JPH09312457A - Circuit board with capacitor element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a capacitor element in specific electrostatic capacitance to be formed by a method wherein, within this circuit board made of the surface of a lower part electrode layer and an upper electrode coating at least one side, a resin insulating layer is interposed in the region opposite to the angle part of surface and side of the lower part electrode layer between a dielectric layer and the upper part electrode layer. SOLUTION: Two thin film capacitor elements 3a, 3b are coat-formed on the surface of an insulating substrate 1 while the two thin film capacitor elements 3a, 3b are made of lower electrodes 5 and dielectric layers 6 coat- formed on the surface of the electrodes 5 and at least one side as well as upper part electrodes 7 coating the surface while a resin insulating matter is interposed in the region opposite to the angle part of the upper part and side of the lower part electrode layers 5. In such a constitution, a specific electrostatic capacitance decided by the permittivity of the dielectric layers 6 are formed between the lower electrodes 5 and the upper electrodes 7 so that the capacitor element in a specific electrostatic capacitance may be formed by deciding the permittivity of the dielectric layers 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit board with a capacitor mounted on a communication device such as a mobile phone or satellite communication.

[0002]

2. Description of the Related Art Conventionally, in a communication device such as a mobile phone or satellite communication, a circuit board with a capacitive element is used as a part of components constituting an electric signal transmitting / receiving circuit.

For such a circuit board with a capacitive element, an insulating board having a circuit wiring of a predetermined pattern on its upper surface is generally prepared.
It is formed by mounting a chip capacitor on the insulating substrate and electrically connecting its terminals to circuit wiring via solder or the like.

However, in recent years, communication devices such as mobile phones and satellite communications have been rapidly reduced in size and weight, and in conventional circuit boards with capacitive elements, circuit wiring is formed by a thick film forming technique such as Mo-Mn method. However, it cannot be used because the width of each circuit wiring and the gap between adjacent circuit wiring are wide, and the shape of the chip capacitor is large and the whole is large. The circuit board with the capacitive element has been required.

Therefore, it has been proposed to newly form a circuit board with a capacitive element by depositing a circuit wiring and a capacitive element on an insulating substrate by a thin film forming technique and electrically connecting the capacitive element to the circuit wiring. ing.

In such a circuit board with a capacitive element, since the circuit wiring and the capacitive element are formed by a thin film forming technique, the line width of the circuit wiring and the adjacent space are narrowed, and the shape of the capacitive element is small. It can be used for communication devices such as mobile phones and satellite communications, which are rapidly becoming lighter.

In the circuit board with the capacitive element, the circuit wiring of the circuit board is made of an electrically insulating material such as an aluminum oxide sintered body, and a thin film forming technique such as a sputtering method or a vapor deposition method is applied to the circuit board. tantalum,
It is formed by depositing a metal material such as tungsten, titanium, or chromium to a predetermined thickness, and then processing this into a predetermined pattern by photolithography technology.The thin film capacitive element is first formed by sputtering on a substrate made of an electrically insulating material. A lower electrode layer is formed by depositing α-tantalum (tantalum nitride) to a predetermined thickness by a thin film forming technique such as a method, and then a dielectric material made of tantalum oxynitride or the like is formed on the upper surface and at least one side surface of the lower electrode layer. And a metal material such as titanium-gold or nichrome-gold by a thin film forming technique such as a sputtering method or a vapor deposition method, and finally, this is processed into a predetermined pattern by an etching method to form a dielectric layer and an upper electrode layer. Is formed by.

[0008]

However, in this conventional circuit board with a capacitive element, when the dielectric is deposited on the upper surface and at least one side surface of the lower electrode layer by a thin film forming technique such as sputtering, Dielectrics cannot be applied to the corners of the upper and side surfaces of the electrode layer to a predetermined thickness, and as a result, the upper electrode layer and the lower electrode layer are electrically short-circuited, and the function as a capacitive element is exerted. Induced the drawback of not being able to.

[0009]

The present invention has been devised in view of the above-mentioned drawbacks, and an object thereof is to provide a small-sized and lightweight circuit board with a capacitive element formed by a capacitive element having a predetermined capacitance value. To provide.

The present invention is a circuit board with a capacitive element formed by forming a thin film circuit wiring and a thin film capacitive element on an insulating substrate, wherein the thin film capacitive element has a lower electrode layer, an upper surface of the lower electrode layer, and at least a lower electrode layer. A dielectric layer deposited on one side surface and an upper electrode layer deposited on the surface of the dielectric layer, and between the dielectric layer and the upper electrode layer, an upper surface of the lower electrode layer; It is characterized in that a resin insulator is interposed in a region facing a corner with a side face.

