JPS62104039A - Semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a semiconductor device which does not possibly accumulated heat improperly operate by providing protecting effect against alkali ion and moisture by a passivation film and forming it of an insulator having high thermal conductivity. CONSTITUTION:An insulating layer 26 of SiO2 is formed on the surface of a substrate 10 except electrodes 16, 18, a passivation film 28 is formed on the layer 26 and the electrodes 16, 18 to protect the surface of a semiconductor device. The film 28 is formed of aluminum nitride or gallium arsenide. Accordingly, the protecting effect against alkali ions and moisture are sufficient and the thermal conductivity of the aluminum nitride or the gallium nitride is large. Thus, even if the number of elements of the device can be increased in high density, it can prevent the device from heating to eliminate an improper operation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor device, and more particularly to a semiconductor device in which electrodes and the like are formed on a semiconductor substrate, and the surface is covered with an insulating passivation film.

A padding layer of an insulator is formed on the surface of a semiconductor device made of a silicon chip to protect the chip and electrodes from moisture, chemicals, and the like.

The S + 02 insulating film as a passivation film is
Also, the protective effect against Na ions is not sufficient.

Although the PSG film has a large protective effect against Na ions, it has poor moisture resistance and may cause corrosion defects in the AI electrode wiring due to water supply. Therefore, an insulating film of silicon nitride (S; 3N4), which hardly passes Na and other ions and has a higher protective effect against moisture than S + 02, is heated at 6θ0-900℃ using the plasma Cvn method. formed and used.

However, in semiconductor devices formed with such Si3-44 passivation films, due to the low thermal conductivity of Si3N4, as the number of device elements increases and device density increases, a lot of heat accumulates in the device, resulting in malfunction. There was a drawback that this occurred.

the purpose The present invention overcomes these drawbacks of the prior art.

An object of the present invention is to provide a semiconductor device that is free from heat accumulation and malfunction.

DISCLOSURE OF THE INVENTION According to the present invention, a semiconductor device in which an impurity-doped region, an electrode, an insulating layer, etc. are formed on one main surface of a semiconductor substrate, and these surfaces are covered with a padding film of an insulator, is a passivation film. It is made of an insulator that has a retaining effect on alkali ions and moisture and has high thermal conductivity.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of a semiconductor device according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 conceptually shows a cross-sectional structure of a semiconductor device constituting an FET.

In this example, two n÷ regions 12 and 14 are formed on one main surface of a p-type silicon substrate 10. n÷
Regions 12 and 14 each have an AI electrode 1B.

0 and n◆ regions 12 and 14 where 18 are in contact and formed
A gate electrode 22 is provided on the surface of the substrate between them with an insulating layer 20 of S r 02 interposed therebetween. The gate electrode 22 is 1
In this embodiment, it is made of polycrystalline silicon.

These two n◆ regions 12 and 14, the insulating layer 20, and the gate electrode 22 form a MOS transistor, that is, I(2FET). In this example, it is an n-channel conductivity type ICFET, and the n◆ region 12 serves as the source. , and the n◆ region 14 functions as a drain.The electrodes 18 and 18 connected to the n÷ regions 12 and 14 are respectively connected to other wiring perpendicular to the paper plane of FIG. Similarly connected to other wiring.

n◆region 12.14% of silicon substrate 10 gate electrode 2
2 is not formed with an insulating layer 24 of StO2.
is formed and has the function of isolating the ICFET from other elements disposed adjacent to it. Further electrodes 18 and 18
A 5in2 insulating layer 2B is formed on the other surface of the substrate 10, and passivation 1! I28 is formed to protect the surface of the semiconductor device. The passivation film 28 is made of aluminum nitride (AIM) or gallium nitride (Gap).
formed by.

According to this embodiment, the passivation@28 is formed of aluminum nitride or gallium nitride. Therefore, it has a sufficient protective effect against alkali ions and moisture, and at the same time, the thermal conductivity of aluminum nitride or gallium nitride is high. This can be prevented and malfunctions will not occur.

FIG. 2 conceptually shows an apparatus for forming the passivation film 28.

