A, the insulating thin film 12 is grown on the single crystal silicon substrate 10. For example, a thermal oxide film is grown to a thickness within 0.1-3 mu m, and a thickness within the range of 500-3000 kPa on the thermal oxide film. The silicon nitride film 13 having it is deposited. Here, the case where the thickness of the insulating thin film 12 is grown to a thickness of 1 μm and the thickness of the silicon nitride film 13 is deposited to a thickness of 2000 kPa will be described.

Then, the thermal oxide film and the silicon cut film 13 are selectively etched using a photolithography process to form an etching mask (a) having a diameter of 2 μm, which is thermally oxidized and a silicon nitride film as shown in FIG. 5B. .

The specimen prepared as described above is placed in a solution consisting of nitric acid-acetic acid-fluoric acid (hereinafter referred to as NAF) and etched for 1-3 minutes. As shown in FIG. Silicon tips 14 having a diameter of 1 μm are formed under the real mask a.

Thereafter, when the specimen prepared as a result of the process is put into a wet oxygen atmosphere and thermally oxidized, only the portions not covered by the etching mask (a) are selectively oxidized, so that the partial thermal oxide film 20 is shown in FIG. Is formed. The process of selectively growing the thermal oxide film by the nitride film mask is called a local oxidation of silicon (LOCOS) process.

As described above, when the specimen in which the locus process is completed is placed in a buffered oxide etchant (BOE) solution or the thermal oxide film 20 is removed by dry etching, the thermal oxide film is removed and finished as shown in FIG. A plurality of very sharp silicon tips 14 are formed. At this time, the etching mask (a) on the silicon tip 14 is also removed.

Thereafter, as shown in FIG. 5F, the silicon nitride film 13 is removed by wet or dry etching, and the anode substrate 16 is placed on the thermal oxide film, which is the insulating thin film 12 ', by anode bonding or direct bonding. By joining, this process is completed. As a result, the distance d between the tip and the anode is adjusted to 1 mu m, which corresponds to the thickness of the thermal oxide film.

Next, as a fifth embodiment, the processes shown in Figs. 6A to 6G will be described. The diode-type field emission device proposed in the above process is made to be suitable for a display device, and the substantial progress of the process is similar to that of the second embodiment.

That is, as shown in FIG. 6A, first, an insulating thin film 12 ', for example, a thermal oxide film within 500-3000 thick chestnut, is grown on a single crystal silicon substrate 10, and then selectively etched through a photolithography process to 1 *. A square window 22 having a size of 1 mm 2 is formed. Here, the case where the insulating thin film 12 'is deposited to a thickness of 1000 mW will be described.

Then, as shown in FIG. 6B, the prepared specimen was placed in an 'F-etch' solution at 115 ° C. and etched for 3 minutes to form a square groove 18 having a size of 1 * 1 mm 2 and a depth of 4 μm. And the insulating thin film 12 'is removed using a BOE solution.

Subsequently, as shown in FIG. 6C, an insulating thin film 12, for example, a CVD oxide film, is deposited on the silicon substrate 10 including the grooves 18 to a thickness of 0.1-3 mu m. Here, the case where the CVD oxide film is deposited with a thickness of 1 탆 will be described.

Then, as shown in FIG. 6D, a photolithography process is performed on the oxide film deposited in the square groove 18 to form a circular insulating thin film pattern 12 '' 'having a diameter of 2 占 퐉, and is prepared as described above. Place the specimen in NAF solution and perform silicon etching for 4 minutes.

As a result, a plurality of silicon tips 14 having a height of 1 μm are formed by etching in the lateral direction using the insulating thin film pattern 12 ′ ″, followed by the insulating thin film on the tip 14. By removing the pattern 12 '' ', a pattern as shown in Fig. 6E is formed.

Thereafter, as illustrated in FIG. 6F, the anode glass substrate 16 having the transparent mucosa 24 and the light emitting layer 26 is manufactured to be applied to the field emission display device.

Next, two types of substrates prepared as shown in FIG. 6G, that is, the cathode silicon substrate 10 and the anode glass substrate 16 are bonded to each other by anodic bonding or direct bonding, thereby forming a vacuum diode type field emission display device. Complete the manufacture.

At this time, the distance d between the end of the field emission portion of the silicon tip 14 and the surface of the transparent conductive film 24 formed on the anode substrate 16 has a groove depth d1 = 4 mu m and an insulating thin film CVD. It can be precisely defined as 5 mu m, which is a sum of the thickness d2 = 1 mu m of the oxide film.

As described above, according to the present invention, the distance between the end of the field emission portion and the surface of the anode can be adjusted to a resolution of several tens of micrometers from 1 μm or less to several hundred μm, so that the electric field distribution from the field emission portion can be accurately measured. In addition, it is possible to effectively control the field emission voltage and emission current, as well as to implement a highly reliable diode-type field emission device that can be applied to the field emission display device as well as to manufacture a tunneling sensor using a micro tip.

