JPH03116747A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To improve the yield of semiconductor devices and enable lowering the price by forming an adjusting element, at least one of the electrodes of which is open, and a bridge wiring across the adjusting element, pressurizing the bridge wiring based on the result of measurement of the electric characteristic, and making adjustment by contact with the open electrode of the adjusting element. CONSTITUTION:Surface circuits 2 formed on a compound semiconductor semi- insulating substrate 1 are connected with a bridge wiring 3 across an electrode also serving as a resistor and as a capacitor. The MMIC chip thus formed is packaged in a semiconductor case 4 and electrically connected thereto with bonding wires 5. For example the high-frequency electric characteristic of a gain is measured. If the desired electric characteristic is not obtained, the bridge wiring 3 is pressurized with a wedge and electrically connected to the electrode therebelow and the high-frequency electric characteristic is measured again. After it is confirmed that the desired characteristic is obtained, a cap 10 is put to complete a semiconductor device.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a semiconductor device, and particularly to a semiconductor device formed on a semi-insulating substrate made of a compound semiconductor such as gallium arsenide or indium phosphide (hereinafter referred to as GaAs or InP). The present invention relates to a method of manufacturing a semiconductor device using a microwave monolithic integrated circuit (hereinafter referred to as MMIC).

[Conventional technology]

An active element having a field effect transistor (hereinafter referred to as FET) structure is provided on a semi-insulating substrate made of a compound semiconductor, and the function of this active element is exhibited.

MMIC, which consists of a matching circuit using passive elements, has superior high-frequency characteristics compared to hybrid integrated circuits (hereinafter referred to as HIC), can be made smaller and cheaper, and has high reliability, so it is particularly popular in the several tens of GHz range. It is being put into practical use.

Conventionally, an MMIC consists of a thin metal film formed in close contact with the main surface of a semi-insulating substrate and an implanted layer in which, for example, Si ions are implanted into the semi-insulating substrate, and is further mounted in a semiconductor container made of, for example, ceramic. It was manufactured. This manufacturing method will be explained using figures.

FIGS. 4(a) to 4(f) are schematic cross-sectional views shown in order of steps to explain a conventional MMIC manufacturing method.

A photosensitive wave technique is applied to the main surface of a semi-insulating substrate 1 made of a compound semiconductor such as GaAs or InP shown in FIG.
A surface circuit 2 consisting of an FET or the like formed of a thin film metal having a multilayer structure of n and an implanted layer of Si ions is formed as shown in FIG. 4(b) to form an MMIC chip. As shown in FIG. 4(C), in this MMIC chip, the semiconductor container 4 is made of, for example, Au.
It is mounted by heating and melting the n-alloy. after that,
As shown in FIG. 4(d), the MMIC chip and the semiconductor container 4 are electrically connected by thermocompression bonding a bonding wire 5 made of, for example, a 30 μm Au wire. Furthermore, Fig. 4(e)
Cover the semiconductor container 4 with the cap 10 as shown in FIG. The characteristics of the assembled semiconductor devices are inspected by a detector 8 using a high-frequency signal from a signal source 7, and those that do not have the desired characteristics are rejected and only non-defective devices are manufactured.

[Problems to be Solved by the Invention] The conventional MMIC described above has no room for electrical adjustment, and defective products must be discarded in the final process, resulting in a reduction in yield due to the diffusion process for making MMIC chips. decided,
There is a drawback that variations in elements such as FETs cannot be corrected within the circuit.

In particular, for MMICs at several tens of GHz, FE
High performance at high frequencies is required for T, and its gate length Ag is also minute, such as 0.25 μm and gate-source distance 0.4 μm. Therefore, a variation in physical dimensions of 0.05 μm causes a variation in characteristics of 20% or more. At present, the controllability of gate length is 0.1 μm at a mass production pace. Therefore, although MMIC has high characteristic uniformity, there is high lot-to-lot variation in the diffusion process for making MMIC chips, and due to lot-out, hundreds of MMICs are produced.
It is not uncommon for MIC chips to be completely destroyed. This low yield is an impediment to lowering the price of semiconductor devices using MMICs, and although their superiority is acknowledged, it is also the cause of slowing down their widespread use.

[Means to solve the problem]

The method for manufacturing a semiconductor device of the present invention includes forming a microwave circuit consisting of a field effect transistor, a matching circuit using passive elements, and a conductor wiring including at least one bridge-like wiring on a semi-insulating substrate made of a compound semiconductor. A method for manufacturing a semiconductor device including the step of preparing a monolithic integrated circuit chip, the step of providing an adjustment element with at least one electrode in an open state at a predetermined position and the bridge-like wiring across the adjustment element; The method further includes an adjustment step of applying pressure to the bridge-like wiring to bring it into contact with the open electrode of the adjustment element based on the measurement results of the characteristics.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIGS. 1(a) to 1(h) are schematic cross-sectional views shown in order of steps to explain an embodiment of the present invention.
- For example, the thickness 11 of Ti-Pt-Au shown in Figure 1 (a)
Figure 1(b) shows a surface circuit 2 consisting of an FET, etc. formed of a thin film metal with a 00n multilayer structure and an implanted layer of Si ions.
It is formed like this. Further, the surface circuits 2 are connected to each other by a bridge wiring 3 called an air bridge, which is made of Au plating and has a width of 100 μm and a thickness of 2 μm, for example. As shown in Fig. 1(C), this bridge wiring is made of an electrode made of the previously mentioned Ti-Pt-Au thin film metal that has the function of a resistor and a capacitor.
For example, it has a structure spanning 100 μm x 100 μm).

