JPH11274410A - Semiconductor device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To give such a protective film structure to a semiconductor device that the characteristics of a protective film do not fluctuate even when the film is heat-treated. SOLUTION: An npn transistor Q1 is formed by using a semiconductor substrate 1. A silicon oxide film 9 is arranged on the substrate 1, and a thin film resistor 13 for laser trimming is arranged on the film 9. In addition, wiring 16 is arranged on the silicon oxide film 9 for connecting the resistor 13 to the transistor Q1. At least, the trimmed spot of the thin film resistor 13 for laser trimming is covered in such a state that the spot is brought into contact with the silicon oxide film 23 and the transistor Q1 is covered in such a state that the transistor Q1 is brought into contact with a silicon nitride film 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a semiconductor device having a thin film resistor for laser trimming on a semiconductor substrate, and more particularly to a protective film structure.

[0002]

2. Description of the Related Art FIGS. 26 and 27 show an example of a semiconductor device having a thin film resistor 72 for laser trimming. The npn transistor Q2 is formed using the silicon substrate 70. Further, a silicon oxide film 71 is formed on the silicon substrate 70, and a thin film resistor 72 is disposed thereon. This thin film resistor 72 is connected to a wiring (electrode) 73 by npn.
It is electrically connected to the transistor Q2. further,
The thin film resistor 72 and the wiring 73 are covered with a protective film (passivation film) 74.

At the time of heat treatment (aluminum sintering, plasma damage recovery annealing) in the wafer process, a reducing atmosphere (for example, 10%) is used in order to suppress an increase in the interface state between the silicon substrate 70 and the oxide film 71. H ₂ /
Normally, heat treatment is performed at N ₂ ). However, some heat treatments in the assembly process after the completion of the wafer process cannot be performed in a hydrogen atmosphere. For example, in glass sealing of ceramic packages, etc.
Sealing in an oxidizing atmosphere, or surface oxidation in an oxidizing atmosphere and sealing in an inert atmosphere are required for the purpose of ensuring leakiness between glass and ceramic. Also in vacuum sealing and the like, baking in vacuum is performed for the purpose of outgassing from a can package or a chip adhesive.
In heat treatments other than these reducing atmospheres, Si / Si
Since the interface state of O ₂ increases and the balance and constant of the circuit are different from those at the time of adjustment, the characteristics of the circuit (transistor Q2) fluctuate.

[0004]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a semiconductor device having a protective film structure whose characteristics do not change even after heat treatment, and a method of manufacturing the same.

[0005]

The present inventors have examined various protective film structures and found that a silicon nitride film (SiN film) is strong against a change in characteristics after heat treatment. This is because H (hydrogen) included in the silicon nitride film during heat treatment
Is diffused to produce an effect equivalent to performing heat treatment in a reducing atmosphere. However, in a device that performs laser trimming, the silicon nitride film is not suitable for a single protective film, and the silicon nitride film is sublimable during resistance melting by laser, so that the internal pressure increases and film cracks occur. To solve this, see FIGS.
As a protective film 74 shown in FIG. 7, a lower silicon oxide film 75a
And upper SiN / using upper silicon nitride film 75b.
A structure in which the lower layer is SiO ₂ is effective. However,
In our test, the upper SiN / lower Si
The two-layer protective film structure of O ₂ causes a characteristic change due to heat treatment. This is considered to be due to the fact that hydrogen is consumed in SiO ₂ due to the existence of the SiO ₂ film 75a between the SiN film 75b, which is a hydrogen supply source, and the silicon substrate 70.

That is, the protective film 74 is formed of an upper SiN / lower S
Laser trimming can be performed favorably by using the two-layer structure of iO _2. However, when heat treatment at 300 ° C. or more and 550 ° C. or less is performed in the assembling process after the completion of the wafer manufacturing process, the characteristics of the transistor Q2 may fluctuate. Will happen. Note that heat treatment at 550 ° C. or higher is not usually performed because melting of the wiring (electrode) formed of aluminum occurs.

