JPH10189724A - Manufacture of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a layer insulating film being excellent in flatness and insulation characteristics. SOLUTION: An MOS transistor is completed by forming a gate oxide film 2, a gate electrode 3 and a source-drain region 4 on an Si substrate 1. Then, a silicon oxide film 5 is formed on the whole surface of a device, an organic SOG film 6 is formed thereon and then boron ions are implanted into this SOG film 6, while an electron shower is cast thereon. By these processings, the organic SOG film 6 is modified, moisture and hydroxyl contained therein are lessened and the film is made to hardly absorb the moisture, while the organic SOG film 6 can be prevented from being charged positively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a technique for forming an interlayer insulating film on a device.

[0002]

2. Description of the Related Art In recent years, in order to further increase the degree of integration of semiconductor integrated circuits, it has been required to advance wiring miniaturization and multilayering. In order to multi-layer the wiring, an interlayer insulating film is provided between each wiring, but if the surface of the interlayer insulating film is not flat, a step is generated in the wiring formed on the upper part of the interlayer insulating film and a failure such as disconnection may occur. Is caused.

Therefore, the surface of the interlayer insulating film (that is, the surface of the device) must be as flat as possible. As described above, a technique for planarizing the surface of a device is called a planarization technique, and has become more and more important with miniaturization and multilayering of wiring. In the planarization technology, there is an SOG film as an interlayer insulating film that is frequently used. In particular, active study has been made on a planarization technology using a flow characteristic of an interlayer insulating film material.

[0004] SOG is a general term for a solution in which a silicon compound is dissolved in an organic solvent, and a film mainly composed of silicon dioxide formed from the solution. To form an SOG film, first, a solution in which a silicon compound is dissolved in an organic solvent is dropped on a substrate, and the substrate is rotated. Then, the film of the solution is formed thicker in the concave portion and thinner in the convex portion, so as to relieve the step on the substrate formed by the wiring. As a result, the surface of the coating of the solution is planarized.

[0005] Next, when heat treatment is performed, the organic solvent evaporates and the polymerization reaction proceeds to form an SOG film having a flat surface. As shown in the general formula (1), the SOG film has an inorganic S containing no organic component in the silicon compound.
There are an OG film and an organic SOG film containing an organic component in a silicon compound as represented by the general formula (2).

[SiO ₂ ] n (1) [R _X SiO _Y ] n (2) (n, X, Y: integers, R: alkyl group or aryl group) In addition to containing a large amount of hydroxyl groups, it is more fragile than a silicon oxide film formed by a CVD (Chemical Vapor Deposition) method, and when the film thickness is 0.5 μm or more, cracks tend to occur during heat treatment. is there.

On the other hand, in the organic SOG film, the occurrence of cracks in the heat treatment is suppressed, and the film thickness can be reduced to about 0.5 to 1 μm. Therefore, if an organic SOG film is used,
An interlayer insulating film having a large thickness can be obtained, and sufficient flattening can be performed even on a large step on the substrate. As described above, the inorganic SOG film and the organic SOG film have extremely excellent flatness. However, as described above, the inorganic SOG film contains a large amount of moisture and hydroxyl groups, and thus has an adverse effect on metal wiring and the like. May cause problems such as deterioration of electrical characteristics and corrosion.

[0008] Although the organic SOG film is less than the inorganic SOG film, the organic SOG film also has the same problem because it contains moisture and hydroxyl groups. Therefore, usually, when an SOG film is used as an interlayer insulating film, a silicon film formed by, for example, a plasma CVD method has a high insulating property and a high mechanical strength in addition to a property of relatively blocking moisture and a hydroxyl group. An insulating film such as an oxide film is interposed in the upper or lower layer of the SOG film (for example, see Japanese Patent Application Laid-Open No. 5-226334 (H01L21 / 3205)).