According to the circuit board with a capacitive element of the present invention,
Since the circuit wiring and the capacitive element are formed by adopting the thin film forming technology on the insulating substrate, the line width of the circuit wiring and the adjacent space are narrowed, and the shape of the capacitive element is small. It can be installed in communication devices such as mobile phones, which are rapidly advancing.

Further, according to the circuit board with a capacitive element of the present invention, the corner portion between the upper surface and the side surface of the lower electrode layer is formed between the dielectric layer and the upper electrode layer of the thin film capacitive element formed on the insulating substrate. Since the resin insulating material is interposed in the region facing the upper surface of the lower electrode layer, when the dielectric material is deposited on the upper surface and at least one side surface of the lower electrode layer by a thin film forming technique such as sputtering, Even if the upper electrode layer and the lower electrode layer are electrically short-circuited because the dielectric material does not adhere to the corners to a predetermined thickness, the short circuit is effectively prevented by the resin insulator, and as a result, the capacitance of the thin film capacitive element is reduced. It becomes possible to exhibit a predetermined function as an element.

Furthermore, since the resin insulating material interposed between the dielectric layer and the upper electrode layer of the thin film capacitive element has a low dielectric constant, the capacitance value of the thin film capacitive element greatly varies due to the resin insulating material. Therefore, the capacitance value of the thin film capacitive element can be set to a predetermined value.

[0014]

Next, the present invention will be described in detail with reference to the accompanying drawings. 1 and 2 show an embodiment of a circuit board with a capacitance element of the present invention, 1 is an insulating substrate, 2 is thin film circuit wiring, and 3a and 3b are thin film capacitance elements.

The insulating substrate 1 is made of an electrically insulating material such as an aluminum oxide sintered body, a mullite sintered body, a silicon carbide sintered body, an aluminum nitride sintered body, and a glass ceramic sintered body. In the case of using an aluminum oxide sintered body, an appropriate organic solvent or solvent is added to and mixed with a raw material powder of aluminum oxide, silicon oxide, magnesium oxide, calcium oxide or the like to form a sludge, and this is well-known to doctors. A ceramic green sheet (ceramic green sheet) is obtained by forming into a sheet shape by a blade method or a calendar roll method, and then the ceramic green sheet is subjected to an appropriate punching process to obtain a predetermined shape and at a temperature of about 1600 ° C. It is manufactured by firing.

The insulating substrate 1 acts as a supporting member for supporting the thin film circuit wiring 2, the thin film capacitive elements 3a and 3b, and the like, and the thin film circuit wiring 2 having a predetermined pattern and two thin film capacitors having a predetermined electrostatic capacitance value on the upper surface thereof. The elements 3a and 3b are adhered and formed.

The thin film circuit wiring 2 adhered and formed on the upper surface of the insulating substrate 1 is attached to the other electronic parts such as the semiconductor element 4 on which the thin film capacitor elements 3a and 3b are mounted on the upper surface of the insulating substrate 1. Connect, or thin film capacitive elements 3a, 3b
Also, it serves to electrically connect the semiconductor element 4 to an external electric circuit.

The thin film circuit wiring 2 is composed of, for example, an adhesion layer made of titanium, chromium, nickel-chromium alloy, etc., a barrier layer made of nickel, palladium, platinum, etc., and a main conductor layer made of gold, copper, etc. It has a three-layer structure, and each of the above metals is sequentially layered on the upper surface of the insulating substrate 1 by a thin film forming technique such as an ion plating method, a sputtering method, a plating method, or a vapor deposition method. The respective layers are processed into a predetermined pattern by a photolithography technique to be formed in a predetermined pattern on the insulating substrate 1.

Further, since the thin film circuit wiring 2 is formed on the insulating substrate 1 by adopting a thin film forming technique, the thin film circuit wiring 2 can be formed on the insulating substrate 1 with a high density by setting the line width and the adjacent space to be extremely narrow. The insulating substrate 1 on which the thin film circuit wiring 2 is adhered and formed can be miniaturized.

Further, two thin film capacitive elements 3a and 3b are adhered and formed on the upper surface of the insulating substrate 1, and the two thin film capacitive elements 3a and 3b are, for example, as shown in FIG. A lower electrode layer 5 made of tantalum), a dielectric layer 6 made of tantalum oxynitride or the like deposited on the upper surface and at least one side surface of the lower electrode layer 5, and a surface of the dielectric layer 6 covered. The upper electrode layer 7 and the upper electrode layer 7 are attached to each other, and a constant capacitance determined by the relative dielectric constant of the dielectric layer 6 is formed between the lower electrode layer 5 and the upper electrode layer 7. .

