JPH0738060A - Film-type capacitor and its trimming method - Google Patents

Abstract

PURPOSE:To provide a film-type capacitor suitable for a high frequency circuit and besides capable of high-speed trimming by a laser beam too, and a trimming method for the film-type capacitor. CONSTITUTION:In a film capacitor equipped with counter electrodes 5 and 7 counterposed integrally through a dielectric layer 6, at least one counter region each of the electrode layers 5 and 7 is fractionated 6a and 7a, and besides connection conductors 5b and 7b for the fellow fractionated electrode layers 5a and 7a are arranged asynchronously between counter faces, and also the connection conductors 5b and 7b for the fellow fractionated electrode layers 5a and 7a of the film-type capacitor are cut off electrically by selectively applying a laser beam, thus the capacitor is trimmed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film type capacitor and a method for trimming the same, and more particularly, to a dielectric layer which does not affect the electrical characteristics of the capacitor even if the dielectric layer is damaged. The present invention relates to a film capacitor to which laser light trimming can be applied and a trimming method thereof.

[0002]

2. Description of the Related Art Membrane capacitors such as chip capacitors have been put to practical use as components of various electronic circuit devices. That is, as shown in the cross-sectional view of the main part structure in FIG. 3, a first metal-based electrode layer 2, a dielectric layer 3, and a second metal-based electrode layer 2 are formed on a surface of a substrate 1 made of, for example, Si, sapphire, or ceramics. A film type capacitor having a structure in which the electrode layers 4 are sequentially laminated is known. In the structure of this film type capacitor, both metal-based electrode layers 2 and 4 are, for example, Au / NiCr, Au / Ti / NiC.
r, Au / Pt / Ti / NiCr, Au / Ni / Cr / NiCr, Al or the like, which are formed by a vapor deposition method, a sputtering method, a plating method or the like. The dielectric layer 3 is made of, for example, BaSrTiO ₃ , SrTiO ₃ , Ta ₂ O ₅ , SiO _2.
2 and Al ₂ O ₃ are formed by bias sputtering or CVD. And these patterning
It is performed by a selective vapor deposition method or a sputtering method using a mask or the like, or a selective photoetching treatment.

On the other hand, in the film type capacitor having the above structure, the size and shape of the metal-based electrode layers 2 and 4 and the material and thickness of the dielectric layer 3 are set in accordance with the specifications, standards and designs according to the application. However, the capacitance value of the product varies in reality. Therefore, the capacitance value of the film type capacitor is measured prior to incorporation into a mounting circuit or the like, and if necessary, trimming processing using laser light or the like is performed to adjust the capacitance value of the film type capacitor.

[0004]

By the way, in the trimming of the film type capacitor, the capacitance value is reduced by volatilizing and cutting off a part of the metal-based electrode layers 2 and 4 to appropriately reduce the region functioning as a capacitor. Is a means for setting arbitrarily. When laser light is used as a heat source for separating or volatilizing / cutting off a part of the metal-based electrode layers 2 and 4, so-called beam irradiation is possible.
While it has the advantage of being relatively easy to make fine adjustments, it also has the following inconvenient problems. That is, of the metal-based electrode layers 2 and 4 disposed with the dielectric layer 3 sandwiched therebetween, for example, an upper electrode layer (second metal-based electrode layer) 4 has a laser (beam) whose power is appropriately adjusted. The electrode layer 4 is irradiated with light.
When a part of the above is removed by trimming, although the power of the irradiation laser is finely adjusted, the dielectric layer 3 in the irradiation region of the laser light or in the vicinity thereof is deteriorated.

More specifically, the dielectric layer 3 located below or in the vicinity of the electrode layer 4 irradiated with the laser beam will have microcracks or the removed metal component will invade the dielectric layer 3 to some extent. (Diffuse) or cause a change in crystalline state. Then, the partial deterioration of the dielectric layer 3 is caused by (a) an increase in current leakage between the two electrode layers 2 and 4, (b) a decrease in withstand voltage of the film type capacitor, (c) a temperature coefficient (TCR) of the capacitance value. Change and (d) increase in capacitance value over time, resulting in a loss of yield and reliability. Such a problem must be said to be a serious problem, for example, against the current situation that film capacitors used as components in high-frequency matching circuits are required to have higher performance and higher reliability. .