[0009]

In the prior art, the water resistance of the silicon oxide film itself formed by the plasma CVD method is better than that of the SOG film, but is not perfect. Just because it is provided, it is not enough to get the perfect water resistance. The present invention relates to a method for manufacturing a semiconductor device, and an object of the present invention is to obtain an interlayer insulating film having excellent flatness and insulating properties, and to enhance the reliability as a semiconductor device.

[0010]

According to a first aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising covering an element such as a transistor or a wiring formed on a semiconductor substrate with an insulating film, and applying a kinetic energy to the insulating film. And introducing an impurity into the electron shower when introducing the impurity.

According to a second aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising the steps of: forming an insulating film B on an element such as a transistor or a wiring formed on a semiconductor substrate;
Forming an insulating film C thereon, and introducing an impurity having kinetic energy and irradiating the insulating film C with an electron shower. Also,
The method of manufacturing a semiconductor device according to claim 3, wherein the insulating film B is formed on an element such as a transistor or a wiring formed on the semiconductor substrate.
Forming an insulating film C on the insulating film B; introducing an impurity having kinetic energy to the insulating film C and irradiating the insulating film C with an electron shower; Forming an insulating film D thereon.

In a fourth aspect of the present invention, the insulating film A or the insulating film C is made of an organic polymer such as an organic SOG. Claim 5
The method for manufacturing a semiconductor device according to
Is composed of inorganic SOG. In the method of manufacturing a semiconductor device according to a sixth aspect, the insulating film B is formed of a film having a lower hygroscopicity than the insulating film C.

According to a seventh aspect of the present invention, in the method of manufacturing a semiconductor device, the step of introducing the impurity having the kinetic energy is performed by ion implantation. Claim 8
In the method of manufacturing a semiconductor device, boron ions are used as the impurities. That is, by introducing impurities into the insulating films A and C such as an SOG film by a method such as ion implantation, the film is modified, so that moisture and hydroxyl groups contained in the film are reduced and the film is less likely to absorb water. .

When impurities such as ions are introduced into an insulating film such as an SOG film, the insulating film is positively charged due to the ion beam and secondary electrons emitted from the insulating film, and the electric field in this portion becomes high. Eventually, a large current may flow toward the substrate, destroying the insulating properties of devices under the insulating film, for example, a thin insulating film such as a gate insulating film. Therefore, even if the insulating film is positively charged, it can be neutralized.

In particular, since the SOG film is generally used to fill the recesses on the substrate and flatten the substrate surface, the SOG film is thicker than other insulating films and is formed over the entire surface of the substrate. Although the SOG film itself has a low dielectric constant, it tends to be positively charged when ion-implanted. However, such a problem can be solved by using an electron shower together.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A manufacturing method according to an embodiment of the present invention will be described with reference to FIGS. Step 1 (see FIG. 1A): A gate oxide film 2 (film thickness: 10) is formed on a (100) p-type (or n-type) single crystal silicon substrate 1.
nm) and a gate electrode 3 (thickness: 200 nm). Then, an n-type (or p-type) is formed on the substrate 1 by ion implantation using the gate oxide film 2 and the gate electrode 3 as a mask.
By doping the impurities, the source / drain regions 4 are formed in a self-aligned manner to complete the MOS transistor.

Further, after a silicon oxide film 21 is formed on the entire surface of the device by the CVD method, a contact hole 22 is formed in the silicon oxide film 21 on the source / drain region 4. Thereafter, an aluminum alloy film (Al-S) is formed on the entire surface of the device including the inside of the contact hole 22 by using a sputtering method.
i (1%)-Cu (0.5%)), and anisotropic etching is performed so that the aluminum alloy film has a desired pattern to form a source / drain electrode (source / drain wiring) 10. Form.

Step 2 (see FIG. 1B): A silicon oxide film 5 (film thickness:
(500 nm). The gases used in this plasma CVD method are monosilane and nitrous oxide (SiH ₄ + N _2).
O), monosilane and oxygen (SiH ₄ + O ₂ ), TEOS
(Tetra-ethoxy-silane) and oxygen (TEOS + O ₂ ), and the film formation temperature is 300 to 900 ° C.