The illustrated apparatus is a capacitively coupled plasma Cvn reactor.A sample electrode 42 and a high-frequency electrode 44 are disposed facing each other in a quartz tube 40, and a pudge plate 28 is laminated on the sample electrode 42. Silicon chip l is jailed. A power source 4B that generates a high frequency is connected to the high frequency electrode 44, and the sample electrode 42 is grounded. Further, the sample electrode 42 is connected to a heating device t (not shown), and is provided so as to be able to heat the silicon chip 1 placed thereon to 250 to 380°C.

The gas supply port 48 is for supplying gas that is a raw material for forming the passivation film 28.

The vacuum exhaust port 50 is used to exhaust the gas inside the quartz tube 40 using a vacuum pump (not shown) to bring the inside of the quartz tube 40 into a reduced pressure state.

When forming the passivation film 28 using such an apparatus, first the passivation film 28 is formed on the electrode 42.
The silicon chip l on which is stacked, that is, the device shown in the first r14, in which the passivation film 2B is not formed, is @, M.

When forming the passivation film 28 of aluminum nitride on the silicon chip l, silane (SiH4), trimethylaluminum [AI(OH4)
)3] and ammonia gas (NH3).

Note that nitrogen gas (N) is used instead of ammonia gas (N)
N2), dinitrogen oxide (N20) or nitrogen dioxide (NO
□) may be supplied.

A vacuum pump (not shown) performs exhaustion from the vacuum exhaust port 50, and in this embodiment, the pressure inside the quartz tube 4θ is set to 1 orr. A high-frequency voltage is applied to the high-frequency electrode 44 to generate a high-frequency discharge, and the gas supplied into the quartz tube 4θ is turned into plasma, and aluminum nitride is passivated onto the heated silicon chip placed on the sample electrode 42. A film 28 is formed.

A passivation film with a thickness of about 1 pm is formed by performing high-frequency discharge for about 1 hour.

Note that the substrate on which the passivation film is formed may be a silicon substrate, gallium arsenide (GaAs), SOI, or any other suitable substrate.

In addition, when forming a passivation H28 of gallium nitride on the silicon chip 1, silane (SiH4), trimethylgallium Ha (CHt)3, etc. are supplied from the gas supply port 48.
1 and ammonia gas (N) f3). In this case as well, ammonia gas (NH3) is substituted with nitrogen gas (
N2), dinitrogen oxide (N20) or nitrogen dioxide (NO
2) may be supplied from the gas supply port 48.

Furthermore, in the same way as in the case of forming the aluminum nitride padding film 28, exhaust air is evacuated from the vacuum exhaust port 50 using a vacuum pump to bring the pressure inside the quartz tube 40 to Horr, and a high frequency voltage is applied to the high frequency electrode 44 to generate a high frequency discharge. Then, the gas supplied into the quartz tube 40 is turned into plasma, and a passivation film 28 of gallium nitride is formed on the silicon chip 1 placed on the sample electrode 42.

Further, in addition to the plasma CVD method described above, the passivation film 28 may be formed by a photo CVD method.

In this embodiment, a passivation film of FIT was explained, but the present invention can also be applied to passivation films of various other semiconductor devices.

Effects According to the present invention, since the padding layer film is formed of an insulator that has a protective effect against alkali ions and moisture and has high thermal conductivity, it has a blocking effect against alkali ions and moisture, and
Prevents heat from accumulating in the device, eliminating the risk of malfunction.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view conceptually showing a semiconductor device constituting an FIT to which the present invention is applied. FIG. 2 is a schematic diagram showing an example of an apparatus for forming a passivation film of a semiconductor device according to the present invention. Explanation of some marks 81. Silicon chip 10... Silicon substrate! 2,! 4. n◆Region 18.1B, Electrode 22, Gate electrode 2B, Passivation film 42, Sample electrode 44, High frequency electrode 4B, Power supply 48, Gas supply port 5G, Vacuum exhaust Patent applicant Fuji Photo Film Co., Ltd. Representative Katori Takao Maruyama

Claims (1)

[Claims] 1. A semiconductor device in which an impurity-doped region, an electrode, an insulating layer, etc. are formed on one main surface of a semiconductor substrate, and these surfaces are covered with an insulating passivation film, the device comprising: . A semiconductor device, wherein the passivation film is formed of an insulator that has a protective effect against alkali ions and moisture and has high thermal conductivity. 2. A semiconductor device according to claim 1, wherein the insulator contains aluminum nitride. 3. A semiconductor device according to claim 1, wherein the insulator contains gallium nitride.