The present invention has been made in consideration of the above circumstances, and an object thereof is to provide a film type capacitor suitable for a high frequency matching circuit or the like and capable of high-speed trimming by a laser beam, and a method for trimming a film type capacitor. To do.

[0007]

Means for Solving the Problems A film type capacitor according to the present invention is a film type capacitor comprising a counter electrode layer integrally disposed via a dielectric layer, wherein at least one of the electrode layers is provided. The opposing region of the part is subdivided, and the connecting conductors of the subdivided electrode layers are arranged asymmetrically between the opposing faces, and the method for trimming a film capacitor according to the present invention is In the laser light trimming of a film capacitor comprising an opposing electrode layer integrally disposed via a layer, at least a portion of the opposing region of the electrode layer is subdivided, and the subdivided electrode layer The connecting conductors of each other are asymmetrically arranged between the facing surfaces, and the connecting conductors of the subdivided electrode layers that are asymmetrically arranged between the facing surfaces are selectively irradiated with laser light. Electrical Disconnected, characterized in that trimming the capacitor.

The film capacitor according to the present invention uses a thin plate of, for example, Si, sapphire, or ceramics as a substrate, and a first metal-based electrode layer (lower electrode layer), a dielectric layer, and A second metal-based electrode layer (upper electrode layer) facing the first metal-based electrode layer is formed in a laminated manner. The above-mentioned both metal-based electrode layers are, for example, Au / NiCr, Au / Ti / NiCr, Au / Pt / Ti.
/ NiCr, Au / Ni / Cr / NiCr or Al, which are formed by a vapor deposition method, a sputtering method, a plating method, or the like.

The dielectric layer 3 is made of, for example, BaSrTi.
It is formed by bias sputtering of O ₃ , SrTiO ₃ , Ta ₂ O ₅ , SiO ₂ , Al ₂ O _3, etc. That is, the structure is basically the same as in the case of the conventional film type capacitor, but at least a part of the opposing regions of the opposing electrode layers is electrically controlled as a region for finely adjusting the capacitance value. It is characterized in that it is subdivided in the state of being connected to each other, and the connection conductors of the subdivided electrode layers are asymmetrically arranged between the facing surfaces. Further, in the trimming method, in the film type capacitor having the above-mentioned configuration, the connecting conductor of the electrode layers, at least a part of which is subdivided, is selectively irradiated with laser light and cut to electrically cut off the capacitance value. The idea is to make fine adjustments.

[0010]

The above-mentioned membrane capacitor according to the present invention functions as a so-called capacitance value adjusting portion by subdividing at least a part of the electrode layers facing each other and connecting the subdivided electrode layer portions with conductors. In addition, the conductors that connect the subdivided electrode layer portions are asymmetrically arranged between the facing surfaces. That is, the film capacitor is provided with a capacitance value adjusting unit in advance, and by electrically cutting off a part of the connection conductors in the capacitance value adjusting unit in order to eliminate the capacitor function of the subdivided electrode layer unit. , The capacitance value can be finely adjusted arbitrarily.
Moreover, when a laser beam is radiated to electrically cut a part of the connection conductors sequentially, an electrode layer functioning as a capacitor does not exist on the facing surface radiated with the laser beam. Erroneous problems caused by deterioration of the dielectric layer due to irradiation, in other words, current leakage between both electrode layers, reduction of breakdown voltage, change of temperature coefficient (TCR) of capacitance value, change of capacitance value over time, etc. are easily solved, A film type capacitor suitable for high frequency matching circuits and capable of high-speed trimming by laser light is provided.

