JPH09293449A - Cold cathode element and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cold cathode element decreasing a change and deterioration of a characteristic to be capable of acting at a high speed. SOLUTION: On an Si substrate 1 integral with a cold cathode 4, an insulating film 5b, gate electrode film 6b, insulating film 11b1, 11b2 and a focus electrode film 7b are successively layered. In these layered products, an opening part 13 exposing a cold cathode 4 is provided. The insulating film 11b1, 11b2 are provided in a depth from an end part of the gate electrode film 6b. Since a cold cathode element has a structure thus formed, sticking of an electron and a reaction product released from the cold cathode 4 is reduced to the insulating film 11b1, 11b2. Electrostatic capacitance between the gate electrode film 6b and the focus electrode film 7b, determined by the insulating film 11b1, 11b2, is smaller than of the conventional cold cathode element. As a material of the insulating film 11b1, 11b2, for instance, PSG(phosphor silicate glass) is used, by performing etching using hydrofluoric acid, the cold cathode element having this structure is obtained.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a cold cathode device mainly used in vacuum microelectronics. In particular, the present invention relates to a cold cathode device including a so-called gate electrode for performing field electron emission and a so-called focus electrode for providing a focusing property to a trajectory of emitted electrons, and a manufacturing method thereof.

[0002]

2. Description of the Related Art FIG. 31 shows a Si substrate 1 integrated with a cold cathode 4.
The cold cathode 4 is exposed by the opening 23 on the upper surface of the Si
FIG. 3 is a cross-sectional view showing a cold cathode device having a structure in which an O ₂ film 3, a gate electrode supporting insulating film 5b, a gate electrode film 6b, a focus electrode supporting insulating film 110b, and a focus electrode film 7b are sequentially stacked. The gate electrode film 6b and the focus electrode film 7b function as a gate electrode and a focus electrode, respectively. A cold cathode device having a focus electrode generally has a structure shown in FIG.
A conventional method of manufacturing a cold cathode device having a plurality of cold cathodes 4 will be described below.

In FIG. 32, S is attached to the tip of each cold cathode 4.
The iO ₂ mask 2 is placed, and the surface of itself is SiO ₂
Si integrated with a plurality of cold cathodes 4 covered by a film 3
It is a sectional view showing substrate 1. Above the Si substrate 1, a gate electrode supporting insulating film 5, a gate electrode film 6, a focus electrode supporting insulating film 110, and a focus electrode film 7 are sequentially stacked. An opening 23 is provided above each cold cathode 4, and in this opening 23, the gate electrode supporting insulating film 5, the gate electrode film 6, the focus electrode supporting insulating film 110, and the focus electrode are provided. The membrane 7 is discontinuous.

[0004] Cold cathode 4 above the said stack respectively, the gate electrode support insulating film 5a, the gate electrode film 6a, and see focusing electrode support insulating film 110a and the focusing electrode film 7a, the SiO ₂ film 3 Among them, the above-mentioned laminate above the portion other than the periphery of the cold cathode 4 is respectively covered with the gate electrode supporting insulating film 5b, the gate electrode film 6b, the focus electrode supporting insulating film 110b and the focus electrode film 7.
Refer to b.

With respect to the structure shown in FIG. 32, hydrofluoric acid is introduced as an etching solution through the opening 23 which is a discontinuous portion of the laminated structure, so that the SiO ₂ mask 2 and the SiO around the cold cathode 4 are formed. _{2 The} film 3 is removed by etching. At this time, the gate electrode supporting insulating film 5a,
Gate electrode film 6a, focus electrode supporting insulating film 11
0a and the focus electrode film 7a are the SiO ₂ mask 2
It will lose its support base and will be removed at the same time.
This is a so-called lift-off method, and Si
The O ₂ mask 2 is called a spacer.

Since hydrofluoric acid is used as the etching liquid, only SiO ₂ can be selectively etched, and other materials such as SiO are not corroded. Through the above steps, the cold cathode device having the target structure shown in FIG. 33 is obtained.

In the cold cathode device shown in FIG. 31, when the electric field applied between the cold cathode 4 and the gate electrode film 6b serving as the gate electrode exceeds 10 ⁷ V / cm, field electron emission occurs. Occurs. In addition, the focus characteristics of the cold cathode device are improved by controlling the trajectory of electrons emitted by the voltage applied to the focus electrode film 7b which is the focus electrode.

[0008]

FIG. 31 shows electrons e emitted from the cold cathode 4. The arrow shown in the same figure shows how electrons e are emitted. The electrons e are emitted from the tip of the cold cathode 4 at an angle. Focus electrode film 7b and focus electrode supporting insulating film 11
A curved surface connecting the boundary with 0b and the tip of the cold cathode 4 (represented by a line segment in the cross section shown in the same figure).
Here, an acute angle formed with the center line of the cold cathode 4 is an angle α. Electrons e emitted below this curved surface in the figure,
That is, the electrons e emitted at an angle larger than the angle α are
The light is incident on, collides with, and accumulates on the side wall of the focus electrode supporting insulating film 110b. The angle α depends on the tip of the cold cathode 4, the focus electrode film 7b, and the focus electrode supporting insulating film 1.
Since it is determined by the positional relationship with the boundary with 10b,
It depends on the structure of the cold cathode device. Therefore, whether or not the electrons e enter and collide with the focus electrode supporting insulating film 110b depends on the structure of the cold cathode device.

Not only is the emission of electrons from the cold cathode 4 suppressed by the negative electric field formed by the electrons e accumulated on the side wall of the focus electrode supporting insulating film 110b,
The electric field of the focus electrode film 7b is also affected. As a result, the controllability of the focus characteristics of the cold cathode device deteriorates.