Therefore, a semiconductor device according to claim 1 is
The laser trimming thin film resistor is characterized in that at least a trimming portion is covered in contact with a silicon oxide film and at least a semiconductor element is covered in contact with a silicon nitride film.

Therefore, the trimming portion is covered in contact with the silicon oxide film, and when the thin film resistor is melted by the laser, the silicon oxide film is melted and solidified again, and no film crack occurs. In addition, the semiconductor element that is likely to have characteristic fluctuations is covered with the silicon nitride film in a state of being in contact with the silicon nitride film, and the characteristics do not change even if a heat treatment at 300 ° C. or more is performed.

In a method of manufacturing a semiconductor device, an insulating film is disposed on a semiconductor substrate, and a thin film resistor for laser trimming having a predetermined shape is disposed on the insulating film. . Then, wiring for connecting the semiconductor element formed using the semiconductor substrate and the thin film resistor for laser trimming is arranged on the insulating film. Further, a silicon nitride film is deposited on the wiring, and a trimming portion in the laser trimming thin film resistor is opened in the silicon nitride film. Subsequently, a silicon oxide film is deposited on the silicon nitride film, and a trimming portion of the thin film resistor for laser trimming is covered with the silicon oxide film.

Thus, the semiconductor device according to the first aspect can be manufactured. Here, a silicon nitride film is deposited on an insulating film from a state where a wiring is left on the thin film resistor for laser trimming, and the laser trimming is performed on the silicon nitride film. Opening at least a trimming portion of the thin film resistor for use, further removing at least the trimming portion of the thin film resistor in the wiring exposed at the opening of the silicon nitride film, and thereafter, forming a silicon oxide film on the silicon nitride film. When deposited, it is practically preferable.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view of a semiconductor device according to this embodiment. FIG. 2 is a sectional view taken along the line AA of FIG. In FIG. 1, the silicon oxide film 23 of FIG. 2 is omitted for easy viewing.

As shown in FIG. 2, an n-type epitaxial layer 3 is formed on a p-type silicon substrate 2 in a semiconductor substrate 1. An element isolation p-type region 5 is formed in the n-type epitaxial layer 3, and an adjacent element is insulated and isolated by the p-type region 5. An n-type buried layer 4 is formed between the silicon substrate 2 and the epitaxial layer 3 in the isolated epitaxial layer 3. Also,
A p-type base region 6 is formed in a surface portion of the n-type epitaxial layer 3, an n-type emitter region 7 is formed inside the p-type region 6, and a surface layer of the n-type epitaxial layer 3 is further formed. An n-type collector region 8 is formed in the portion.

On the upper surface of the semiconductor substrate 1, a silicon oxide film 9 as an insulating film is formed. Contact holes 10, 11, 12 are provided in predetermined regions of silicon oxide film 9.
Are formed.

In a predetermined region on the upper surface of the silicon oxide film 9, a thin film resistor 13 for laser trimming made of a CrSi film is formed. The thin film resistor 13 for laser trimming has a rectangular shape as shown in FIG.
Both ends of the upper surface of the laser trimming thin film resistor (CrSi film) 13 are provided with a TiW film 14 as a barrier.
a and 14b are formed. That is, the TiW film 14
Reference numerals a and b function as barrier metals for preventing alloying of the aluminum wirings (electrodes) 19 and 20 and the CrSi film 13 described later.

Further, on the silicon oxide film 9, an aluminum wiring (electrode) 16 made of an aluminum thin film is arranged. More specifically, in FIG. 2, an aluminum wiring (electrode) 17 electrically connected to the n-type emitter region 7 through the contact hole 10, an aluminum wiring (electrode) 18 electrically connected to the p-type base region 6 through the contact hole 11,
Aluminum wiring (electrode) 19 for electrically connecting n-type collector region 8 and one end of thin film resistor 13 for laser trimming through contact hole 12, aluminum for electrically connecting the other end of thin film resistor 13 for laser trimming It has a wiring (electrode) 20.