[0011]

EXAMPLE An example of the present invention will be described below with reference to FIGS. 1 (a), 1 (b) and 2, which show an example of the essential structure of a film capacitor according to the present invention.

FIGS. 1 (a) and 1 (b) are plan views of a main part of a different configuration example of a film type capacitor, and FIG. 2 is a line AB of FIG. 1 (a).
It is sectional drawing which followed the line. 5 in FIGS. 1 (a) and 1 (b)
Is a second metal-based electrode layer (upper electrode layer) forming the main capacitor portion, and 5a is the second metal electrode layer forming the main capacitor portion.
Is a subdivided electrode layer electrically connected to each of the metal-based electrode layers 5 through the connecting conductors 5b, and these are formed of, for example, Au / NiCr layers. Reference numeral 6 denotes a dielectric layer, for example, an SrTiO ₃ layer, which has a pattern facing the second metal-based electrode layer 5 and the subdivided electrode layer 5a forming the main capacitor portion, and is formed, for example, on a ceramic substrate (not shown). The first metal-based electrode layer (lower electrode layer) 7 forming the main capacitor portion disposed in
Of the metal-based electrode layer 7 and the subdivided electrode layer 7a electrically connected to each other through the connecting conductors 7b. In the above structure, the metal-based electrode layers 5 and 7 forming the main capacitor portion and the subdivided electrode layers 5a and 7a
The conductors (patterns) 5b and 7b that connect to and are arranged asymmetrically between the facing surfaces. That is, FIG.
As shown in a sectional view in FIG. 3, the connection conductors 5b and 7b for connecting the metal-based electrode layers 5 and 7 and the subdivided electrode layers 5a and 7a are
They are in a dislocated arrangement / position relationship. In FIG. 2, 8 is a ceramic substrate as a supporting substrate.

In the above description, the membrane type capacitor is divided into a region forming the main capacitor portion and a region for adjusting the capacitance value (region in which the electrode layer is subdivided). When the region is subdivided, it can be used as a film type capacitor having an arbitrary capacitance value, for example, by appropriately cutting and separating between the subdivided electrode layers. Further, the subdivision of the electrode layer constituting the capacitor for adjusting the capacitance value, in other words, the size and shape of the subdivided electrode layer, the distance between the subdivided electrode layers, etc., depend on the accuracy required for the film capacitor. It is possible to select and set arbitrarily, and further,
The film type capacitor may have a so-called single plate structure in which the electrode layers are exposed on both sides without using a supporting substrate.

The thin film capacitor as described above is
For example, it can be provided by being mounted on the substrate of the circuit device or directly formed on the substrate.

Next, the trimming of the film type capacitor having the above structure will be described. For example, in the case of trimming a film type capacitor having a configuration shown in plan view in FIG. 1 (a) with a laser beam, a conductor that connects the electrode layers 5 and 7 forming the main capacitor portion and the subdivided electrode layers 5a and 7a. Five
Any of the ones for connecting the electrode layer 5 and the subdivided electrode layer 5a with a laser beam whose power is set in advance in consideration of the thickness of b and 7b, the type of metal, the thickness and composition of the dielectric layer 6, and the like. The conductor 5b is irradiated and cut to electrically cut the electrode layer 5 and the subdivided electrode layer 5a connected by the conductor 5b. That is, the capacitance of the capacitor that is composed of the electrically cut electrode layer 5a and the corresponding electrode layer 7a is reduced, and the capacitance value is reduced / adjusted by at least that much. Further, when it is necessary to reduce or adjust the capacitance value, the electrode layer 5 and other subdivided electrode layers 5a
By sequentially irradiating and cutting a laser beam on the conductor 5b for connecting with the conductor 5b, and electrically cutting the electrode layer 5 and the subdivided electrode layer 5a connected by the conductor 5b, It is possible to reduce and adjust the required capacity value. Further, at this time, the subdivided electrode layer corresponding to the subdivided electrode layer 5a which is electrically cut
It is also possible to irradiate the conductor 7b connecting the 7a and the electrode layer 7 with a laser beam to cut the conductor.