Further, the gas remaining in the vacuum and the emitted electrons e collide with each other to decompose the gas, thereby forming ions or radicals of gas molecules. These are combined to form a new product, which is attached to the side wall of the focus electrode supporting insulating film 110b. For example, typically likely to remain in a vacuum, hydrogen (H _2), by a chemical reaction and ionization or radicalization monoxide such as oxygen (CO), for example, as mainly composed of C or C-H An electrically conductive material is formed.

The conductive material causes an electrical short circuit between the focus electrode and the gate electrode,
There is a problem that the cold cathode device cannot operate normally.

The present invention has been made in view of the above points, and the accumulation of electrons on the side wall of the insulating film between the gate electrode and the focus electrode or the side wall of the insulating film of the reaction product generated from the residual gas. It is an object of the present invention to provide a cold cathode device having a structure for preventing fluctuations and deterioration of the characteristics of the cold cathode device due to adhesion to the cold cathode device and a method for manufacturing the same.

[0013]

A cold cathode device according to claim 1, wherein the cold cathode device is sequentially laminated on the substrate while having a substrate, a cold cathode, and an opening for allowing the cold cathode to be exposed.
A first insulating film, a first electrode, a second insulating film, and a second
In the cold cathode device including the electrode, the opening of the second insulating film is wider than the opening of the first electrode.

The cold cathode element according to claim 2 is the cold cathode element according to claim 1.
The cold cathode element according to, wherein the cold cathode is a plurality,
The second insulating film exposes at least two of the cold cathodes through one of the openings of the second insulating film.

According to a third aspect of the present invention, there is provided a method of manufacturing a cold cathode device, comprising: (a) a cold cathode, a first insulating film each having an opening for allowing the cold cathode to be exposed, and a first insulating film laminated in order. The step of preparing a substrate having the first electrode, the second insulating film, and the second electrode; and
And making the opening of the insulating film wider than the opening of the first electrode.

A method of manufacturing a cold cathode device according to a fourth aspect is the method of manufacturing a cold cathode device according to the third aspect, wherein the number of the cold cathodes is plural, and the opening of the second insulating film is provided. There are a plurality of parts, and in the step (b), at least one set of the plurality of openings of the second insulating film is communicated.

A method of manufacturing the cold cathode device according to claim 5 is the method of manufacturing the cold cathode device according to claim 3 or 4, wherein the second insulating film is more preferable than the first insulating film. It is characterized in that it is easily etched in the step (b).

A method for manufacturing a cold cathode device according to claim 6 is the method for manufacturing a cold cathode device according to claim 5, wherein the first insulating film is the cold cathode and the first and the second. It is characterized in that it is more easily etched in the step (b) than the second electrode.

The cold cathode device according to claim 7 is the cold cathode device according to claim 1.
In the cold cathode device as described in 1 above, the opening of the first insulating film is wider than the opening of the first electrode.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1. Hereinafter, Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 4 and 6 to 10,
FIG. 6 is a cross-sectional view showing the method of manufacturing the cold cathode device of the present embodiment in the order of steps. In the present embodiment, the same components as those of the related art are denoted by the same reference numerals.

In FIGS. 1 to 10, two cold cathodes 4 are provided.
Although the manufacturing method of the cold cathode device in which the cold cathodes are simultaneously formed is shown, it can be easily judged that the same manufacturing method can be applied to the case of forming more cold cathodes 4.

FIG. 1 is a sectional view illustrating a Si substrate 1 on which a SiO ₂ mask 2 patterned into a desired shape is placed. The SiO ₂ mask 2 is made of silicon dioxide. As a preparation for forming the SiO ₂ mask 2, first, a silicon dioxide film is formed by thermally oxidizing the Si substrate 1 or by CVD (Chemical Vapor Dep).
osition) method, a vacuum deposition method, a sputtering method, or the like. Next, a SiO ₂ mask 2 is obtained by forming a silicon dioxide film into a desired pattern by the well-known photolithography and etching techniques in the manufacture of semiconductor integrated circuits.

FIG. 2 shows the SiO ₂ mask 2 shown in FIG.
FIG. 3 is a cross-sectional view illustrating a structure obtained by etching the Si substrate 1 using the as a mask. Si substrate 1
Has a conical pyramid 4a having a triangular or trapezoidal cross section.

FIG. 3 shows the structure shown in FIG.
It is sectional drawing which illustrates the structure obtained by performing the thermal oxidation of the Si substrate 1 surface in an oxidizing atmosphere. Si
The cold cathode 4 covered with the O ₂ film 3 is the SiO ₂ mask 2
It exists just below.

Next, in order to obtain the structure shown in FIG. 4, with respect to the structure shown in FIG. 3, a gate electrode supporting insulating film 5, a gate electrode film 6, a focus electrode supporting insulating film 11 and a focus electrode. The film 7 is laminated in order. The gate electrode supporting insulating film 5, the gate electrode film 6, the focus electrode supporting insulating film 11 and the focus electrode film 7 are made of SiO, metal, PSG (Phospho-Silicate Glass) which is a kind of silicate glass and metal. Become.

When stacking, in the vacuum vapor deposition method, the average free path of the vaporized particles to be adhered particles is large, so the vaporized particles go straight. Therefore, by properly setting the conditions, the insulating film 5 for supporting the gate electrode, the film 6 for the gate electrode, and the insulating film 5 for supporting the gate electrode are provided above the boundary between the cold cathode 4 and the silicon substrate 1 where the cold cathode 4 is not formed. The focus electrode supporting insulating film 11 and the focus electrode film 7 are discontinuous as shown in the figure. Due to this discontinuous portion, an opening 13 is formed in each of the cold cathodes 4 in the gate electrode supporting insulating film 5, the gate electrode film 6, the focus electrode supporting insulating film 11 and the focus electrode film 7. There is.