In this manner, np
An n transistor Q1 is formed. And this n
The pn transistor Q1 and the thin film resistor 13 are covered with the following protective film.

Plasma CVD is performed on the aluminum wiring 16.
Forming a silicon nitride film (P-SiN film) 21
I have. That is, the silicon nitride film (SiN film) 21
iH _Four(Silane) and NH_Three(Ammonia) and the plasma
Deposited by decomposition and reaction by CVD equipment
You. The predetermined region 22 in the silicon nitride film 21 is
It is open. This opening 22 is thin for laser trimming.
This includes the trimming portion Z1 of the film resistor 13 and
In the example, it is slightly wider than the trimming location Z1. Sa
Further, the silicon nitride film 21 including the opening 22 is
Silicon oxide film (SiO_TwoMembrane) 23
Are formed. Here, in this example, the silicon nitride film
21 has a thickness of 1 μm and a silicon oxide film 2
3 has a thickness of 0.2 μm.

As described above, at least the trimming portion Z1 of the laser trimming thin film resistor 13 is covered with the silicon oxide film 23 so as to be in contact therewith, and at least the npn transistor Q1 (region Z2) is in contact with the silicon nitride film 21. Covered. Here, the silicon nitride film 21 has a weak adhesion to silicon, but the silicon nitride film 21 is in contact with the silicon substrate (1) via the silicon oxide film (SiO ₂ ) 23 having a high adhesion, and thus has a high adhesion. Power can be secured.

Although the sputtered SiO ₂ is used as the silicon oxide film 23, another oxide film (for example, CVD-SiO 2
₂ ) You can. Then, from this state, the laser trimming thin film resistor (CrSi film) 13 is laser-trimmed. At this time, the protective film does not crack. That is, C
While the SiN film is in contact with the rSi film 13, the CrSi
When the laser trimming of the film 13 is performed, the CrSi film 13 is melted.
Evaporates at the contact point with Si, there is no place to go for stress,
The film cracks. On the other hand, in this example, the CrSi film 1
3, a silicon oxide film (SiO ₂ ) 23 is disposed, and the SiO ₂ is melted without sublimation and solidified again.
No film cracking occurs.

After the completion of the wafer process including the laser trimming, the process is shifted to an assembling process. This step includes a heat treatment. That is, for example, in glass sealing of a ceramic package, sealing in an oxidizing atmosphere, or surface oxidation in an oxidizing atmosphere and sealing in an inert atmosphere are performed. In vacuum sealing or the like, baking in a vacuum is performed. In the present example, the characteristics of the npn transistor Q1 do not fluctuate in a heat treatment other than such a reducing atmosphere. This is because H (hydrogen) included in the silicon nitride film (SiN) 21 during the heat treatment
Is diffused to produce an effect equivalent to performing heat treatment in a reducing atmosphere. That is, the SiN film 21 is deposited by decomposing and reacting SiH ₄ (silane) and NH ₃ (ammonia) by the plasma CVD apparatus. At this time, if H decomposed from SiH ₄ is present in the film. Conceivable.

Next, a method of manufacturing the semiconductor device will be described with reference to FIG.
This will be described with reference to FIG. 3, 5, 7, and 9 are plan views corresponding to FIG. 1, and FIGS. 4, 6, 8, and 10 are cross-sectional views corresponding to FIG.

First, as shown in FIGS. 3 and 4, a semiconductor substrate 1 on which a p-type silicon substrate 2, an n-type epitaxial layer 3, an n-type buried layer 4, and a p-type region 5 for element isolation are formed is prepared. Then, a p-type base region 6, an n-type emitter region 7, and an n-type collector region 8 are formed in the n-type epitaxial layer 3. Further, a silicon oxide film 9 is deposited on the upper surface of the substrate 1.

Then, on the silicon oxide film 9, a thin film resistor (CrSi film) 13 for laser trimming and TiW
The film 14 is deposited, and the films 13 and 14 are formed into a desired shape by thin-film photoetching. Thereby, a rectangular two-layer structure of TiW / CrSi is formed. Furthermore, the contact holes 10, 11, and 12 are formed by removing the silicon oxide film 9 at desired positions by contact photoetching to prepare for contact with the aluminum wiring (electrode).

