JPH03200310A - Laminated thin-film dielectric element and manufacture thereof - Google Patents

Abstract

PURPOSE:To enable forming the title dielectric element according to a thin film thickness by forming double electrode films having SnO2 thin film on the front and Cr, Ni or Cu thin film on the rear and further TiO2 dielectric thin films through causing these films to make an epitaxial growth respectively by means of vapor deposition and by laminating these two sorts of films alternately. CONSTITUTION:A part or the whole of plural layers of double electrode films 2, 3, as internal electrode layers for obtaining capacity, is composed of at least 2 groups connected with lead-out ends differing from each other. In this case, the double electrode films 2, 3 belonging to the same group are respectively taken out to the same side end and connected with the terminal electrode 20 of Cu or Ni arranged or formed at the side end and having Ni metallic deposit 21 on the surface. Thus, a low-cost glass substrate 1 is used so that internal electrode thin films can alternately be laminated on the glass substrate according to a thin thickness while holding dielectric thin films between them.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thin film dielectric element having a laminated structure and a method for manufacturing the same.

[Conventional technology] Conventionally, ceramic multilayer capacitors have been widely used as dielectric elements with small size and large capacity.In chip-type multilayer capacitors without lead wires, capacitance is obtained by sandwiching thin dielectric ceramic layers. Internal electrode layers are alternately stacked to face each other, and the terminal ends of the internal electrodes are connected to external terminal electrodes that can be directly soldered.

In order to increase the acquisition capacity of the element in this multilayer capacitor, attempts are usually made to reduce the thickness of each dielectric layer. However, in the case of multilayer ceramic capacitors, in order to realize a ceramic dielectric layer with a thickness of 10 mm or less, there are many steps such as creating a thin green sheet, sheet attack of electrode paste, pressure molding, and controlling the particle size of dielectric particles after firing. difficult technical challenges,
At present, no ceramic multilayer capacitor with a dielectric layer thickness of less than 5 mm has been announced.

On the other hand, using vapor deposition techniques such as vapor deposition and sputtering,
Attempts have been made to fabricate thin film capacitors with high capacitance, but thin films based on ferroelectric materials such as barium titanate and lead-based perovskite, which can be expected to obtain high capacitance, have a crystalline phase when passing the Curie point. Good quality dielectric thin films have not been obtained due to the problem of distortion caused by dislocation. In addition, in order to avoid the problem of distortion that occurs during this crystal phase transition, there is a method of epitaxial growth from a base substrate, but the base substrate is made of an expensive single crystal (for example, SrTiO3, PT, etc.).
Since it is limited to , there is no prospect of practical application.

[Problems to be Solved by the Invention] As mentioned above, despite various studies being conducted to meet the demand for further miniaturization of multilayer ceramic capacitors, products with a dielectric film thickness of less than 51 μmm have not been produced. It has not yet been put to practical use, and even thin film capacitors using vapor deposition have the drawbacks mentioned above. Therefore, there has been no technology for simply laminating high-quality dielectric films to a thickness of 10 m, preferably less than 5 Ra, at low cost.

An object of the present invention is to provide a laminated thin film dielectric element formed of a dielectric thin film having a thickness of less than 1 urn, preferably less than 5 urn, without using an expensive single crystal substrate.

[Means and effects for solving the problem] In order to achieve the above object, the present inventors conducted research and found that they used an inexpensive glass substrate and deposited a thin film of SnO on the surface and a carbon film on the back surface using an evaporation method.
r, double electrode film with Ni or Cu thin film (hereinafter referred to as Sn
By epitaxially growing an O2/(Cr, Ni or Cu) double electrode film and a TiO2 dielectric thin film, and alternately stacking these two types of films, a conventional multilayer ceramic capacitor can be formed. It has a similar structure and a film thickness of 10m, preferably 5D.
The present inventors have discovered that it is possible to obtain a laminated thin-film dielectric element that is thinner than the above-described method and can be made thinner to about lumen.

That is, the present invention first provides a laminated thin film dielectric element as described below.

On the glass substrate, SnO2 thin film on the front side and Cr5N on the back side
A basic structure in which dual electrode films with a thickness of 1 or Cu thin films having a thickness of to, less than 5 ccm, preferably less than 5 cm, and TiO2 dielectric films with a thickness of less than 10 Il, preferably less than 5 m are laminated alternately. A part or all of the plurality of double electrode films has at least two layers connected to different lead-out ends as internal electrode layers for obtaining capacitance.
The double electrode films belonging to the same group are each drawn out to the same side edge and connected to a Cu or Ni terminal electrode arranged or formed on the side edge and having a Ni plating layer on the surface. A multilayer thin film dielectric element characterized by:

Second, the present invention provides a method for manufacturing a laminated thin film dielectric element as described below.

