JPS60246686A - Thin-film nonlinear resistance element - Google Patents

Abstract

PURPOSE:To reduce the frequency of generation of defective dielectric breakdown voltage, and to strengthen and stabilize the titled resistance element mechanically by making the film thickness of an insulating film formed at the stepped section of a pattern for a lower metal thicker than that of an insulating film shaped to the surface of the pattern for the lower metal. CONSTITUTION:A lower metal 2 is formed onto an insulating substrate 1. A metal, whih can be anodized, such as tantalum, aluminum, etc. is selected as the material of the lower metal. A surface section insulating film 4 is shaped onto the surface of the metal 2. The unnecessary sections of the surface section insulating film 4 and the lower metal 2 are removed through a photoetching method. When the lower metal is anodized under the state, only the stepped section of a pattern for the lower metal 2 is anodized, and a stepped-section insulating film 3 is formed. The stepped-section insulating film 3 is shaped, a resist is peeled, and lastly the upper metal 5 is formed and patterned, thus completing an MIM element having structure in this invention.

Description

[Detailed description of the invention] [Untechnical! ! [Ir] The present invention is based on Ki A momme, ~ (Ha leg 1 which is made 1"1 by forming a three-layer double membrane 4'iIi structure of lower gold area, Zetsukou 9, and lower gold 136 on the board. This relates to a linear resistance element (hereinafter referred to as "MIM element") K.

[Conventional wave nail]

The M-engine M-element is characterized by its non-1st form and
At present, the switching element used for the display (ilr) has been retired, and its tail and other parts for the liquid crystal display are no longer used.

ing. (JJ, ha, B(LrOff, el (Lt
, 3ID '3Q IJIOEST, P. 200.1
980) L, conventional M I M, A child may cause fluctuations in the rupture of the occlusion & 1 《f pressure, and a certain level of 《edge fracture》. , even with IU specifications 2i, a significant percentage of manufactured MIM devices fail at applied frost and pressures lower than their specifications. There was a problem that it caused This problem becomes particularly serious when a large number of M elements are formed on an insulating base and all M elements need to operate normally. For example, if we consider the case where an M element is applied to a single liquid crystal display, the number of display pixels of the liquid crystal display in this case is generally from several tens to tens of thousands, and each pixel has an open base - number of pixels. Since the MIM element is very thick, in order to obtain a perfect display, it is necessary for all of the tens to tens of thousands of M elements formed on the substrate to operate normally. I can understand how important the issue is. The following is an outline and summary of the dielectric breakdown tests conducted on conventional MIM elements by motorists, keeping in mind that the M element is used in the liquid crystal display VC H5. The M element used in the test used tantalum as the base metal, tantalum pentoxide obtained by anodic oxidation as the insulating film, and chromium as the earth metal! I! 8
+Created. Also, each sink/rib crotch IF? - is 1g of lower gold;
The tantalum is about 2000Å, and the chromium on the bottom gold is about 1
It is 2ooX.

The thickness of tantalum pentoxide is 500A to 600A, since the nonlinear resistance characteristics of the MIM element depend in principle on the thickness of the red film. , is inevitably determined from the conditions of type 1 resistance characteristics.

On the other hand, from the driving conditions of the liquid crystal, it is determined that the absolute pressure and major destruction '1 of the MIM element are 1()1 or more at a DC 1h pressure.

For approximately 500 MIM element samples, the breakdown voltage caused by applying DC 11 (pressure) was calculated using pi4, and M
For about 95% of the IM element samples, dielectric breakdown ↑ (1 Sho) was concentrated in the 'aj8E range of 17 to +9 V, but M I M elements with dielectric breakdown 1L voltage less than 10 V, i.e. It was shown that about 0.5% of the total M I M elements do not satisfy the minimum dielectric breakdown voltage condition required from the drive conditions of the above. One of the causes of insulation breakdown voltage defects is thought to be that the electric field in the insulating film of the M element becomes non-uniform when pressure is applied, causing concentration of the electric field. In the conventional MIM device, the shape of the stepped portion of the bottom metal pattern formed by etching is not as smooth as the pattern surface, and furthermore, the thickness of the insulating film formed on the bottom metal surface is Since the pattern step part and the pattern surface part of the lower gold knitting are the same, it is unrelated.
The concentration of electric field due to K is 1 of the pattern step t, +b for the bottom metal.
ff3 j3, ru is more likely to occur than tearing of the pattern surface portion for the bottom metal. As described above, the conventional M-engine M-element has a defect in its structure in that it is prone to rupture and pressure failure.

〔the purpose〕

An object of the present invention is to eliminate such defects and reduce the frequency of occurrence of dielectric breakdown IL pressure defects in MIM elements. Yet another object of the present invention is to provide a mechanically strong and stable Ivl engineering element.