Claims (23)

Forming an insulating thin film having a predetermined thickness on the semiconductor substrate; Forming a mask pattern by selectively etching the insulating thin film in a portion where the field emission unit is to be formed; Wet or dry etching the mask pattern with an etch mask to form a plurality of tips under the mask pattern; Removing the mask pattern on the tip; And a step of bonding the anode substrate to the insulating thin film formed on both edge portions of the semiconductor substrate, wherein the distance between the field emission portion and the anode of the diode-type field emission device is formed. The method of claim 1, further comprising, after the process of removing the mask pattern on the tip, forming an insulating thin film having a predetermined thickness on the inner edge portion of the anode substrate at a position contacting the insulating thin films formed on both edge portions of the semiconductor substrate. Method for controlling the distance between the field emission portion and the anode of the diode-type field emission device, characterized in that formed. The method of claim 1 or 2, wherein the insulating thin film is formed of any one selected from a thermal oxide film, a silicon nitride film, and a CVD oxide film. The method of claim 1, wherein the diode-type field emission device, when used as a display device, after the process of removing the mask pattern, forming a transparent conductive film on the glass substrate; And forming a light emitting layer on the transparent conductive film, and manufacturing a positive electrode substrate. The method of controlling a distance between a field emission part and an anode of a diode-type field emission device is further included. The method according to claim 1 or 2, wherein the insulating thin film is formed in a thickness range of several tens of micrometers to within several micrometers. Sequentially depositing a first insulating thin film and a second insulating thin film having a predetermined thickness on the semiconductor substrate; Forming a mask pattern by selectively etching the first and second insulating thin films on the portion where the field emission unit is to be formed; Forming a plurality of tips under the etching process using the mask pattern as a mask; Thermally oxidizing to grow an oxide film in a portion where a mask pattern is not formed; Removing the mask pattern and the oxide film; Removing the second insulating thin film; And a step of bonding the anode substrate to the first insulating thin film formed on both edge portions of the semiconductor substrate, wherein the distance between the field emission portion and the anode of the diode-type field emission device is formed. The method of claim 6, wherein the first insulating thin film and the second insulating thin film are formed of a thermal oxide film and a silicon nitride film. The method of claim 6, wherein the first insulating thin film is formed to a thickness of 0.1-3 μm. 7. The method of claim 6, wherein the second insulating thin film is formed to a thickness of 500 to 3000 mW. The field emission part and the anode of the diode-type field emission device according to claim 6, wherein the plurality of tips are formed by immersing a specimen having a mask pattern in an etchant consisting of nitric acid-acetic acid-fluoric acid for 1-3 minutes. How to adjust the distance. 7. The method of claim 6, wherein the mask pattern and the oxide film are removed in a BOE solution or removed by dry etching. Selectively etching the semiconductor substrate to form a groove having a predetermined thickness; Forming an insulating thin film having a predetermined thickness on the entire surface of the substrate including the groove; Forming a mask pattern by selectively etching the insulating thin film inside the groove; Forming a plurality of tips under the mask pattern by performing wet or dry etching on the mask pattern with an etching mask; Removing the mask pattern on the tip; And a step of bonding the anode substrate to the insulating thin film formed on both edge portions of the semiconductor substrate, wherein the distance between the field emission portion and the anode of the diode-type field emission device is formed. The method of claim 12, wherein the forming of the groove having a predetermined thickness in the semiconductor substrate comprises: forming an insulating thin film on the semiconductor substrate; Selectively etching the insulating thin film to form a mask pattern; Forming a groove by wet or dry etching the mask pattern using an etching mask; And a step of removing the mask pattern, wherein the distance between the field emission unit and the anode of the diode-type field emission device is formed. The method of claim 12, further comprising forming a groove having a predetermined thickness by selectively etching the anode substrate after the process of removing the mask pattern on the tip. A method of controlling the distance between the field emitter and the anode. The method of claim 12 or 13, wherein the groove is formed by a wet etching process using an 'F-etch' solution. The method of claim 12, wherein the mask pattern formed in the groove is formed by using a photolithography process or an electron beam etching process using a photosensitive film pattern as a mask, the distance between the field emission portion and the anode of the diode-type field emission device, characterized in that Way. The method of claim 12, wherein the insulating thin film is formed of any one selected from a thermal oxide film, a silicon nitride film, and a CVD oxide film. The method of claim 12, wherein the diode-type field emission device is a display device, comprising: forming a transparent conductive film on a glass substrate after a process of removing a mask pattern on the tip; And forming a light emitting layer on the transparent conductive film, and manufacturing a positive electrode substrate. The method of claim 13, wherein the mask pattern is removed by a BOE solution. The method of claim 12, wherein the insulating thin film is formed to a thickness of 0.1-3 μm. 15. The method of claim 13, wherein the insulating thin film is formed of a thermal oxide film. 15. The method of claim 13, wherein the insulating thin film is formed to a thickness of 500 to 3000 mW. The method of claim 12, wherein the plurality of tips are formed by etching the prepared specimen in a solution consisting of nitric acid-acetic acid-fluoric acid for 3-5 minutes between the field emission portion and the anode of the diode-type field emission device How to adjust the distance.