(b) SnO with a thickness of 10 um or less, preferably 5 um or less, having a predetermined shape and area by CVD on a glass substrate.
2/((:r, Ni or Cu) double electrode film (S on the surface
A double electrode film having an nO2 thin film and a Cr5Ni or Cu thin film on the back surface is formed, and unnecessary portions are removed by wet etching to form a first Sn02/CCr,
(Ni or Cu) double electrode film (1); (b) On this SnO2/(Cr, Ni or Cu) double electrode film (1), epitaxial growth is performed on the base SnO2 film by CVD method to form a thick layer. less than 101 tla,
Preferably, a TiO2 dielectric film with a thickness of 5IIIa or less is formed, and unnecessary portions are removed by dry etching to form the first film.
Assume that the TiO2 film (1) is; (c) the above TiO2 film (
1) is epitaxially grown by the CVD method to a thickness of 1oI11a or less, preferably 5ura or less.
A double electrode film of O2/(Cr, Ni, or Co) is formed, and unnecessary portions are removed by wet etching to form a second Sn02/(Cr, Ni, or Co).
';Single electrode film (Watoshi);(d)The above SnO2/(Cr
, Ni or Cu) on the double electrode film (2) in the same manner as in (2), and after repeating all or part of the above (a) to (d),
A portion of the side edges of the laminate is cut and removed so that the ends of the plurality of double electrode films appear on the cut surface, and N is applied to the surface of the cut surface.
The following dielectric element consists of forming a Cu or Ni terminal electrode with an i-plated layer, i.e., a glass substrate with a SnO thin film on the front surface and a Cr5Ni or Cu thin film on the back surface with a thickness of 10 μm or less, preferably 511
! A double electrode film of less than a and a thickness of less than 10 m, preferably 5
It has a basic structure in which TiO2 dielectric films of 11M or less are laminated alternately, and some or all of the plurality of double electrode films are used as internal electrode layers to obtain capacitance. It consists of at least two groups connected to the ends, and the double electrode films belonging to the same group are each drawn out to the same side end, and the Cu layer having a Ni plating layer on the surface is disposed or formed on the side end. Or a method for manufacturing a laminated thin film dielectric element, characterized in that the element is connected to a Ni terminal electrode.

FIG. 1 is a schematic cross-sectional view showing the film formation order in manufacturing the laminated thin film dielectric element of the present invention. As shown in FIG. Cu) dual electrode films and TiO2 dielectric films are alternately laminated, external terminal electrodes are provided at both ends of the thin film, and internal electrodes of SnO2/(CrSNi or Cu)2
It has a structure in which the heavy electrode film is drawn out, and has a structure similar to that of a conventional multilayer ceramic capacitor.

Further, in order to improve adhesion to the glass substrate or dielectric film, a thin film made of any one of Cr, Ni, and Cu was disposed on the back surface of the electrode film to form a double film structure. Therefore, by forming the above-described laminated structure using an inexpensive glass substrate, the 101
It is now possible to provide a laminated thin film dielectric element having a dielectric film thinner than 500 nm, preferably less than 500 nm.

The present invention will be further explained below with reference to Examples.

[Example 1] The manufacturing order of the laminated thin film dielectric element of the present invention will be explained according to the above-mentioned FIGS. 1(a) to (h).

(a) Borosilicate glass substrate (Corning #705
9) A double electrode film consisting of a surface layer of SnO □ film 3 and a back layer of Cr film 2, each having a thickness of 0.5 mm, is formed on 1.
One end of this SnO2/Cr double electrode film was removed by wet etching, and the SnO2/Cr double electrode film (
1).

(b) A TiO2 film 4 is epitaxially grown on the base SnO2 film 3 by the CVD method on the double electrode film (1).
The TiO2 dielectric film 2 is formed to have a thickness of 100 cm.

(c) This TiO2 dielectric film ■ has SnO2 as described above.
A /Cr double electrode film 5 was formed with a thickness of 0.5 zcm each, and one end of the film was removed by wet etching to form an Sn
O2/Cr double electrode film (Tsutsuto).

(d) Next, the TiO2 film 6 is coated with SnO as an underlayer by CVD method.
TiO2! is formed by epitaxial growth to a film thickness of 1. ! ! Dielectric film (Tsutsuto. At this time,
The TiO2 dielectric film (the TiO2 dielectric film (2) is directly bonded to the TiO2 dielectric film (2) and has a shape that covers one end of the SnO2/Cr double electrode film (2).

(e) Furthermore, TiO, dielectric film (S
The n 02 /Cr double electrode film 7 has a film thickness of 1 urm (
A SnO2/Cr double electrode film
And so.

(f) Furthermore, the TiO2 film 8 is coated with SnO as an underlayer by CVD method.
Two films were formed with a thickness of 1 ilpa by epitaxial growth to form a TiO□ dielectric film ■.