Step 3 (see FIG. 1c): silicon oxide film 5
An organic SOG film 6 is formed on the substrate. The composition of the organic SOG film 6 is [CH ₃ Si (OH) ₃ ], and its thickness is 600 nm.
It is. First, an alcohol-based solution of a silicon compound having the above composition (for example, IPA + acetone)
Is dropped on the substrate 1 to rotate the substrate at a rotational speed of 2300 rpm.
For 20 seconds to form a coating of this solution on the substrate 1. At this time, the film of the alcohol-based solution is formed so as to be thicker in the concave portion and thinner in the convex portion than the step on the substrate 1 so as to reduce the step. As a result, the surface of the film of the alcohol-based solution is flattened.

Next, in a nitrogen atmosphere, 100 ° C. for 1 minute, 200 ° C. for 1 minute, 300 ° C. for 1 minute, 22 ° C.
For 1 minute and then at 300 ° C for 30 minutes.
As the alcohol system evaporates, the polymerization reaction proceeds and an organic SOG film having a flat surface and a thickness of 300 nm is formed. The organic SOG film 6 having a thickness of 600 nm is obtained by repeating this film formation-heat treatment operation once more.

Then, boron ions (B ⁺ ) are accelerated by ion implantation at an acceleration energy of 140 KeV and a dose of:
The organic SOG film 6 is doped under the condition of 1 × 10 ¹⁵ atoms / cm ² . As described above, by implanting ions into the organic SOG film 6, organic components in the film are decomposed, and moisture and hydroxyl groups contained in the film are reduced.

As a result, the organic SOG film 6 contains no organic components and contains only a small amount of water and hydroxyl groups.
Film (hereinafter referred to as a modified SOG film) 7. Further, simultaneously with the ion implantation, the substrate 1 (organic SOG film 6) is irradiated with an electron shower. FIG. 3 shows an electron shower irradiation device 50 used at this time. An electron shower device 52 is provided above the irradiation port 51, and a base 53 for mounting the substrate 1 is provided below the irradiation port 51. ing. Then, toward the substrate 1 on the base 53,
An ion beam from an ion implantation device (not shown) and an electron shower from an electron shower device 52 are irradiated toward the substrate 1, and the base 53 is simultaneously scanned left and right.

By irradiating the electron shower simultaneously with the ion implantation, the ion beam and the organic SOG film 6 are irradiated.
The organic SOG film 6 is prevented from being positively charged due to secondary electrons emitted from the SOG film. FIG. 4 shows a cross-sectional structure of a test device for confirming the effect of irradiating an electron shower during ion implantation into an organic SOG film.

L on an n-type (100) silicon substrate 55
After forming the element isolation region 56 by the OCOS method, a gate oxide film 57 having a thickness of 15 nm is grown in a wet atmosphere, and a polysilicon electrode 58 is formed thereon. Furthermore,
After the entire surface of the device is covered with a silicon oxide film 59 by a CVD method and an aluminum electrode wiring 60 connected to the polysilicon electrode 58 through a via hole is formed, the entire surface of the device is covered with an organic SOG film 61.

The test device is not one, but the area of the gate oxide film 57 is fixed at 20 × 20 μm ² , and the antenna ratio ((the area of the polysilicon electrode 58 + the area of the aluminum electrode wiring 60) / the area of the gate oxide film 57 Area) 1000-
A number of 16000 devices were used. In such a test device, if a certain voltage or current is continuously applied, dielectric breakdown occurs in the gate oxide film 57 after a certain time has elapsed. For example, the organic SOG film 61 is likely to be positively charged by ion implantation or the like. Due to this positive charge, the electric field in this portion increases, and finally a large current flows toward the substrate 55, and the insulating property of the gate oxide film 57 is reduced. Is destroyed. The time to this dielectric breakdown is a function of the electric field strength applied to the insulating film,
That is, TDDB (Time-Dependent Dielectric Brea
kdown).