Regarding the gate electrode supporting insulating film 5, the gate electrode film 6, the focus electrode supporting insulating film 11 and the focus electrode film 7, reference numerals are respectively assigned to those laminated above the cold cathode 4. "A" is added to the
The reference numeral "b" is added to each of the O ₂ films 3 stacked above the portion that does not exist around the cold cathode 4. That is, the above-mentioned laminate above the cold cathode 4 has the gate electrode supporting insulating film 5a, the gate electrode film 6a, and the focus electrode supporting insulating film 11a, respectively.
It is also referred to as the focus electrode film 7a. Similarly, the above-mentioned laminates above the portions of the SiO ₂ film 3 that do not exist around the cold cathode 4 are the gate electrode supporting insulating film 5b, the gate electrode film 6b, the focus electrode supporting insulating film 11b and the focus electrode, respectively. It is referred to as the electrode film 7b.

FIG. 5 shows the insulating film 11 for supporting the focus electrode.
It is a perspective view which also illustrates the section in Drawing 4 of b. Although it is separated in FIG. 4 showing the cross section, the focus electrode supporting insulating film 11b is actually integrated. Similarly,
The gate electrode supporting insulating film 5, the gate electrode film 6 and the focus electrode film 7 are also integrated. However, for the sake of simplicity later, particularly with respect to the focus electrode supporting insulating film 11b, the reference numerals described below are used in the cross-sectional view as shown in FIG. 4 or the cross-section shown in FIG.
That is, the focus electrode supporting insulating film 11b which is actually integrated as shown in FIG. 5 is represented as three separated parts in the cross section. Therefore, as shown in FIG. 4, three focus electrode supporting insulating films 11 are formed.
Among b, those existing between the two cold cathodes 4 are referred to as the focus electrode supporting insulating film 11b2, and those not existing between the cold cathodes 4 are referred to as the focus electrode supporting insulating film 11b1.

Then, as shown in FIG. 6, the structure shown in FIG. 4 is covered with a photoresist 8a. At this time, the portion of the focus electrode film 7b that does not have the pattern of the focus electrode is patterned so as not to be covered with the photoresist 8a. Since the photoresist 8a has excellent fluidity during coating, it is possible to satisfactorily cover the discontinuous portion in the opening 13. Etching is performed using the photoresist 8a as a mask to remove the unnecessary portion of the focus electrode film 7b. The structure at the end of the above steps is shown in FIG.

Then, after the photoresist 8a is removed, as shown in FIG. 7, it exists above the portion of the focus electrode supporting insulating film 11b1 which is not the gate electrode pattern of the gate electrode film 6b. The photoresist 8b is formed so that only the portion to be exposed is exposed.
The focus electrode supporting insulating film 11b1 and the gate electrode film 6b are partially and sequentially removed by etching using the photoresist 8b as a mask to form the gate electrode end 9 on the gate electrode film 6b. By this step, the structure shown in FIG. 7 is obtained.

Further, after removing the photoresist 8b, the steps of applying and etching the photoresist 8c are similarly performed. FIG. 8 shows the insulating film 1 for supporting the focus electrode.
1B1 is a cross-sectional view illustrating a structure in which a gate electrode lead-out portion 10 is formed on a gate electrode film 6b by partially removing 1b1. FIG.

By removing the photoresist 8c from the structure of FIG. 8, the structure shown in FIG. 9 is obtained. FIG. 9 shows S provided in the structure shown in FIG.
The focus electrode supporting insulating film 110 made of iO is P
It is sectional drawing which illustrates the structure replaced by the insulating film 11 for focus electrode support which consists of SG. This is the only difference in the structures of the structures shown in FIGS. 9 and 32, respectively, and the other structures are the same. That is, all of the above steps performed to obtain the structure shown in FIG. 9 are the same as the steps for manufacturing a conventional cold cathode device, and only the materials are partly different. This is a feature of the manufacturing method of the cold cathode device.

Of course, the patterning of the focus electrode film 7b, the formation of the gate electrode end 9 and the formation of the gate electrode lead portion 10 are not limited as they are performed in the order described above. Any order may be used as long as these are formed.

Then, as in the case of obtaining the structure shown in FIG. 33, for example, hydrofluoric acid is introduced as an etching solution through the opening 13 which is a discontinuous portion of the laminate. As a result, the SiO ₂ mask 2 and the SiO ₂ film 3 around the cold cathode 4 are removed by etching. At this time, SiO ₂
As the mask 2 is removed, the gate electrode supporting insulating film 5a, the gate electrode film 6a, the focus electrode supporting insulating film 11a, and the focus electrode film 7 are lifted off.
a is removed at the same time.

The rate at which PSG is etched by hydrofluoric acid can be adjusted by the concentration of phosphorus (P) contained, and is characterized by being faster than the rate at which SiO ₂ is etched (edited by the Institute of Electronics and Communication Engineers, "LSI Handbook" pages 263 to 264, 1984, Ohmsha). Therefore, when the SiO ₂ mask 2 is removed and the SiO ₂ film 3 is partially removed, the focus electrode supporting insulating film 11a is removed by lift-off, and the focus electrode supporting insulating films 11b1 and 11b2 are partially removed. Is etched. At this time, the focus electrode supporting insulating film 11b is
The focus electrode supporting insulating films 11b1 and 11b2 each have a trapezoidal structure.