At this time, the TiO2 dielectric film (2) is directly bonded to the TiO2 dielectric film (2) and has a shape that covers one end of the SnO2/C double electrode film (2).

(g) On the laminated film obtained from the above steps, a SnO2/Cr double electrode film 9 as described above is formed to a film thickness of 1111 m (each film thickness 0.5 ItIa), and one end was removed by wet etching method to form SnO□/Cr
double electrode film).

(h) By repeating the steps (a) to (g) above, T
A laminated film was formed in which SnO2/Cr double electrode films were patterned alternately with iO2 dielectric films in between.

(i) Next, the sample was cut along the imaginary line shown in FIG. 4(g) to expose the electrodes on the cross section.

(j) A Cu paste was applied to the cut surface and baked at 500°C for 2 hours in a nitrogen atmosphere to form a Cu terminal electrode 20 as shown in (h) of the figure.

Furthermore, a Ni layer 21 is formed on this terminal electrode 20 by plating.
was formed.

By this method, the highest capacitance can be obtained when comparing the same number of laminated layers.

[Example 2] The manufacturing order of the laminated thin film dielectric element of the present invention will be explained according to FIGS. 2(a) to 2(g).

(a) Borosilicate glass substrate (Corning #705
9) A double electrode film consisting of the surface layer of the SnO2 film 3 and the back layer of the Cr film 2, each having a thickness of 0.5 m, is formed on the SnO□/C double electrode film. The SnO□/C double electrode film (1) was removed by wet etching.
).

(b) A TiO2 film 4 is epitaxially grown on the base SnO2 film 3 by the CVD method on the double electrode film (1).
The TiO2 dielectric film 2 is formed to have a thickness of 100 cm.

(c) This TiO□dielectric film■ has SnO as described above,
A /Cr double electrode 85 is formed with a film thickness of 0.5 mm each, and one end thereof is removed by wet etching to form SnO2.
/Cr double electrode film (Tsutsuto.

(d) Next, T i 02 M6 is epitaxially grown on the base SnO2 film by CVD method to a film thickness of 1 cm, and the Ti 02 dielectric film (reduced) is formed. Body membrane (TiO2 dielectric film)
The SnO2/Cr dual electrode film is directly bonded to the SnO2/Cr double electrode film (to form a shape that covers one end of the SnO2/Cr double electrode film).

(e) Furthermore, the TiO2 dielectric film
The 2/Cr dual electrode film 7 has a film thickness of μmlfa (each film thickness 0.
A film of 5m+) was formed, and one end was removed by wet etching to form an S opening 0□/Cr double electrode film ■.

(f) Further, by CVD method, the TtO□ film 8 is coated with SnO
A TiO2 dielectric film (2) was formed by epitaxial growth to a thickness of one layer for two films.

At this time, the TiO2 dielectric film ■ is TiQ, the dielectric r
The shape is such that it is directly bonded to the S n 02 /Cr double electrode film and covers one end of the S n 02 /Cr double electrode film.

(g) On the laminated film obtained from the above steps, a SnO2/Cr double electrode film 9 as described above is formed to a film thickness of 1 ilm (each film thickness 0.5za++), and one end is wetted. It was removed by an etching method to form a SnO2/Cr double electrode film).

(h) Next, a TiO2 film lO is deposited as a base S n by CVD method.
The O2 film was epitaxially grown to a thickness of 1 mm to form a T t 02 dielectric film.

At this time, the TiO2 dielectric film) is bonded to the TiO□ dielectric film method to form a shape that covers one end of the Sn02/Cr double electrode film).

(i) Further on the T i Q2 dielectric film), a SnO2/Cr double electrode film 11 as described above was formed to a film thickness of 111M (each film thickness 0.5 μm), and one end was removed by wet etching. This resulted in a SnO2/Cr double electrode film (2).

(j) Furthermore, a CvD method Niyori TiO2 film 12 is applied as a base layer S.
A T i O2 dielectric film (2) was formed by epitaxial growth on the n02 film to a thickness of one layer.

At this time, the TiO2 dielectric film (2) is bonded to the TiO□ dielectric film method so as to cover one end of the S n O2/Cr double electrode film (2).

(aSb), (cSd), (esf)(
Alternatively, all or part of the operations g, h) (or 1Sj) can be repeated, but they are omitted here.

(k) On the laminated film obtained from the above steps, the SnO2/Cr double electrode film 13 as described above is formed to a film thickness of IIIM (each film thickness 0.5IIn), and both side edges are wet etched. The SnO2/Cr double electrode film (2) was removed by the method.

(p) Next, the sample was cut along the imaginary line shown in (k) of the figure to expose the electrodes on the cross section.

Apply Cu paste to the cut surface and heat it for 500 min in a nitrogen atmosphere.
After baking for 2 hours at ℃, as shown in the same figure (R),
A u-terminal electrode 20 was formed.