The lower electrode layers 5 of the two thin film capacitive elements 3a and 3b are connected to, for example, the thin film circuit wiring 2, and the upper electrode layer 7 is an electrode of the semiconductor element 4 or another thin film circuit wiring 2.
To a predetermined electric circuit.

To deposit the two thin film capacitive elements 3a and 3b on the upper surface of the insulating substrate 1, first, the lower electrode layer 5 is deposited on the insulating substrate 1. This lower electrode layer 5 is formed of, for example, α
-Tantalum (tantalum nitride), the α-tantalum is deposited on the insulating substrate 1 to a predetermined thickness (250 angstroms to 10000 angstroms) by adopting a thin film forming technique such as a sputtering method or an ion plating method. This is formed on the insulating substrate 1 by processing it into a predetermined pattern by a photolithography technique.

If the thickness of the lower electrode layer 5 made of α-tantalum is less than 250 Å, it will be difficult to firmly bond the lower electrode layer 5 to the insulating substrate 1, and if it exceeds 10,000 Å, the lower electrode layer 5 will be difficult to bond. When the layer 5 is deposited on the insulating substrate 1, a large stress is internally present inside the lower electrode layer 5, and the internal stress tends to cause the lower electrode layer 5 to peel off from the insulating substrate 1.
Therefore, the lower electrode layer 5 made of α-tantalum preferably has a thickness in the range of 250 Å to 10000 Å.

Next, a dielectric made of, for example, tantalum oxynitride is deposited to a predetermined thickness on the upper surface and at least one side surface of the lower electrode layer 5 by a thin film forming technique such as sputtering, and a predetermined pattern is formed by a photolithography technique. Then, the dielectric layer 6 is formed. The dielectric layer 6 has a function of forming a predetermined capacitance between the lower electrode layer 5 and the upper electrode layer 7, and has a thickness of 2000 angstroms or more on the upper surface and at least one side surface of the lower electrode layer 5.
It is deposited to a thickness of 10,000 Angstroms.

Finally, by depositing an upper electrode layer 7 on the surface of the dielectric layer 6 and arranging the dielectric layer 6 between the upper electrode layer 7 and the lower electrode layer 5 described above, The thin film capacitive elements 3a and 3b having a capacitance value are deposited and formed on the insulating substrate 1 at predetermined positions.

The upper electrode layer 7 is formed, for example, by laminating two layers of metal materials such as a titanium layer and a gold layer, a nichrome layer and a gold layer, and a thin film forming technique such as a conventionally known vapor deposition method or sputtering method. And on the surface of the dielectric layer 6 by applying photolithography technique.

When the upper electrode layer 7 is formed of, for example, a titanium layer and a gold layer, the titanium layer is the upper electrode layer 7.
Is firmly adhered onto the dielectric layer 6, and if the thickness is less than 250 Å, the upper electrode layer 7
Is difficult to adhere firmly onto the dielectric layer 6, and if it exceeds 10,000 angstroms, when the upper electrode layer 7 is adhered onto the dielectric layer 6, a large stress is internally generated in the upper electrode layer 7. However, the insulation stress and the withstand voltage characteristics of the thin film capacitive elements 3a and 3b tend to deteriorate due to the internal stress. Therefore, the thickness of the upper electrode layer 7 is preferably set in the range of 250 Å to 10000 Å.

The gold layer of the upper electrode layer 7 acts as a main conductor layer of the upper electrode layer 7, and if the thickness is less than 0.3 μm, the upper electrode layer 7 and the thin film circuit wiring 2 which will be described later are bonded. When connecting via the wire 8, the reliability of the electrical connection between the upper electrode layer 7 and the bonding wire 8 tends to be low, and when the thickness exceeds 5 μm, a large stress is internally generated when the gold layer is formed. However, the insulation stress and the withstand voltage characteristics of the thin film capacitive elements 3a and 3b tend to deteriorate due to the internal stress. Therefore, the gold layer has a thickness of 0.3.
It is preferably set in the range of μm to 5 μm.

Since the lower electrode layer 5, the dielectric layer 6 and the upper electrode layer 7 constituting the thin film capacitive elements 3a and 3b are all formed by the thin film forming technique, the overall shape is small and small. It can be installed in communication devices such as mobile phones, which are rapidly becoming lighter.