Subsequently, as shown in FIGS. 5 and 6, an aluminum thin film 16 is formed on the entire surface by sputtering, and the aluminum thin film 16 is photo-etched to form aluminum wirings (electrodes) 17 to 20 of a desired shape. At this time, the aluminum thin film 16 on the thin film resistor 13 for laser trimming and the TiW film 14 is left. After that, the resist for removing aluminum is removed.

Then, as shown in FIGS. 7 and 8, a silicon nitride film (P-SiN film) 21 is deposited on the entire surface by plasma CVD, and photo-etched to form a silicon nitride film 2.
An opening 22 is formed in 1 (a window is opened). During this etching, in the thin film resistor 13 for laser trimming, the aluminum thin film 16 serves as an etching stopper, and the TiW film 14
The silicon nitride film (P-SiN film) 21 can be etched without damaging the thin film resistor (CrSi film) 13. In this step, an opening is also formed in a pad portion where wire bonding is performed at the time of assembly.

Further, as shown in FIGS. 9 and 10, a patterned resist 24 is disposed. From this state, the aluminum thin film 16 is etched using the resist 24 as a mask, and the aluminum thin film 16 functioning as an etching stopper is removed as shown in FIGS. At this time,
The resistance value of the thin film resistor 13 for laser trimming is determined by the length L1 of the aluminum thin film 16 to be removed. Also,
At the time of this etching, the portions other than the thin film resistor 13 for laser trimming are protected by the resist 24 shown in FIGS. Following the removal of the aluminum thin film 16, the TiW film 14 is removed using the resist 24 as a mask. Then, resist 24
Is removed. Then, as shown in FIGS. 1 and 2, a silicon oxide film (SiO ₂ ) 23 is deposited by sputtering or CVD to be a protective film of the thin film resistor 13 for laser trimming. As a result, the trimming portion Z1 in the laser trimming thin film resistor 13 is covered with the silicon oxide film 23.

Further, an unnecessary region of the silicon oxide film 23, that is, a window for a pad portion for performing wire bonding in a later assembling step is opened. Note that the silicon oxide film 23 other than the opening 22 may be removed. Then, passivation annealing is performed.

Thereafter, laser trimming of the laser trimming thin film resistor 13 and assembling after completion of such a wafer process are performed. Although only the npn transistor Q1 is shown as a semiconductor element in FIGS. 1 and 2, a large number of other elements are formed on the substrate 1, and some of the elements include a thin film resistor that does not perform laser trimming. It is connected. The protective film structure of the thin film resistor without performing the laser trimming has a two-layer structure of the upper silicon oxide film 23 and the lower silicon nitride film 21.

Hereinafter, a silicon nitride film (SiN film) 21
An experiment was conducted on the effect of suppressing the characteristic fluctuations caused by the above. Heat treatment (380 ° C., 30 minutes, N ₂ ) was performed on the semiconductor device adopting the structure shown in FIGS.
That is, the npn of the SiN / CVD-SiO ₂ protective film structure
Heat treatment (380
° C., 30 minutes, was N _2).

The npn before and after the heat treatment in this case is
The base current and the collector current with respect to the base voltage of the transistor were measured. The result is shown in FIG. FIG.
1, the horizontal axis represents the base voltage, and the vertical axis represents the base current and the collector current.

FIG. 12 shows the current amplification factor hFE (= IC / IB) of the npn transistor obtained from the result. In FIG. 12, the horizontal axis represents the collector current, and the vertical axis represents the current amplification factor hFE.

From FIGS. 11 and 12, the heat treatment (380
(30 ° C., 30 minutes, N ₂ ), the base current IB in the low current region increases and the current amplification factor hFE decreases. This indicates that the recombination current is increasing, and is considered to be caused by electrons injected from the emitter into the base being trapped by the interface states on the base surface.