Furthermore, a Ni layer 21 is formed on this terminal electrode 20 by plating.
was formed. As a result, the SnO2/Cr electrode film 13 becomes a third electrode independent of the terminal electrodes on both sides.

(m) As a result of the above, SnO2/Cr double electrodes are alternately stacked with dielectric layers made of TiO2 films in between,
and all or some of the SnO2 electrodes are connected at their ends to external electrodes provided at the ends of the element, or are assembled at the ends of the element to form three (or more) electrodes that do not touch each other. A structure was provided.

[Examples 3 to 7] In Example 1, the SnO□/Cr double electrode film formed in steps (a), (c), (e) and (g), and the Cu used in step (j) Paste each
A multilayer thin film dielectric element was manufactured by performing the same operations as in Example 1 except for the changes shown in the table.

(Margin below) Table 1 [Examples 8 to 12] In Example 2, all the SnO2/Cr double electrode films and the Cu paste used in step (j) were changed as shown in Table 2. A laminated thin film dielectric element was manufactured by performing the same operation as in Example 2.

(Margin below) Table 2 FIG.

Explanation of symbols 1...Glass substrate [Effects of the invention] As explained above, according to the present invention, although it has the same structure as a conventional multilayer ceramic capacitor, an inexpensive glass substrate is used and a It is possible to provide a laminated thin film dielectric element in which internal electrode thin films are alternately laminated with dielectric thin films sandwiched therebetween to a thickness of less than 10 mm, preferably less than 51 ua.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing the sequence of film formation in one embodiment of the laminated thin film dielectric element of the present invention. FIG. 2 shows the film formation order 4 in another embodiment of the present invention.
・TiO2 film ■ 5...Double electrode film (ri6...TiQ, film (ri7...double electrode film■ 8...TiO□ film■ 9...2 (For heavy electrode film) 10...For TiO2 film) 11...Double electrode film■ 12...TiO2 film■ 13...Double electrode film (6) 20...Cu Terminal electrode 21...Ni plating layer

Claims (2)

[Claims] (1) A basic structure in which dual electrode films with a thickness of 10 μm or less and TiO_2 dielectric films with a thickness of 10 μm or less are alternately laminated on a glass substrate, with a SnO_2 thin film on the front surface and a Cr, Ni, or Cu thin film on the back surface. structure, and part or all of the plurality of layers of dual electrode films are composed of at least two groups connected to mutually different lead-out ends as internal electrode layers for obtaining capacitance, and the same group is connected to different lead-out ends. The dual electrode films belonging to the above are each drawn out to the same side end and are connected to a Cu or Ni terminal electrode having a Ni plating layer on the surface, which is arranged or formed on the side end. Laminated thin film dielectric element. (2) (a) SnO_2/(Cr with a thickness of 10 μm or less with a predetermined shape and area by CVD method on a glass substrate,
Ni or Cu) double electrode film (SnO_2 thin film on the surface,
(Double electrode film with Cr, Ni or Cu thin film on the back side)
and remove unnecessary portions by wet etching to form a first SnO_2/(Cr, Ni or Cu) double electrode film (1); (b) this SnO_2/(Cr, Ni or Cu) double electrode film (1); On the electrode film (1), a TiO_2 dielectric film with a thickness of 10 μm or less is formed by epitaxially growing the base SnO_2 film using the CVD method, and unnecessary portions are removed by dry etching to form the first TiO_2 film. (1); (c) SnO_2 with a thickness of 10 μm or less is epitaxially grown on the TiO_2 film (1) by CVD method.
/(Cr, Ni or Cu) double electrode film is formed and unnecessary parts are removed by wet etching to form a second Sn
O_2/(Cr, Ni or Cu) double electrode film (2); (d) On top of the SnO_2/(Cr, Ni or Cu) double electrode film (2), a second layer is formed in the same manner as in (b). of TiO_
After forming two films (2) and repeating all or part of the above (a) to (d),
A portion of the side edges of the laminate is cut and removed so that the ends of the plurality of double electrode films appear on the cut surface, and N is applied to the surface of the cut surface.
The following dielectric element consists of forming a Cu or Ni terminal electrode with an i-plated layer, i.e., a glass substrate with a thickness of 10 μm or less having a SnO_2 thin film on the front surface and a Cr, Ni or Cu thin film on the back surface. It has a basic structure in which double electrode films and TiO_2 dielectric films with a thickness of 10 μm or less are laminated alternately, and a part or all of the plurality of layers of double electrode films are used as internal layers for obtaining capacitance. The electrode layer consists of at least two groups connected to different lead-out ends, and the double electrode films belonging to the same group are each drawn out to the same side edge, and the surface arranged or formed on the side edge. A method for manufacturing a laminated thin film dielectric element, characterized in that the element is connected to a Cu or Ni terminal electrode having a Ni plating layer.