By using hydrofluoric acid as the etching liquid, it becomes possible to avoid erosion of materials other than PSG and SiO ₂ . That is, it is possible to leave the portion of the gate electrode supporting insulating film 5b located below the focus electrode supporting insulating film 11b1. The portion of the gate electrode supporting insulating film 5b located below the focus electrode supporting insulating film 11b1 is necessary for supporting the gate electrode film 6b and the focus electrode film 7b which respectively function as a gate electrode and a focus electrode. Is.

As a result of this step, as shown in FIG. 10, the opening formed by the focus electrode supporting insulating film 11b consisting of the focus electrode supporting insulating film 11b1 and the focus electrode supporting insulating film 11b2 is for the gate electrode. The opening 13 is wider than the opening formed by the film 6b. The structure shown in the figure is a cold cathode device intended in the present embodiment.

Since the cold cathode device of this embodiment has a structure as shown in FIG. 10, in the cross section shown in FIG. 10, the focus electrode supporting insulating films 11b1 and 11b are formed.
Each of the end portions of No. 2 recedes into itself from each end of the gate electrode film 6b. Therefore, the electrons emitted from the cold cathode 4 hardly reach and adhere to the focus electrode supporting insulating film 11b. This will be described below.

FIG. 11 is an enlarged view of the left portion of the cold cathode device shown in FIG. In the same figure, the focus electrode supporting insulating film 110b of the conventional cold cathode device is indicated by a dashed line. The electrons that do not adhere to the focus electrode supporting insulating film 110 of the conventional cold cathode element are emitted from the tip of the cold cathode 4 within the range of the angle α in the same sectional view. However, in the cold cathode device of the present embodiment, since the focus electrode supporting insulating film 11b is recessed from the gate electrode film 6b, the emission of electrons not attached by the angle β shown in the same sectional view. The angle that is played increases. Increasing the angle means that electrons are less likely to be attached.

FIG. 12 shows the tip of the cold cathode 4 and the electrode film 6b.
A curved surface (indicated by a straight line in the same sectional view) connecting the upper end of the focus electrode and the insulating film 1 for supporting the focus electrode.
FIG. 1B is a partially enlarged cross-sectional view illustrating a cold cathode device in contact with 1b (11b1 is shown in the figure). The electrons emitted from the cold cathode 4 cannot reach the shaded portion of the gate electrode film 6b, which is the gate electrode. Therefore, it is preferable to partially remove the focus electrode supporting insulating film 11b by etching so that the focus electrode supporting insulating film 11b is deeper than in the case of the cold cathode device shown in FIG. This makes it possible to reliably prevent the emitted electrons from adhering to the side wall of the focus electrode supporting insulating film 11b.

Further, the angle α + β shown in FIG. 11 is 30.
Even when the focus electrode supporting insulating film 11b is partially removed by etching to the extent that the emitted electrons do not reach within a range of less than 100 degrees, a sufficient effect can be obtained.
This will be described below.

FIG. 13 is a cross-sectional view showing the existence range of electrons emitted from the cold cathode 4, which is obtained from the result of a computer simulation performed assuming that the tip of the cold cathode 4 is spherical. It is a thing. From computer simulation etc., centering on the center of the sphere at the tip,
Electrons are expected to be emitted within an angle range of 30 degrees or less in the cross section. Therefore, if the angle between the end of the focus electrode supporting insulating film 11b and the tip of the cold cathode 4 with respect to the center line of the cold cathode 4, that is, the angle α + β is 30 degrees or less, the effect according to the present embodiment is sufficiently obtained. It is possible to obtain

A similar argument applies to the products resulting from the reaction of electrons with residual gas. That is,
By making the opening formed by the focus electrode supporting insulating film 11b wider than the opening formed by the gate electrode film 6b, accumulation of electrons in the focus electrode supporting insulating film 11b or reaction by residual gas It becomes possible to suppress the adhesion of the product of. As a result, there is an advantage that a cold cathode device with less fluctuation and deterioration of characteristics can be obtained.

An additional advantage of the present invention is that the cold cathode device can operate at high speed.
The capacitance between the gate electrode and the focus electrode is proportional to the product of the dielectric constant and the area of the dielectric material existing between the two electrodes, but the dielectric constant of SiO ₂ , PSG, SiO, etc. is about The value is almost four times. However, by making the focus electrode supporting insulating film 11b made of PSG recede from the gate electrode film 6b, the area occupied by the dielectric part is reduced, so that the capacitance is reduced and the cold cathode device operates at high speed. Is possible.

Although the case where PSG is used as the focus electrode supporting insulating film 11 has been described in the present embodiment, BSG (Boro-Silicate Glass), BP are used.
SG (Boro-Phospho-Silicate Glass), ASG (Arse
Other materials such as no-Silicate Glass) and Si ₃ N ₄ may be used. Further, other materials such as Si ₃ N ₄ and alumina may be used as the gate electrode supporting insulating film 5. That is, if the etching rate of the focus electrode supporting insulating film 11 is sufficiently higher than the etching rate of the gate electrode supporting insulating film 5, the combination of materials of the focus electrode supporting insulating film 11 and the gate electrode supporting insulating film 5 is The material is not limited to the above.

The materials for the gate electrode film 6 and the focus electrode film 7 are Mo, W, Nb and Au, respectively.
Alternatively, it is possible to use various metals such as MoSi ₂ , WSi _{2 and the} like, or compounds and alloys thereof.

Further, in the present embodiment, the focus electrode supporting insulating film 11 is etched simultaneously with the conventional etching of the SiO ₂ mask 2 using hydrofluoric acid for the structure shown in FIG. There is. Therefore, the manufacturing method of the present embodiment can be performed using the conventional manufacturing process, and the cold cathode element of the present embodiment can be easily obtained. However, of course, each etching may be performed individually.