On the other hand, a semiconductor device employing the structure shown in FIGS.
The same heat treatment (380 ° C, 30 minutes,
N_Two) Was done. That is, the sputtered SiO_Two/ SiN protection
Semiconductor device incorporating npn transistor with protective film structure
Heat treatment (380 ° C, 30 minutes, N _Two) Was done.

FIG. 13 shows that n before and after the heat treatment in this case.
The measurement results of the base current and the collector current with respect to the base voltage of the pn transistor are shown. The current amplification factor hFE of the npn transistor obtained from the result (= IC / IB)
Is shown in FIG. From FIGS. 13 and 14, the heat treatment (3
It can be seen that the base current IB in the low current region does not increase and the current amplification factor hFE does not decrease even at 80 ° C., 30 minutes, N ₂ ).

Generally, the interface state is considered to be a dangling bond at the Si / SiO ₂ interface, and it is considered that hydrogen is effective as a terminator. 12 to 1
From Fig. 4, it is considered that the SiN film functioned as a hydrogen supply source during the heat treatment.

As described above, this embodiment has the following features. (A) As shown in FIGS. 1 and 2, as a protective film structure of the laser trimming thin film resistor 13 and the npn transistor Q1, at least a trimming portion Z1 of the laser trimming thin film resistor 13 is covered with a silicon oxide film 23 in contact therewith. At the same time, at least the npn transistor Q1 (region Z2) was covered with the silicon nitride film 21 in contact therewith. Therefore, the trimming portion Z1 is covered in contact with the silicon oxide film 23, and when the thin film resistor 13 is melted by the laser, the silicon oxide film 23 is melted and solidified again, so that no film crack occurs. Further, there is a concern that characteristic fluctuations may occur.
pn transistor Q1 (region Z2) is silicon nitride film 2
The characteristics are not changed even if heat treatment at 300 ° C. or more is performed while being covered in a contact state at 1.

That is, the SiN film 21 is used as a protective film for the region Z2 where the characteristic variation is concerned, and the protective film is formed of a single layer of SiO ₂ so that the laser trimming thin film resistor 13 can perform good laser trimming. By doing
The SiO ₂ film is good for melting and re-solidifying together during resistance melting by laser. As described above, even if a heat treatment of 300 ° C. or more is applied, a protective film structure in which characteristics do not change can be obtained. (B) As a manufacturing method, as shown in FIGS. 3 and 4, a silicon oxide film 9 is disposed on the semiconductor substrate 1, and a thin film resistor 13 for laser trimming having a predetermined shape is disposed on the silicon oxide film 9. . Then, as shown in FIGS. 5 and 6, np formed on the silicon oxide film 9 by using the substrate 1 is formed.
n transistor Q1 and thin film resistor 13 for laser trimming
And an aluminum thin film (wiring) 16 for connecting to the substrate. Further, as shown in FIGS. 7 and 8, a silicon nitride film 21 is deposited on the silicon oxide film 9, and at least a trimming portion Z1 in the laser trimming thin film resistor 13 is opened in the silicon nitride film 21. Subsequently, as shown in FIGS. 1 and 2, a silicon oxide film 23 is deposited on the silicon nitride film 21, and a trimming portion Z 1 in the thin film resistor 13 for laser trimming is changed to the silicon oxide film 2.
Covered with 3.

In this manner, the semiconductor device (a) can be manufactured. That is, by forming a protective film structure of SiO ₂ / SiN other than the thin film resistor 13 for laser trimming and forming a window in the SiN protective film 21 only for the thin film resistor 13 for laser trimming, a single SiO ₂ protective film structure can be obtained. (C) In this manufacturing method, an aluminum thin film (wiring) 1 is formed on the thin film resistor 13 for laser trimming as shown in FIGS.
6 while depositing a silicon nitride film 21 on the silicon oxide film 9 and
9, at least a trimming portion Z1 in the thin film resistor 13 for laser trimming is opened.
Aluminum thin film (wiring) 1 exposed in opening 22 of silicon nitride film 21 as shown in FIGS.
In FIG. 6, at least the trimming portion Z1 of the thin film resistor is removed, and then a silicon oxide film 23 is deposited on the silicon nitride film 21, which is practically preferable. That is, when the window of the silicon nitride film 21 is opened, the aluminum thin film 16 functions as an etching stopper.
Film 14 and thin film resistor for laser trimming (CrSi film) 1
3 is protected. (Second Embodiment) Next, a second embodiment will be described with reference to the first embodiment.
The following description focuses on the differences from this embodiment.