The Qbd (the amount of charge flowing through the oxide film before the breakdown) is measured by the polysilicon electrode 58 and the aluminum wiring electrode 6.
50% from TDDB measurement with constant current stress applied to 0
The time to failure is calculated and calculated using the following equation. Qbd = ist × tbd Here, ist is the stress current, and tbd is the time until 50% destruction. The stress current was 10 mA / cm ²
And

FIG. 5 shows the relationship between Qbd and the antenna ratio in the test device shown in FIG. 4 when (1) no ion implantation is performed on the organic SOG film 61 (unimplanted: solid line in the figure), and (2)
When ions are implanted into the organic SOG film 61 (implanted (0 m
A): Fine dotted line in the figure), (3) Similar to the present embodiment, the case where the organic SOG film 61 is irradiated with an electron shower at the same time as the ion implantation (implanted (50 mA): Large dotted line in the figure and This is shown for each case of implanted (150 mA) (dotted line in the figure).

The numerical value in parentheses of implanted (mA) is a parameter for controlling the amount of supplied electrons with the emission current of the electron shower device 52. As is clear from FIG. 5, when ions are implanted into the organic SOG film 61,
As the antenna ratio increases, Qbd decreases (the life of the oxide film is shortened). On the other hand, when the electron shower is applied simultaneously with the ion implantation into the organic SOG film 61,
In substantially the same manner as in the case where the ion implantation is not performed on the organic SOG film 61, even if the antenna ratio changes, Qbd does not change and maintains a high value. This is due to the electron shower, organic SOG
This indicates that the positive charging of the film 61 is canceled.

As described above, in the present embodiment, the organic SOG
Even if an ion beam is irradiated for ion implantation into the film 6, the organic SOG film 6 (modified SOG film 7) is suppressed from being positively charged, and the gate oxide film 2 and the like under the film do not cause dielectric breakdown. Can be prevented. Step 4 (see FIG. 2A): A silicon oxide film 8 (thickness: 200 n) is formed on the modified SOG film 7 by using a plasma CVD method.
m). The conditions for forming the silicon oxide film 8 are the same as those for the silicon oxide film 5.

Step 5 (see FIG. 2B): Anisotropic etching is performed using a mixed gas of carbon tetrafluoride and hydrogen as an etching gas, and via holes are formed in the films 5, 7, and 8 on the source / drain regions 4. 9 is formed. Step 7 (see FIG. 2C): After cleaning the inside of the via hole 9 by sputter etching using an inert gas (for example, Ar), using magnetron sputtering,
In the via hole 9 and on the silicon oxide film 8, Al
An alloy film (Al-Si (1%)-Cu (0.5%)) (film thickness 500 nm), a Ti film (film thickness 50 nm), and a TiN film (film thickness 20 nm) are sequentially formed from below.

Then, the aluminum alloy film, the Ti film and the TiN film are patterned into a predetermined shape by applying a resist (not shown), exposing, and etching by a usual lithography technique and a dry etching technique (RIE method or the like). Then, the upper metal wiring 23 is formed. As described above, in the present embodiment, the interlayer insulating film 11 having a three-layer structure including the silicon oxide film 5, the modified SOG film 7, and the silicon oxide film 8 is formed on the MOS transistor. Accordingly, the thickness of the interlayer insulating film 11 can be increased, and sufficient flatness can be achieved even with a large step on the substrate 1.