The cold cathode element of the present embodiment can be obtained by making a simple change in the conventional method for manufacturing a cold cathode element by replacing the material of the insulating film. Therefore, it can be said that the method of manufacturing the cold cathode element of the present embodiment is a simple but very effective manufacturing method.

Embodiment 2 A method of manufacturing the cold cathode element according to the present embodiment, which is obtained by improving the method of manufacturing the cold cathode element of the first embodiment, will be described.
14 and 15 respectively, by further performing etching in the manufacturing process of the cold cathode device shown in FIG. 9, the focus electrode supporting insulating film 11b2 is removed from the same sectional view until the focus electrode supporting insulating film 11b is removed.
FIG. 6 is a cross-sectional view and a plan view illustrating a cold cathode device in which b is etched. 14 is a sectional view taken along line XIV-XIV of the cold cathode device shown in FIG.

In FIG. 15, the Si substrate 1, the insulating film 5b for supporting the gate electrode, the film 6b for the gate electrode, the film 7b for the focus electrode, and the cold cathode 4 are shown by solid lines, and the focus is shown. The electrode supporting insulating film 11b is shown by a hidden line. The SiO ₂ film 3 should also be displayed as a hidden line similarly to the focus electrode supporting insulating film 11b, but the illustration is omitted to avoid making the drawing complicated and difficult to see. 16 and 17 are plan views prepared in order to understand the structure of the cold cathode device shown in FIG.

FIG. 16 is a plan view of the structure shown in FIG. 14 with the portion above the gate electrode film 6b omitted. The Si substrate 1 and the cold cathode 4 are exposed through the opening 13 provided in the gate electrode film 6b.

FIG. 17 shows a structure in which the portion above the focus electrode supporting insulating film 11b is omitted from the structure shown in FIG. 14, that is, the focus electrode supporting insulating film 11b is further arranged in the structure shown in FIG. It is a top view which shows the structure. The gate electrode film 6b, the Si substrate 1, and the cold cathode 4 are exposed through the opening 18 of the focus electrode supporting insulating film 11b. The opening 18 is formed by connecting the two openings of the focus electrode supporting insulating film 11b by pushing the etching forward. By further disposing the focus electrode film 7b on this structure, the cold cathode device shown in FIGS. 14 and 15 is obtained.

As shown in FIGS. 14 and 15, the focus electrode supporting insulating film 11b2 does not exist between the cold cathodes 4. However, the focus electrode supporting insulating film 11b1 in FIG. 14 and the focus electrode supporting insulating film 11b in FIG. 15 reliably support the focus electrode film 7b.

Since the openings provided in the focus electrode supporting insulating film 11b are connected by further etching to form the opening 18, the area occupied by the focus electrode supporting insulating film 11b is larger than that in the first embodiment. And even less. Therefore, the cold cathode device having less variation and deterioration in characteristics than the cold cathode device of the first embodiment and capable of operating at higher speed can be obtained by the method for manufacturing the cold cathode device of the present embodiment.

The opening 18 was formed by connecting two openings in the above description.
However, the number is not limited to two, and more openings may be connected.

In this embodiment, the openings 18 that expose the plurality of cold cathodes 4 are formed by connecting the openings provided in the focus electrode supporting insulating film 11b. Then, the focus electrode film 7b is supported by the focus electrode supporting insulating film 11b remaining on the peripheral portion of the cold cathode element. This makes it possible to stabilize the field electron emission characteristics of the cold cathode device while supporting the focus electrode film 7b, and to operate at high speed.

Embodiment 3 For the purpose of obtaining a large operating current, it is customary to use a cold cathode device having a structure in which hundreds to thousands of cold cathodes 4 are integrated. In such a case, as described in the second embodiment, the focus electrode film 7b is supported only by the focus electrode supporting insulating film 11b remaining in the peripheral portion of the opening 13, that is, the peripheral portion of the cold cathode element. It can be difficult to do.

The present embodiment discloses a cold cathode element in which the focus electrode supporting insulating film 11 is left in addition to the focus electrode supporting insulating film 11b.

18 and 19 are a sectional view and a plan view, respectively, illustrating the structure of the cold cathode device provided with the focus electrode supporting insulating film 11c. Embodiments 1 and 2
The illustrated cold cathode device can be obtained by using the same method as the cold cathode device manufacturing method described in (1). The cold cathode device shown in these figures is provided with 40 cold cathodes 4 as an example for the sake of simplicity. FIG. 18 shows the XV of the cold cathode device shown in FIG.
It is a III-XVIII sectional view. In FIG. 19, an enlarged view of a part of the cold cathode device is enlarged. As shown in the enlarged view, each opening 13 exposes each cold cathode 4.

The cold cathode device of the present embodiment will be described. The focus electrode supporting insulating film 11c is arranged at the center of the opening 18 formed by the focus electrode supporting insulating film 11b. In this structure, the focus electrode film 7b is the focus electrode supporting insulating film 1
It is supported by 1b and 11c.

In the cold cathode device of this embodiment, the focus electrode supporting insulating film 11 in the peripheral portion of the cold cathode device is used.
The peripheral portion of the focus electrode film 7b is supported by b. Further, the focus electrode film 7 is formed by the focus electrode supporting insulating film 11c in the central portion of the cold cathode device.
By supporting the central portion of b, the curvature of the focus electrode film 7b is prevented.

In order to obtain the cold cathode device provided with the focus electrode supporting insulating film 11c, the intervals between the cold cathodes 4 may be made different in the method for manufacturing the cold cathode device described in the first and second embodiments. . That is, if the distance between the cold cathodes 4 is different, the width of the focus electrode supporting insulating film 11 between them is naturally different, and the portion where the focus electrode supporting insulating film 11 remains and the remaining portion remain when the etching using hydrofluoric acid is performed. The part that does not do occurs. The remaining portion becomes the focus electrode supporting insulating film 11c.