In this embodiment, an SOI substrate is used. Hereinafter, the manufacturing method will be described. First, as shown in FIG.
An SOI substrate 30 is prepared. This SOI substrate 30 has an n-type single-crystal silicon layer 33 disposed on a single-crystal silicon substrate 31 with a silicon oxide film 32 interposed therebetween. This is because, for example, after a silicon oxide film 32 is formed on a p-type single-crystal silicon substrate 31 and an n-type single-crystal silicon substrate (33) are subjected to a predetermined treatment, the temperature is about 1100 ° C. The single crystal silicon substrate (33) is bonded and polished to a required thickness. Then, a trench 34 is formed in a predetermined region of the silicon layer 33 using dry etching or the like, and the trench 3 is formed.
An oxide film 35 is formed on the side surface of the trench 4 and the trench 3 is formed.
4 is buried with polysilicon 36. This allows
Adjacent elements are insulated and separated by the oxide film 35 and the trench 34.

Then, as shown in FIG. 16, an oxidation resistant mask 37 is formed in a predetermined region on the surface of the silicon layer 33. The oxidation-resistant mask 37 is formed by depositing a nitride film (SiN) using a vapor phase growth method such as CVD and patterning it by a photolithography process.

Further, as shown in FIG.
A selective oxide film 38 is formed on the surface of the silicon layer 33 by oxidation. This selective oxide film 38 is for separating adjacent elements or semiconductor regions on the surface of the substrate.
Further, n is formed in the element formation region of the substrate (silicon layer 33).
A p-type base region 39, an n-type emitter region 40, and an n-type collector region 41 for forming a pn bipolar transistor are formed.

Subsequently, as shown in FIG.
An insulating film 42 is deposited thereon. The insulating film 42 is made of a BPSG film, an SOG film, or the like. Further, as shown in FIG.
A thin film resistor 43 for laser trimming is formed on the insulating film 42. This thin-film resistor 43 is made of CrSi by sputtering or the like.
A film is deposited and patterned into a desired shape.

Then, as shown in FIG.
After a contact hole is formed, an electrode wiring material such as aluminum is deposited and patterned to form a desired wiring 44. In FIG. 20, the thin film resistor 43 is connected to the collector region 41 of the transistor. After that, a silicon nitride film 45 as a protective film is deposited on the substrate 1.

Subsequently, as shown in FIG. 21, an opening 46 is formed in the laser trimming region of the silicon nitride film 45.
To form Then, as shown in FIG. 22, a silicon oxide film 47 is deposited thereon.

The semiconductor device formed as described above is subjected to laser trimming of the thin film resistor 43 to adjust the resistance value. After completion of such a wafer process, assembling involving heat treatment is performed.

In addition to those described above, the present invention may be implemented as follows. As shown in FIG. 23 instead of FIG. 2, a silicon nitride film 50
To deposit SiN on the trimming portion of the thin film resistor 13.
/ SiO ₂ structure. In this case, the presence of the silicon nitride film 50 results in, for example, excellent moisture resistance at the trimming portion in a specification in a molded state.

In addition to the structure shown in FIGS.
As shown in FIGS. 4 and 25, only the trimming portion Z1 may be used as the silicon oxide film 23 directly covering the thin film resistor 13. That is, only the trimming portion Z1 may be covered by the silicon oxide film 23 in contact therewith.

Further, an npn transistor Q1 is assumed as a semiconductor element formed using the substrate 1,
It may be a p-transistor, a MOS transistor other than a bipolar transistor, or an element other than a transistor.

