JP3191352B2 - High frequency integrated circuit device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency integrated circuit device capable of adjusting the shape of a circuit for matching a load to a transmission line, for example.

[0002]

2. Description of the Related Art With an increase in demand for communication, there has been a demand for the development of devices used in such high-frequency circuits as the frequency of communication signals for microwave and millimeter wave bands increases. However, at higher frequencies than microwaves, it is necessary to match the load to the signal transmission line,
For example, when a low-noise amplifier is configured, if the input and output of the amplifying transistor are not matched, noise characteristics are significantly deteriorated.

[0003] The low-noise amplifier is composed of a hybrid IC. However, trimming of a matching circuit is performed by means such as cutting a wiring pattern or wire bonding in accordance with the variation in the characteristics of transistors used. That is the current situation.

However, in order to reduce or increase the operating frequency above the millimeter wave, or the chip size, but those that need to microwave monolithic IC form occurs, appropriate in such monolithic IC There is no means for post-adjustment of the matching circuit.

That is, in the case of a monolithic IC, the pattern of the matching circuit is fine, and the substrate is formed using a semiconductor material such as GaAs which is weak against heat and stress. For this reason, it is difficult to adopt a conventionally known trimming method, and the yield cannot be increased.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and can easily perform post-adjustment such as matching of a high-frequency transmission line and adjustment of a high-frequency circuit element.
It is an object of the present invention to provide a high-frequency integrated circuit device whose yield can be surely improved.

[0007]

In a high frequency integrated circuit device according to the present invention, an insulating film is formed on a substrate so as to be continuous with a circuit element such as a high frequency transmission line formed on the substrate. . Then, an adjustment circuit is required on the insulating film.
Element. In this case, the adjustment circuit element
Is electrically connected to the high-frequency circuit element,
The film is formed on the insulating film by vapor deposition and has a thickness of the high frequency
The thin film is thinner than the circuit element, and the insulating film is removed.
Is removed integrally with this insulating film.
It is.

[0008]

In the high-frequency integrated circuit device thus configured, the adjustment circuit element is integrally connected to the high-frequency circuit element when the insulating film is formed. If the insulating film is removed in such a state, the adjusting circuit element thereon is removed together with the insulating film, and the high-frequency circuit is trimmed. For example, when the insulating film is made of spin-on-glass, if this insulating film portion is dissolved with an organic solvent, the insulating circuit and the adjustment circuit element formed thereon are also removed, and the trimming of the high-frequency circuit is performed. Can be easily executed, and this can be easily applied to a monolithic IC or the like.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of a matching circuit based on series reactance of a high-frequency circuit formed on a GaAs substrate 11, for example, and a load 13 such as an input of an FET is connected to an end of a transmission line 12 as a high-frequency circuit element. It is connected.

[0010] A branch transmission line 14 having a length L2 that constitutes a part of a high-frequency circuit element is connected to a position of a length L1 from the load 13 of such a transmission line 12.
An adjustment transmission line (adjustment circuit element) 15 is formed at the distal end of the transmission line 14 so as to have a length L3 together with the branch transmission line 14. An insulating film 16 of spin-on-glass (SOG) is formed on the substrate 11 corresponding to the position of the adjustment transmission line 15, and the adjustment transmission line 15 is formed on the insulation film 16. Like that.

The transmission line 12, the branch transmission line 14, and the adjustment transmission line 15 are all formed of a thin film made of a low-resistance metal such as gold.
For example, a relatively thick wiring formed by electrolytic plating or the like is used. Further, the adjustment transmission line 15 formed on the insertion layer of the insulating film 16 is formed of a wiring having a relatively small thickness by means such as vapor deposition.

In the high-frequency matching circuit configured as described above, considering the matching method with reference to the branch point from the transmission line 12 of the branch transmission line 14 set to the distance L1 from the load 13, this branch The length L1 and the length L1 are set so that the value obtained by adding the impedance from the point to the branch transmission line 14 and the adjustment transmission line 15 and the impedance from the branch point to the load 13 is equal to the impedance from the transmission line 12 to the branch point. Set L3.
With such a setting, the transmission line 12 and the load 13 can be brought into a matching state.

The total length L3 of the branch transmission line 14 and the adjustment transmission line 15 and the length L1 from the branch point to the load 13
Is designed based on a method such as a circuit simulation.However, due to a deviation from a calculated value caused by a variation in a manufacturing process of a load 13 such as a transistor or a transmission line, an error due to a calculation method, and the like, Line 12 and load 13 are not in perfect alignment. Therefore,
In this state, signal reflection may occur at the junction between the transmission line 12 and the load 13, and the circuit characteristics may be degraded, thereby lowering the yield.

In the circuit device shown in the embodiment, by removing the insulating film 16 formed between the adjusting transmission line 15 and the substrate 11, the adjusting transmission line 15 on the insulating film 16 is removed. At the same time, the length of the branch transmission line 14 combined with the adjustment transmission line 15 is reduced from L3 to L2.

In the actual adjustment work, after the completion of this high-frequency circuit fabrication process, the circuit characteristics are measured and the branch transmission line is measured.
When it is determined that a better matching state is obtained when the length of the portion 14 is L2 than that of L3, and improvement in performance can be expected, the insulating film 16 is removed and the length of the portion of the branch transmission line 14 is reduced. L
Try to reduce from 3 to L2.

For example, in the case of a high-frequency circuit formed on a semiconductor substrate such as a GaAs substrate, if a characteristic measurement for determining whether or not to remove the adjustment transmission line 15 is performed in a wafer state, this wafer The adjustment of the elements on the entire surface can be performed collectively, and a great effect can be expected in shortening the adjustment process. Alternatively, each element may be divided and mounted from the state of the wafer, and then adjusted for each element.