Of course, the focus electrode supporting insulating film 1
1c does not have to be located in the central portion of the cold cathode device, but may be located between the central portion and the peripheral portion. Further, by providing a plurality of focus electrode supporting insulating films 11c, it is possible to favorably prevent the focus electrode film 7b from being curved.

In the present embodiment, the cold cathode element has a portion where the cold cathode 4 cannot be formed due to the provision of the focus electrode supporting insulating film 11c. However, for example, the number of cold cathodes 4 that are normally integrated is several hundred to several thousand, and the ratio of these to the entire cold cathode 4 is 0.1 to 1% or less. Therefore, the performance of the cold cathode device is hardly affected by providing the insulating film 11c for supporting the focus electrode.

In the present embodiment, it is possible to effectively support the focus electrode of the cold cathode device in which a large number of cold cathodes are integrated, so that a large current operation is possible and fluctuations and deterioration of characteristics are caused. It is possible to obtain a cold cathode device which is small in number and can operate at high speed.

Fourth Embodiment In the present embodiment,
Applying the present invention to a so-called Spindt type cold cathode device (“FED that small-scale production has begun, decision to mass production is imminent”, Nikkei Electronics, P.92, No. 654, 1996.1.29) Will be described. The same components as those in the first to third embodiments are designated by the same reference numerals and the description thereof will be omitted. 20 to 26 are cross-sectional views showing the method of manufacturing the cold cathode device according to the present embodiment in the order of steps.

As shown in FIG. 20, the conductive substrate 12
A gate electrode supporting insulating film 5, a gate electrode film 6, a focus electrode supporting insulating film 11 and a focus electrode film 7 are sequentially laminated on top.

Next, for the structure shown in FIG. 20, the insulating film 5 for supporting the gate electrode, the film 6 for supporting the gate electrode, the insulating film for supporting the focus electrode, which are the portions where the cold cathode is to be formed by using the photolithography technique The film 11 and the focus electrode film 7 are partially removed to form an opening 13. FIG.
FIG. 6 is a sectional view illustrating a structure in which an opening 13 is formed by etching using an etching mask (photoresist) 8d. The opening 13 can be formed by sequentially performing etching using a method such as reactive ion etching that does not cause a large amount of lateral etching. Since the opening 13 is formed, the gate electrode supporting insulating film 5b, the gate electrode film 6b, the focus electrode supporting insulating films 11b1 and 11b2, and the focus electrode film 7 are formed as in the first to third embodiments.
b is obtained.

Next, the spacers 15 required for performing lift-off in a later step are formed by the vacuum evaporation method. FIG. 22 is a cross-sectional view illustrating a structure in which the spacer 15 is formed. At the time of vacuum vapor deposition, the incident angle (measured with reference to the surface) of the vapor deposition particles to the surface of the structure, that is, the focus electrode film 7b is set to an angle close to 0 degree. By setting in this way, the spacer 15
Is formed so as to cover the exposed surface of the focus electrode film 7b.

Next, as shown in FIG. 23, the cold cathode metal 14 is deposited by a vacuum evaporation method. At this time, the vapor deposition particles are set so as to enter in parallel to the extension direction of the opening 13, so that the cold cathode metal 14 is deposited on the bottom surface of the opening 13 and the top surface of the spacer 15. Those deposited on the bottom surface of the opening 13 are referred to as cold cathode metal 14a, and those deposited on the upper surface of the spacer 15 are referred to as cold cathode metal 14b.

The cold cathode metal 14b growing on the spacer 15 also grows laterally at the end of the opening 13. Therefore, as the cold cathode metal 14b grows,
The opening diameter of the cold cathode metal 14b on the opening 13 is gradually reduced. As a result, the cold cathode metal 14a
Are cone-shaped.

When the cold cathode metal 14 is further deposited,
As shown in FIG. 24, the opening of the cold cathode metal 14b is closed at the end. As a result, the cold cathode metal 14a
Becomes a cone. This cold cathode metal 14a is used as a cold cathode of a cold cathode element.

Next, among the structures shown in FIG. 24,
The spacer 15 is removed by etching. With the removal of the spacer 15, the metal 14b for cold cathode loses the supporting substrate, so that it is removed at the same time. That is, the lift-off removes the cold cathode metal 14b. FIG. 25 is a cross-sectional view illustrating a structure in which the spacer 15 and the cold cathode metal 14b are removed. The spacer 15 can be selectively removed by selecting the material of the spacer 15 and the type of etching solution in advance.

As the material of the spacer 15, it is possible to use a metal such as Al or Ni, an inorganic insulating material such as alumina or Si ₃ N ₄ , or an organic insulating material such as photoresist or polyimide. When Al is used as the spacer 15, phosphoric acid or a mixed solution of phosphoric acid and nitric acid may be used as the etching solution. That is, any kind of etching solution may be used as long as it is a combination that selectively removes only the spacer 15.

Then, similarly to the method of manufacturing the cold cathode element of the first embodiment, the focus electrode film 7b is patterned, the gate electrode end is formed, and the gate electrode lead portion is formed (not shown). Next, the focus electrode supporting insulating film 11b is partially removed by, for example, a hydrofluoric acid-based etching solution as shown in FIG. As a result, of the focus electrode supporting insulating film 11b, only the focus electrode supporting insulating film 11b1 remains in the cross section shown in FIG.