[Brief description of the drawings]

FIG. 1 is a plan view of a semiconductor device according to a first embodiment.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a plan view of the semiconductor device for illustrating a manufacturing process.

FIG. 4 is a cross-sectional view of the semiconductor device for illustrating a manufacturing process.

FIG. 5 is a plan view of the semiconductor device for illustrating a manufacturing process.

FIG. 6 is a cross-sectional view of the semiconductor device for illustrating a manufacturing process.

FIG. 7 is a plan view of the semiconductor device for illustrating a manufacturing process.

FIG. 8 is a cross-sectional view of the semiconductor device for illustrating a manufacturing process.

FIG. 9 is a plan view of the semiconductor device for illustrating a manufacturing process.

FIG. 10 is a cross-sectional view of the semiconductor device for illustrating a manufacturing process.

FIG. 11 illustrates characteristics of an npn transistor.

FIG. 12 illustrates characteristics of an npn transistor.

FIG. 13 illustrates characteristics of an npn transistor.

FIG. 14 is a graph showing characteristics of an npn transistor.

FIG. 15 is a cross-sectional view of the semiconductor device for describing a manufacturing process of the semiconductor device according to the second embodiment.

FIG. 16 is a cross-sectional view for explaining a manufacturing process of the semiconductor device.

FIG. 17 is a cross-sectional view for explaining a manufacturing process of the semiconductor device.

FIG. 18 is a cross-sectional view for explaining a manufacturing process of the semiconductor device.

FIG. 19 is a cross-sectional view for explaining the manufacturing process of the semiconductor device;

FIG. 20 is a cross-sectional view for explaining the manufacturing process of the semiconductor device;

FIG. 21 is a cross-sectional view for explaining a manufacturing process of the semiconductor device.

FIG. 22 is a cross-sectional view for explaining a manufacturing process of the semiconductor device;

FIG. 23 is a cross-sectional view of another example of a semiconductor device.

FIG. 24 is a plan view of another example of a semiconductor device.

FIG. 25 is a sectional view taken along line BB of FIG. 24;

FIG. 26 is a plan view of a semiconductor device.

FIG. 27 is a sectional view taken along line XX of FIG. 26;

[Explanation of symbols]

Reference Signs List 1: silicon substrate, 9: silicon oxide film, 13: thin film resistor for laser trimming, 16: aluminum wiring, 21: silicon nitride film, 23: silicon oxide film, Q1: npn transistor

Claims (3)

[Claims] An insulating film disposed on a semiconductor substrate; a thin film resistor for laser trimming disposed on the insulating film; and an insulating film disposed on the insulating film and formed using the semiconductor substrate. A wiring for connecting a semiconductor element and the laser trimming thin-film resistor, comprising: a silicon oxide film covering at least a trimming portion of the laser trimming thin-film resistor, and at least the semiconductor A semiconductor device, wherein the element is covered with a silicon nitride film in contact therewith. 2. A step of arranging an insulating film on a semiconductor substrate and arranging a thin film resistor for laser trimming of a predetermined shape on the insulating film; and using the semiconductor substrate on the insulating film. Arranging wiring for connecting the formed semiconductor element and the laser trimming thin film resistor; and depositing a silicon nitride film on the insulating film;
Opening at least a trimming portion of the laser trimming thin film resistor with respect to the silicon nitride film; and depositing a silicon oxide film on the silicon nitride film and forming a trimming portion of the laser trimming thin film resistor with a silicon oxide film. A method of manufacturing a semiconductor device, comprising: a step of covering. 3. A method for depositing a silicon nitride film on an insulating film from a state in which wiring is left on the thin film resistor for laser trimming, and at least trimming the silicon nitride film in the thin film resistor for laser trimming. And removing at least a trimmed portion of the thin film resistor in the wiring exposed at the opening of the silicon nitride film, and thereafter depositing a silicon oxide film on the silicon nitride film. 3. The method for manufacturing a semiconductor device according to item 2.