〔overview〕

In the structure of the M element of the M process, the present invention is characterized in that the insulation film formed on the step part of the pattern of the lower metal part of the MIM thread is formed on the pattern surface of the lower metal part 1. Absolutely ← Jllo of Membrane ``It is a sign of benefit to be 1 degree worse than I.

〔Example〕

Hereinafter, the present invention will be explained in 1. using FIG. ) 1 will be explained.

FIG. 1 shows a cross-sectional structure of an M element according to an embodiment of the present invention. Lower gold plate 21 step insulation part! 31 Surface section χ crotch 4. and earth metal 5 to 6:4. Compared to the conventional MIM device, the flaw characteristics of the MIM device shown by FIG.
The step IP section insulator 3 is thicker than the surface section insulating film 4. In this structure, the step insulating film 3 is thicker than the conventional one, so the (a field) inside the step insulating film 3 due to the voltage applied to the MIM element is false compared to the conventional one. 1. The electric field defects due to the uneven shape of the pattern step part of the lower gold box obtained by etching are reduced due to the uneven shape of the step part assembly film 3.For the above reasons, The frequency of occurrence of low-voltage dielectric breakdown in the step insulating film is significantly reduced.In the structure of the MIM element according to the present invention, since the step insulating film is thick, the M4. Therefore, the stepped portion does not function as a nonlinear resistance element.The effective MIM portion that gives nonlinear resistance characteristics to the MIM element is the portion excluding the stepped portion from the entire three-layer structure of the bottom metal, insulating film, and soil metal. Next, we will describe the manufacturing process for obtaining the drawing of the M element in the present invention. Figure 2 shows the first embodiment of the manufacturing process for obtaining the structure of the lunar IM element in the present invention. (a) to (7'l indicate the process order, and the numbers 1 to 5 in the drawings correspond to those in FIG. 1, and 6 is the resist.

First, as shown in FIG. 1(a), a bottom metal layer 2 is formed on an insulating substrate 1. A metal that can be anodized, such as tantalum or aluminum, is selected as the coating material for the lower metal.

Next, as shown in (b), a surface insulating film 4t is formed on the surface of the lower metal layer 20. Surface part iI! The 2i* film 4 is generally formed by an anodic oxidation method, but other methods include an oxidation method by high-level treatment in an oxygen atmosphere, a method of forming by sputtering of an extremely thin material, or a method of forming the film by using T, or an insulating method. A method of applying 4 to 1 fat onto the surface of the lower metal 1.1 may also be used. However, in this example, it is important to be able to emboss the surface and 4y4-etch the surface.
do. If 14 is tantalum oxide, aluminum oxide, etc., it is possible to simply etch it.Subsequently, (C
) shows the unnecessary portions of the surface insulating film 4 and the lower metal layer S2 removed by photoetching. ML, (c) t-J Resist 6 still remains on the pattern in the state before being punctured. When the state shown in (C) is 1 and the anodization for the bottom metal is 2, the state shown in (d) is obtained.

1 of the above-mentioned lower metal λ-c is also pole ~, and in the case of 2 for the lower metal
The surface part is perfect! The part in contact with the i-crotch 4 is coated with resist 6, so it is not affected by positive oxidation, and the lower gold is 1%.
Only the stepped portion of the pattern No. 2 is subjected to anodic oxidation to form the stepped portion insulating film 3. By separately forming the surface part assembly 4 for green and the stepped part disconnected line B 3 using such a method, the surface part assembly ML<1%4 of 1. j Thickness and step part cut off,
It is possible to make the B'wN of the crotch 3 different in thickness.When forming an oxide by the same anodic oxidation method to form N, its Jl!:, thickness is determined by the anodic oxidation voltage. It is approximately proportional to .Therefore, b″p? In order to increase the resistance to 8", it is necessary to increase the possibility of anodic oxidation when forming the step insulating film 8. (g) shows the powder from which the resist has been peeled off after the step insulating film 8 is formed. Finally, by forming and buttering the upper metal layer 5, the M element having the structure of the present invention is completed as shown in (a)K. This is a second example of the manufacturing process for obtaining the structure of the M-process M element in They correspond to those in the figure. First,
3. As shown in 1(g), the lower metal J+ is placed on the absolutely H substrate 1.
! form 2. Next, (/1) shows a state in which the old portion of the lower metal base 2 has been removed using a photoetching method, and the resist 6 remains on the pattern in an unpeeled state. Subsequently, anodic oxidation is performed in the state shown in (h) to obtain the state shown in (I)K. In (i),
A cavity 3 is formed in the step part of the pattern of the lower metal part 2 due to internal packing, but since the surface part of the lower metal part 2 is retained by the resist 6, no I+r is formed. It has not been. Here, when the resist is peeled off, (
j) A4 the structure shown in K. Next, the surface assembly 4 is formed, and the structure shown in (&) is obtained (14). Table 1h1
In the present invention, the partial break ψRφ4 is the partial break 11B-:
Since it is larger than 8, the surface part, 1e#jna4, is the step part group I.
Even if it is formed after version 3, will it be formed first? +, step insulation Jl+:' 3 is not affected by any effect.Finally, when the soil metal 5 is formed and turned, the MIM element which is in accordance with the present invention is formed. , (As shown in AK, 5L is formed. 4. M I M element in the invention +1.
The first embodiment of the manufacturing process for making yarn and the second Inutabiyo 1's 'J' and 'J' phases are the surface part 4 and stage 4C section J, -II', is the formation order of 3, and in the first embodiment, the surface part group 4.:: &24 is formed before the side edge 3 of the step X section, and 1 is the second fruit// In example ii and i, the stepped portion E+') gall 3 is formed before the surface rupture 4.