In this embodiment, even if the method of forming the cold cathode of the cold cathode element is different, the end portion of the focus electrode supporting insulating film 11b is set back to the inside of the end portion of the gate electrode film 6b. It is shown that it is possible. Therefore, it is possible to obtain a cold cathode element with less variation and deterioration of characteristics regardless of the method of manufacturing the cold cathode element.

Embodiment 5 In the first to fourth embodiments, the focus electrode supporting insulating film 11b is partially removed by using PSG or the like as the material of the focus electrode supporting insulating film 11. In the present embodiment, the gate electrode supporting insulating film 5b is also partially removed to obtain a cold cathode device capable of operating at a higher speed.

FIG. 27 is a cross-sectional view illustrating a structure in which PSG is used as the material of the gate electrode supporting insulating film 5b. The structure shown in the same figure is formed by stacking the gate electrode supporting insulating film 5 using PSG in the step shown in FIG. 4 and performing the same step as that shown in FIGS. Obtainable. That is,
The structure shown in FIG. 9 is the insulating film 5b for supporting the gate electrode.
The different materials are characteristic of the structure shown in FIG.

Then, the structure shown in FIG. 27 is etched with hydrofluoric acid in the same manner as in the step shown in FIG. As a result, the focus electrode supporting insulating film 11b and the cold cathode 4 are formed in the same manner as shown in FIG.
The SiO ₂ film 3 in the peripheral portion is etched, and at the same time, the gate electrode supporting insulating film 5b is also etched. FIG. 28 is a cross-sectional view illustrating a cold cathode device in which the gate electrode supporting insulating film 5b is etched.

In the cold cathode device shown in FIG. 28,
Since the area occupied by the gate electrode supporting insulating film 5b, which is a dielectric, is smaller than that of the cold cathode device shown in FIG. 10, the capacitance of the cold cathode device is reduced. This allows the cold cathode device to operate at high speed.

In the step shown in FIG. 28, further etching is performed, and similarly to the second embodiment, the gate electrode supporting insulating film 5b located below the focus electrode supporting insulating film 11b2 in the cross section shown in FIG. It may be completely removed. Similarly to the case where the focus electrode supporting insulating film 11b1 shown in FIG. 14 supports the focus electrode film 7b, the gate electrode supporting insulating film 5b supports the gate electrode film 6b.

A material that is more easily etched than SiO _{2 and} less easily etched than the focus electrode supporting insulating film 11 may be selected as the gate electrode supporting insulating film 5. That is, the gate electrode supporting insulating film 5b is etched less than the focus electrode supporting insulating film 11b is etched. Figure 30
FIG. 4 is a cross-sectional view illustrating the structure of a cold cathode element in which the amount of the gate electrode supporting insulating film 5b removed by etching is smaller than the amount of the focus electrode supporting insulating film 11b removed by etching.

In the cold cathode device shown in FIG. 30,
Although the insulating film 5b for supporting the gate electrode is removed, it remains sufficiently. Therefore, the gate electrode film 6b and the focus electrode supporting insulating film 11b and the focus electrode film 7b above the gate electrode film 6b are reliably supported.

The etching rate of PSG with hydrofluoric acid depends on the concentration of phosphorus contained. Therefore, even if PSG is used as the material of the insulating film 5 for supporting the gate electrode, the gate electrode supporting film 5 with respect to the etching rate of the insulating film for supporting the focus electrode 11b is changed by changing the concentration of phosphorus.
It is possible to appropriately change the etching rate of b.

[0085]

According to the structure described in claim 1, since the opening of the second insulating film is wider than the opening of the first electrode, the second insulating film is larger than the opening of the first electrode. There is a part where the membrane is deep. This makes it possible to reduce the arrival and adhesion of the electrons emitted from the cold cathode and the products generated by the collision between the residual gas and the electrons, to the second insulating film. This stabilizes the field emission characteristics of the cold cathode.

Furthermore, since the area occupied by the second insulating film is reduced due to the wide opening, the first and second gate electrodes and focus electrodes of the cold cathode device, respectively, are reduced.
The capacitance of the second insulating film sandwiched between the electrodes is reduced. This allows the cold cathode device to operate at high speed.

According to the structure described in claim 2, it is possible to obtain a structure in which the second insulating film does not exist between the cold cathodes. As a result, the cold cathode device has a more stable electron emission characteristic and can operate at a higher speed than the effect of the structure according to the first aspect.

According to the configuration of claim 3, claim 1
It becomes possible to manufacture the cold cathode device described in (1).

According to the structure of claim 4, claim 2
It becomes possible to manufacture the cold cathode device described in (1).

According to the configuration of claim 5, for example,
SiO is used as the first insulating film and PS is used as the second insulating film.
By using a material containing G, BSG, BPSG or Si ₃ N ₄ and etching with hydrofluoric acid in the step (b), the first insulating film can be formed while etching the second insulating film. It is possible to leave it.
As a result, the support base of the first electrode, which is the gate electrode of the cold cathode device, is not lost.

According to the configurations of claims 6 and 7,
While leaving the cold cathode and the first and second electrodes,
Part of the first insulating film can be removed by etching. As a result, in the cold cathode device obtained by the manufacturing method according to claim 6, the capacitance is reduced for the same reason as the effect according to claim 1.
Therefore, the cold cathode device can operate at a higher speed.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a method of manufacturing a cold cathode device according to a first embodiment in the order of steps.

FIG. 2 is a cross-sectional view showing the method of manufacturing the cold cathode device according to the first embodiment in the order of steps.

FIG. 3 is a cross-sectional view showing the method of manufacturing the cold cathode device according to the first embodiment in the order of steps.

FIG. 4 is a cross-sectional view showing the method of manufacturing the cold cathode device according to the first embodiment in the order of steps.