By the way, in the capacitance value trimming of the film type capacitor, the electrode layers 5 and 7 and the subdivided electrode layers 5a and 7a are irradiated with a laser beam to form conductors 5b and 7b.
When the laser beam is cut off and electrically cut off, even if the dielectric layer 6 in the laser beam irradiation region or its vicinity is partially deteriorated, this deteriorated region is out of the region functioning as a capacitor, so the capacitance value is adjusted. Done (trimmed)
The possibility that the characteristics of the film type capacitor may be adversely affected is eliminated. In other words, current leakage between electrode layers, breakdown voltage reduction, temperature coefficient (TCR) change of capacitance value, change of capacitance value over time, etc. are eliminated and avoided, and a film with stable characteristics that always exhibits a function suitable for high frequency matching circuits, for example. It becomes possible to trim to a mold capacitor.

The film type capacitor and the trimming method therefor according to the present invention are not limited to the above-described exemplary embodiment, and can be variously modified without departing from the gist of the present invention. Is. For example, the electrodes may be of the film thickness type, and the electrode layers other than the connecting conductors do not necessarily have to be symmetrically opposed to each other.

[0018]

As described above, according to the present invention, the film type capacitor is provided with the capacitance value adjusting portion in advance, and a part of the connecting conductor in the capacitance value adjusting portion is electrically cut off sequentially to be subdivided. By eliminating the capacitor function of the electrode layer portion, the capacitance value can be finely adjusted arbitrarily. Then, when a part of the connection conductor is sequentially electrically cut by irradiation with laser light, there is no electrode layer functioning as a capacitor on the opposing surface irradiated with the laser light, and thus the dielectric accompanying the irradiation with the laser light is not present. The adverse effects resulting from the deterioration of the body layer are completely eliminated and avoided. In other words, inconvenient problems such as current leakage between opposing electrode layers, lowering of breakdown voltage, change of temperature coefficient (TCR) of capacitance value, and change of capacitance value with time are easily and surely solved, and it is suitable for high frequency matching circuit and the like, and laser A film type capacitor capable of high-speed trimming by light is provided.

[Brief description of drawings]

1A and 1B are plan views showing configuration examples of different main parts of a film capacitor according to the present invention.

FIG. 2 is a sectional view taken along the line AB of FIG.

FIG. 3 is a cross-sectional view showing a configuration of a main part of a conventional film capacitor.

[Explanation of symbols]

1, 8 ... Support substrate 2, 7 ... First metal-based electrode layer (lower electrode layer) 3, 6 ... Dielectric layer 4,5 ... Second metal-based electrode layer (upper electrode layer) 5a, 7a ... Subdivision Electrode layers 5b, 7b ... Connection conductor parts

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H01L 27/01 321

Claims (3)

[Claims] 1. A film capacitor comprising a counter electrode layer integrally arranged via a dielectric layer, wherein at least a part of the counter region of the electrode layer is subdivided.
A film-type capacitor characterized in that connecting conductors of the subdivided electrode layers are arranged asymmetrically between opposed surfaces. 2. A circuit device in which a film-type capacitor having a counter electrode layer integrally arranged via a dielectric layer is mounted or formed on an insulating substrate, wherein at least a part of the electrode layer is provided. The opposing area is subdivided, and the connecting conductors of the subdivided electrode layers are arranged asymmetrically between the opposing surfaces, and at least one of the connecting conductors is trimmed to disconnect the electrical connection. A circuit device characterized by the above. 3. In a laser light trimming of a film type capacitor comprising a counter electrode layer integrally arranged via a dielectric layer, at least a part of the counter region of the electrode layer is subdivided,
In addition, the connection conductors of the subdivided electrode layers are arranged asymmetrically between the facing surfaces, and the connection conductors of the subdivided electrode layers are arranged asymmetrically between the facing surfaces. A method for trimming a film type capacitor, which comprises irradiating a laser beam electrically and electrically cutting the capacitor to trim the capacitor.