As shown in FIG. 2, each of the above-mentioned thin film capacitive elements 3a and 3b faces the corner between the upper surface and the side surface of the lower electrode layer 5 between each dielectric layer 6 and the upper electrode layer 7. A low-dielectric-constant resin insulator 9 is interposed in the region to be covered, and the dielectric substance is applied to the upper surface and at least one side surface of the lower electrode layer 5 by a thin film forming technique such as a sputtering method. When forming the body layer 6, the lower electrode layer 5
Dielectric material does not adhere to the corners of the upper and side surfaces of the
Even if the upper electrode layer 7 and the lower electrode layer 5 are electrically short-circuited, the short circuit is effectively prevented, and as a result, each of the thin film capacitive elements 3a and 3b can exhibit a predetermined function as a capacitive element. it can.

Further, since the resin insulator 9 has a low relative permittivity, the capacitance values of the thin film capacitive elements 3a and 3b do not greatly vary depending on the relative permittivity of the resin insulating material, and the thin film capacitive element 3a, It is possible to set the capacitance value of 3b to a predetermined value.

As the resin insulator 9, for example, fluorine resin, polyphenylene ether resin or the like having a relative dielectric constant of 3 is used.
An electrically insulating organic resin having a room temperature (1 MHz) or less is preferably used, and a resin precursor such as a fluorine resin is applied to a region facing the corners of the upper surface and the side surface of the lower electrode layer 5, and thereafter, Is cured between the dielectric layer 6 and the upper electrode layer 7 by heat curing at a predetermined temperature.

Thus, according to the circuit board with a capacitive element of the present invention, the semiconductor element 4 and other resistors are mounted and connected to the thin film circuit wiring 2 provided on the insulating substrate 1, and the lower electrodes of the thin film capacitive elements 3a and 3b are connected. If the layer 5 and the upper electrode layer 7 are connected to a predetermined thin film circuit wiring 2 or an electrode of the semiconductor element 5 directly or via a bonding wire 8, an electric circuit mounted in a communication device such as a mobile phone or satellite communication. It becomes the substrate.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention. For example, in the above-mentioned embodiments, the upper surface of the insulating substrate 1 can be changed. Although two thin film capacitive elements 3a and 3b are formed in the above, three or more thin film capacitive elements 3a and 3b may be provided.
a, 3b lower electrode layer 5, dielectric layer 6 and upper electrode layer 7
May be made of another material, and each thin film capacitive element 3
The lower electrode layers 5 of a and 3b may be formed of the same material as the thin film circuit wiring 2.

[0035]

According to the circuit board with a capacitive element of the present invention, since the circuit wiring and the capacitive element are formed by adopting the thin film forming technique on the insulating substrate, the line width and the adjacent space of the circuit wiring can be reduced. In addition, the shape of the capacitive element is small, and the entire device is small, so that it can be mounted on communication devices such as mobile phones, which are rapidly becoming smaller and lighter.

Further, according to the circuit board with a capacitive element of the present invention, the corner portion between the upper surface and the side surface of the lower electrode layer is formed between the dielectric layer and the upper electrode layer of the thin film capacitive element formed on the insulating substrate. Since the resin insulating material is interposed in the region facing the upper surface of the lower electrode layer, when the dielectric material is deposited on the upper surface and at least one side surface of the lower electrode layer by a thin film forming technique such as sputtering, Even if the upper electrode layer and the lower electrode layer are electrically short-circuited even if the corner portion is not covered with the dielectric substance with a predetermined thickness, the short circuit is effectively prevented by the resin insulator, and as a result, the thin-film capacitance element becomes a capacitive element. It is possible to exert a predetermined function as.

Furthermore, since the resin insulating material interposed between the dielectric layer and the upper electrode layer of the thin film capacitive element has a low dielectric constant, the capacitance value of the thin film capacitive element greatly varies due to the resin insulating material. Therefore, the capacitance value of the thin film capacitive element can be set to a predetermined value.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a circuit board with a capacitor according to the present invention.

FIG. 2 is an enlarged cross-sectional view for explaining the thin film capacitive element shown in FIG.

[Explanation of symbols]

 1 ... Insulating substrate 2 ... Thin film circuit wiring 3a, 3b ... Thin film capacitive element 5 ... Lower electrode layer 6 ... Tantalum oxynitride layer 7 ...・ ・ ・ ・ ・ Upper electrode layer 9 ・ ・ ・ Resin insulation

Claims (1)

[Claims] 1. A circuit board with a capacitive element, comprising a thin film circuit wiring and a thin film capacitive element formed on an insulating substrate, wherein the thin film capacitive element includes a lower electrode layer, an upper surface of the lower electrode layer, and at least one of the lower electrode layers. A dielectric layer deposited on the side surface and an upper electrode layer deposited on the surface of the dielectric layer, and between the dielectric layer and the upper electrode layer, the upper surface and the side surface of the lower electrode layer. A circuit board with a capacitor, wherein a resin insulator having a low dielectric constant is interposed in a region facing a corner portion of the.