FIG. 5 is a perspective view illustrating a structure of a focus electrode supporting insulating film 11b and a cross section thereof.

FIG. 6 is a cross-sectional view showing the method of manufacturing the cold cathode device according to the first embodiment in the order of steps.

FIG. 7 is a cross-sectional view showing the method of manufacturing the cold cathode device according to the first embodiment in the order of steps.

FIG. 8 is a cross-sectional view showing the method of manufacturing the cold cathode device according to the first embodiment in the order of steps.

FIG. 9 is a cross-sectional view showing the method of manufacturing the cold cathode device according to the first embodiment in the order of steps.

FIG. 10 is a cross-sectional view illustrating the structure of the cold cathode device according to the first embodiment.

FIG. 11 is a cross-sectional view for explaining that it is difficult for electrons to attach to the side wall of the focus electrode supporting insulating film 11b.

FIG. 12 is a cross-sectional view illustrating the structure of a cold cathode device that can effectively prevent attachment of electrons.

FIG. 13 is a cross-sectional view illustrating an angle at which electrons are emitted from the tip of the cold cathode 4.

FIG. 14 is a cross-sectional view illustrating the structure of the cold cathode device according to the second embodiment.

FIG. 15 is a plan view illustrating the structure of the cold cathode device according to the second embodiment.

16 is a plan view illustrating the structure of a gate electrode film 6b of the cold cathode device according to the second embodiment. FIG.

FIG. 17 is a plan view illustrating the structure of a focus electrode supporting insulating film 11b of the cold cathode device according to the second embodiment.

FIG. 18 is a cross-sectional view illustrating the structure of the cold cathode device according to the third embodiment.

FIG. 19 is a plan view illustrating the structure of a cold cathode device according to the third embodiment.

FIG. 20 is a cross-sectional view showing the method of manufacturing the cold cathode device according to the fourth embodiment in the order of steps.

FIG. 21 is a cross-sectional view showing the method of manufacturing the cold cathode device according to the fourth embodiment in the order of steps.

FIG. 22 is a cross-sectional view showing the method of manufacturing the cold cathode device according to the fourth embodiment in the order of steps.

FIG. 23 is a cross-sectional view showing the method of manufacturing the cold cathode device according to the fourth embodiment in the order of steps.

FIG. 24 is a cross-sectional view showing the method of manufacturing the cold cathode device according to the fourth embodiment in the order of steps.

FIG. 25 is a cross-sectional view showing the method of manufacturing the cold cathode device according to the fourth embodiment in the order of steps.

FIG. 26 is a cross-sectional view illustrating a cold cathode device according to the fourth embodiment.

FIG. 27 is a cross-sectional view showing the method of manufacturing the cold cathode device according to the fifth embodiment.

FIG. 28 is a cross-sectional view showing a first example of a cold cathode device according to the fifth embodiment.

FIG. 29 is a cross-sectional view showing a second example of the cold cathode device according to the fifth embodiment.

FIG. 30 is a sectional view showing a third example of the cold cathode device according to the fifth embodiment.

FIG. 31 is a sectional view showing a conventional cold cathode device.

FIG. 32 is a cross-sectional view showing the method of manufacturing the conventional cold cathode device in the order of steps.

FIG. 33 is a cross-sectional view showing the method of manufacturing the conventional cold cathode device in the order of steps.

[Explanation of symbols]

1 Si substrate, 2 SiO ₂ mask, 3 SiO ₂ film, 4
Cold cathode, 5 gate electrode supporting insulating film, 6 gate electrode film, 7 focus electrode film, 8a to 8c photoresist, 8d etching mask (photoresist),
9 gate electrode end, 10 gate electrode lead portion, 11
Focus electrode support insulation film, 12 conductive substrates, 1
3,18,23 Opening, 14 Cold cathode metal, 15
Spacer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazutoshi Morikawa 2-3-3 Marunouchi, Chiyoda-ku, Tokyo Sanryo Electric Co., Ltd. (72) Masatsugu Kawabuchi 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Sanryo Electric Co., Ltd. (72) Inventor Akihiko Hosono 2-3-3 Marunouchi, Chiyoda-ku, Tokyo Sanryo Electric Co., Ltd.

Claims (7)

[Claims] 1. A substrate, a cold cathode, and a first insulating film, a first electrode, and a second electrode, which are sequentially stacked on the substrate, each having an opening for allowing the cold cathode to be exposed. In the cold cathode device including the insulating film and the second electrode, the opening of the second insulating film is wider than the opening of the first electrode. Cold cathode device. 2. The plurality of cold cathodes, wherein the second insulating film exposes at least two cold cathodes by one of the openings of the second insulating film. Cold cathode device. 3. (a) a cold cathode; a first insulating film, which has an opening for allowing the cold cathode to be exposed, and is sequentially stacked; a first electrode; and a second insulating film, A step of preparing a substrate having a second electrode; and (b) making the opening of the second insulating film wider than the opening of the first electrode by etching. And a method for manufacturing a cold cathode device. 4. A plurality of the cold cathodes, a plurality of the openings of the second insulating film, and a plurality of the openings of the second insulating film in the step (b). The method for manufacturing a cold cathode device according to claim 3, wherein at least one set among them is communicated. 5. The method for manufacturing a cold cathode device according to claim 3, wherein the second insulating film is more easily etched in the step (b) than the first insulating film. 6. The step (b) according to claim 1, wherein the first insulating film is formed from the cold cathode and the first and second electrodes.
6. It is easily etched in the process of claim 5.
A method for manufacturing a cold cathode device according to item 1. 7. The cold cathode device according to claim 1, wherein the opening of the first insulating film is wider than the opening of the first electrode.