Here, as the material of the insulating film 16 serving as the insertion layer, the aforementioned organic material insulating film such as SOG or resist is used. When such an insulating film 16 is formed, The insulating film 16 can be removed with an organic solvent. When the insulating film 16 is made of SOG and is not removed, it is heated and cured to securely hold the adjustment transmission line 15 thereon, thereby improving reliability.

If the insertion insulating film 16 is made of, for example, silicon oxide, the insulating film 16 can be removed by HF-based acid etching. That is, the insulating film
The insulating film 16 can be selectively removed by immersing the insulating film 16 in a solution that can be dissolved or etched in accordance with the material constituting the insulating film 16.

Here, in order to suppress the loss of the high-frequency transmission line, it is necessary to set the thickness of the wiring layers constituting the transmission lines 12 and 14 to a certain degree or more. It is effective that the transmission line 15 is configured to be thin enough to be easily removed together with the insulating film 16.

In the above embodiment, an example of a high-frequency transmission line has been described, but this can be applied to other high-frequency circuit elements. FIG. 2 shows an example in which the present invention is applied to an inductance element of a lumped constant circuit. A transmission line 20 and an adjustment transmission line 21 are formed in a spiral shape on a substrate. Then, an insulating film is formed as an insertion layer between the substrate under the spiral adjusting transmission line 21 and the substrate.
22 are formed.

In such a circuit element, the inductance changes depending on the number of turns of the transmission line 20 and the adjustment transmission line 21. However, when the characteristics are measured after the circuit is completed and the inductance is desired to be reduced, The insulating film 22 is removed together with the adjustment transmission line 21 in the same manner as in the above embodiment.

FIG. 3 shows an example in which the present invention is applied to an MIM type capacitive element. This capacitive element forms a lower transmission line 32 on a substrate 31,
An insulating film such as silicon nitride or silicon oxide is formed on the lower transmission line 32.
Form 33. Then, an upper transmission line is formed on the insulating film 33.
34 is formed so that a capacitance is set between the lower transmission line 32 and the lower transmission line 32.An insulating film 35 serving as an insertion layer and an adjustment transmission line 36 are further laminated on the insulating film 33. Formed. The adjustment transmission line 36 is formed so as to be connected to the upper layer transmission line 34.

In such a capacitive element, the capacitance is determined by the area where the lower transmission line 32 and the upper transmission line 34 and the adjustment transmission line 36 overlap. Then, when the characteristics are measured after the circuit fabrication is completed and the capacitance is to be adjusted to be small, the insulating film 35 may be removed together with the adjustment transmission line 36.

FIG. 4 shows an example in which the present invention is applied to a thin film resistor of a lumped constant circuit. A thin film resistor 41 and an adjusting thin film resistor 42 are formed on a substrate. The thin film resistor 41 is connected to the transmission line 431.
Connected between 432. An insulating film 44 is formed as an insertion layer between the adjustment thin-film resistor 42 and the substrate, and the resistance value is determined by the area of the thin-film resistor 41 and the adjustment thin-film resistor 42. Therefore, if the insulating film 41 is removed together with the adjusting thin film resistor 42 thereon, the resistance value is adjusted to be larger.

[0025]

As described above, according to the high-frequency integrated circuit device of the present invention, it is possible to easily adjust the trimming of a circuit element having a fine pattern after the circuit element is manufactured. Even in the case of being formed of a semiconductor material which is weak against heat and stress, it can be easily trimmed. Therefore, for example, post-adjustment of a matching circuit of a monolithic IC can be easily performed, and a large effect is exhibited in improving the yield of this type of semiconductor integrated circuit.

[Brief description of the drawings]

1A and 1B show a matching circuit according to an embodiment of the present invention, wherein FIG. 1A is a diagram showing a plane pattern, and FIG. 1B is a cross-sectional configuration diagram corresponding to line bb in FIG.

FIG. 2 is a diagram showing a plane pattern of a second embodiment applied to an inductance element of a lumped constant circuit.

FIGS. 3A and 3B show a third embodiment applied to an MIM type capacitor, in which FIG. 3A is a diagram showing a plane pattern thereof, and FIG. 3B is a cross-sectional configuration diagram corresponding to line bb in FIG.

FIG. 4 is a diagram showing a plane pattern of a fourth embodiment applied to a resistive thin film element of a lumped constant circuit.

[Explanation of symbols]

11, 31 ... board, 12, 21, 41 ... transmission line, 13 ... load, 14 ... branch transmission line, 15, 32 ... adjustment transmission line, 16, 23, 35, 44 ... insulating film.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yoshiki Ueno 1-1-1, Showa-cho, Kariya-shi, Aichi Japan Inside Denso Co., Ltd. (56) References JP-A-2-29002 (JP, A) JP-A-61- 248452 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01P 5/02 603

Claims (3)

(57) [Claims] And 1. A high-frequency circuit element of the thick film-like formed on the substrate, an insulating film formed on the substrate at a position continuous to the high-frequency circuit element in electrical contact prior SL RF circuitry As mentioned above,
Formed on the edge film by vapor deposition and having a film thickness of the high frequency
The thin film is thinner than the path element , and is required to be removed integrally with the insulating film by removing the insulating film.
High frequency integrated circuit device, characterized in that it comprises the element. 2. The insulating film is removed by dissolving in an organic solvent.
2. The high-frequency integrated circuit device according to claim 1, wherein the high-frequency integrated circuit device is made of an organic material . 3. The high-frequency circuit element is a thick-film branch transmission line formed by electrolytic plating, and the adjustment circuit element is a thin-film adjustment transmission line formed by vapor deposition. A high-frequency integrated circuit device according to claim 1.