The MM IC chip made in this way is shown in Figure 1 (
As shown in d), it is mounted in the semiconductor container 4 by heating and melting, for example, an AuSn alloy at 320°C. Thereafter, as shown in FIG. 1(e), the MMIC chip and the semiconductor container 4 are electrically bonded by thermocompression bonding, for example, a 30 μmφ Au bonding wire 5 at 280°C using a sapphire needle called a wedge. Connecting.

As shown in FIG. 1(f), the semiconductor device mounted with the MMIC chip manufactured in this way is connected to a high-frequency signal source 7 on the input side.
By supplying a signal from the semiconductor device through a coaxial cable 6 and connecting a detector 8 to the output side via the coaxial cable 6 to detect the signal output from this semiconductor device, high-frequency electrical characteristics such as gain can be measured and tested. do. At this time, if the desired electrical characteristics cannot be obtained, the bridge-like wiring 3, which was determined in advance at the time of development and design, is pressurized by a wedge, and the bridge-like wiring 3 is electrically connected to the electrode that it spans. After measuring and testing the high frequency electrical characteristics again and confirming the desired characteristics, a cap 10 is placed on the semiconductor device as shown in FIG. 1(b) to complete the manufacture of this semiconductor device.

FIG. 2 is a circuit diagram for explaining adjusting the input matching circuit using the present invention in, for example, a single-stage FET amplifier.

For example, a case will be explained in which the physical dimensions of the gate length 1g of FET II vary and the high frequency parameters specific to FET 11 vary.

The input circuit of FET11 consists of matching coil 1 connected in series.
It consists of a matching capacitor connected in parallel with 2. In advance, the matching coil 12 and the matching capacitor 13-1 are connected using the bridge-like wiring 3, and the bridge-like wiring 3 connects the open electrode of the matching capacitor 13-2, which is the adjustment element of part A. Take the internal layout of the MMIC chip. An electrical characteristic measurement test is performed on the semiconductor device in which this MMI C is mounted, and if the desired characteristics are not obtained, the bridge-like wiring 3 is crimped with pressure using a wedge, for example, to make the A part electrically conductive. By increasing the capacitance of the matching capacitor in the matching circuit, the mismatch is improved and desired characteristics are obtained.

FIG. 3 is a circuit diagram for explaining a modification of one embodiment of the present invention.

For example, in an amplifier with one stage of FET, the semi-insulating substrate 1
A method of adjusting the threshold voltage Vt of the FET 11 caused by variations in the implantation of Si ions for forming the active layer of the FET II formed on the main surface of the FET 11 will be described below. The potential of the gate terminal of FET11 is set by bias resistor 1.
4. Suppose that the threshold voltage of FET II in the design is, for example, Vt-1, OV, and in reality (
7) F E T 11 Teha V t = 0, 8
If it is V, the gate-source voltage must be reduced. In advance, a bias resistor 14-1 is inserted between the input terminal and the ground terminal and connected using the bridge-like wiring 3, and the bridge-like wiring 3 is connected to the open electrode of the bias resistor 14-2 for adjustment in part B. Take the internal layout of the MMIC chip that jumps over. The semiconductor device mounted with this MMIC is subjected to an electrical characteristic measurement test, and if the desired characteristics are not obtained, the bridge-like wiring 3 is crimped by pressure using a wedge, for example, to make the B part electrically conductive. Obtain optimal bias conditions by changing the bias resistance value.

Although examples of a matching capacitor and a bias resistor have been described above as adjustment elements, a matching coil can also be used as an adjustment element. By the way, FET for configuring MMIC
For example, the impedance that provides the lowest noise amplification and the impedance that provides the highest output generally do not match, and for example, the phase angle and absolute value of the S-parameter differ. According to the present invention, since the matching coil and the matching capacitor can be adjusted, it is possible to switch between the matching circuit constant for low noise amplification and the matching circuit constant for high output amplification, and one M
It is possible to select the characteristics using the MIC chip, and it is also possible to suitably meet the required performance.

〔Effect of the invention〕

As explained above, in the present invention, the bridge wiring 3 is formed across the adjustment element in the MMIC chip, and the electrical characteristics are measured and tested before the cap 10 is attached during the manufacturing process of the semiconductor device, and the desired electrical characteristics are obtained. In order to obtain the characteristics, the bridge-like wiring 3 is applied with a load and is crimped to the open electrode of the adjustment element to establish electrical continuity, which has the effect of improving the yield of semiconductor devices and reducing the cost. .

[Brief explanation of drawings]

FIGS. 1(a) to (h) are schematic cross-sectional views of an MMIC manufacturing method shown in order of steps to explain an embodiment of the present invention;
Figure 2 is a circuit diagram for explaining input matching circuit adjustment.
FIG. 3 is a circuit diagram for explaining bias circuit adjustment,
FIGS. 4(a) to 4(f) are schematic cross-sectional views shown in order of steps to explain a conventional MMIC manufacturing method. DESCRIPTION OF SYMBOLS 1... Semi-insulating substrate, 2... Surface circuit, 3... Bridge-like wiring, 4... Semiconductor container, 5... Bonding wire 6... Coaxial cable, 7... Signal source , 8・
...Detector, 9...Crimp part, 10...Cap, 1
1... FET, 12-1.12-2... Matching coil, 13... Matching capacitor, 14-1.14-2
...Bias resistance.

Claims (1)

[Claims] A step of preparing a microwave monolithic integrated circuit chip by forming a microwave circuit consisting of a field effect transistor, a matching circuit using passive elements, and a conductor wiring including at least one bridge-like wiring on a semi-insulating substrate made of a compound semiconductor. In a method for manufacturing a semiconductor device, the step of providing an adjustment element with at least one electrode open at a predetermined position and the bridge-like wiring across the adjustment element; A method for manufacturing a semiconductor device, comprising an adjustment step of pressurizing the wiring to bring it into contact with the open electrode of the adjustment element.