Here, an overview and results of the dielectric breakdown voltage measured using the MIM element having up to the tip 1 of the present invention will be described. The M element used in the test drive was made of glass for the substrate, about 200 OA of tantalum for the lower metal layer, and 500 to 600 s of tantalum on the surface with polar oxidation formed on it. Tantalum oxide, anodic oxidation formed on the step surface, approximately 1 h.
50OA of tantalum pentoxide, and about 100O for earth metals.
It is constructed using chromium of A. Therefore, the thickness of the step part assembly H is 2.5 to 3 times the thickness of the surface part assembly film.
It's double. When we investigated the dielectric breakdown voltage when applying direct current to about 500 samples of the 14-engine M element due to this deactivation, we found that for about 99% of the sides of the samples, the voltage range was 17 to 19 V. It was shown that the voltage was concentrated, and there was no sample whose dielectric breakdown voltage was less than 10 V. This result shows that in the MIM element with the structure of the present invention, the dielectric breakdown voltage stably concentrates at a constant value and the frequency of occurrence of dielectric breakdown voltage defects is significantly reduced compared to the conventional M-engineered M element. It shows.

〔effect〕

As described above, according to the present invention, the i
1, j# It is possible to significantly reduce the occurrence of ridge breakage and pressure defects PL, and to manufacture M-work M2 pieces at a high product yield. In addition, in the four-structure rc of the MIM element according to the present invention, B! 1IJ1:' is larger than that of conventional MIM elements, so the mechanical strength of the gap side is also stronger than before.

Therefore, the present invention 1f-blr IilIM element 1
It is stronger and more stable than the conventional MIM resistor. In this way, the Vri invention provides an MIM element that is both short-tempered and mechanically robust. The effect of the present invention is particularly significant when applied to fields where a large number of M-engine M elements formed in soil all operate normally.

[Brief explanation of the drawing]

FIG. 1 shows part of the invention: J! :M5. MI in example
A diagram showing a cross-sectional structure of an M element. FIGS. 2(iz) to U1 are diagrams showing one manufacturing process for obtaining the structure of the MIM element in the present invention. Figures 3 (a) to ω show other manufacturing steps for obtaining the structure of the M element in the present invention. Part insulating film 4... Receiving surface side k R+J 5... Earth metal 6, e, resist (Applicant fi'l Co., Ltd.)! Visiting Hako Koso Attorney, Patent Attorney Doma Jomu f, ``S1 Diagram

Claims (1)

[Claims] 1. Forming and battering a lower metal FA on an insulating substrate, then forming an insulating film on the surface of the lower metal area, and patterning the lower metal area. In a nonlinear resistance element formed by forming and patterning in a shape that intersects with the shape, the parent thickness of the insulating film formed at the pattern step part of the lower metal area is It is characterized by being thicker than the insulating film formed on the part. FL film non-film type linear resistance element, characterized in that the insulating film formed on the pattern step portion of the lower metal region is a metal oxide film formed by oxidizing the lower metal region by an anodizing method. The 'mk non-ξ square shaped resistance element according to item 1. 3. The insulating film formed on the pattern step part of the lower metal area is 1
000 to 200 OA tantalum oxide film, Claim 1 or 2 +14 (
of? lli membrane nonlinear gyantai, child. 4. The removal of p7 of the insulating film formed on the step part of the pattern on the bottom metal is completely removed on the surface of the pattern on the bottom metal. RI () supination section 1 and section 2 JJ''1 of the patent claim characterized in that it is 2 to 4 times as large as JJ''1
Or the dynamic nonlinear resistance element described in item 3.