Incidentally, the modified SOG is formed by each of the silicon oxide films 5 and 8.
The sandwich structure in which the film 7 is interposed is employed to further increase the insulating property and the mechanical strength of the interlayer insulating film 11 as a whole. Generally, plasma C
The silicon oxide film formed by the VD method itself is organic S
Although it has a lower hygroscopic property than the OG film and is excellent in water resistance, by implanting ions into this silicon oxide film, the hygroscopicity is slightly higher (still much lower than that of the organic SOG film). Although the moisture absorption of the silicon oxide film 5 becomes slightly higher, there is no problem because the modified SOG film 7 having low moisture absorption and excellent water resistance exists in the upper layer.
If the silicon oxide film 8 has a high hygroscopic property, the upper metal wiring 23 is adversely affected. Therefore, in the present embodiment, the formation of the silicon oxide film 8 after the ion implantation into the organic SOG film 6 prevents the hygroscopicity of the silicon oxide film 8 from increasing.

Since the modified SOG film 7 does not contain an organic component, the etching for forming the via hole 9 can be performed in an atmosphere of a mixed gas system of carbon tetrafluoride and hydrogen. Therefore, in this etching, even when a photoresist is used as an etching mask, the photoresist is not affected, and the modified SOG film 7 masked by the photoresist is not etched. Therefore, fine via holes 9 can be accurately formed.

Further, since the modified SOG film 7 contains no organic component, the etching rate of the modified SOG film 7 is the same as that of each of the silicon oxide films 5 and 8, and the photo-etching used as an etching mask The modified SOG film 7 does not shrink during the ashing process for removing the resist.
Therefore, cracks do not occur in the modified SOG film 7, and no recess occurs when the via holes 9 are formed. Therefore, the upper metal wiring 23 can be sufficiently buried in the via hole 9.

The modified SOG film 7 has excellent oxygen plasma resistance. FIG. 6 shows an index of oxygen plasma resistance, which is evaluated by focusing on the decrease in the thickness of the modified SOG film 7.
This shows the change in film thickness when the modified SOG film 7 formed by implanting argon ions into the organic SOG film 6 is exposed to oxygen plasma. The conditions of the ion implantation are as follows: acceleration energy: 140 KeV, dose: 1 × 10 ¹⁵ atoms
/ cm ² .

When the organic SOG film 6 is exposed to oxygen plasma (O ₂ plasma), the original organic SOG film 6 (No treatment)
The modified SOG film 7 was exposed to oxygen plasma while the film thickness was reduced by 16% as compared with the film thickness of O ₂ plasma aft (O ₂ plasma aft).
er Ar ⁺ impla.) and the thickness of the modified SOG film 7 (Ar ⁺ impla.) were not substantially reduced. However, the thickness of the modified SOG film 7 is 25% smaller than the thickness of the organic SOG film 6.

From the above results, it was found that the modified SOG film 7 was a film having excellent oxygen plasma resistance. Also,
It is considered that the film density is higher when the ion implantation is performed, since the film thickness is smaller when the ion implantation is performed than when the substrate is exposed to the oxygen plasma. Thus, the modified SO
Since the G film 7 is excellent in oxygen plasma resistance, for example, an oxygen-based gas can be contained as an etching gas for forming the via hole 9. When ashing the photoresist used as the mask, an oxygen-based gas with high ashing efficiency can be used.

The modified SOG film 7 contains no organic components, contains only a small amount of water and hydroxyl groups, and has no cracks even after the modification.
Either or both may be omitted. FIG. 7 shows that the organic SOG film 6 (untreated: unimplanted) and the modified SOG film 7 (ion implantation: Ar ⁺ -implanted) are each subjected to a heat treatment in a nitrogen atmosphere for 30 minutes, and subjected to a TDS method (Thermal D).
It shows the result of evaluation using absorption Spectroscopy). The ion implantation conditions were as follows: acceleration energy: 14
0 KeV, dose amount: 1 × 10 ¹⁵ atoms / cm ² .

This figure shows the amount of desorption with respect to H ₂ O (m / e = 18).
It can be seen that the modified SOG film 7 has little desorption with respect to H ₂ O (m / e = 18). This is achieved by implanting ions into the organic SOG 6 to form the modified SOG film 7.
This shows that the water and hydroxyl groups contained in the organic SOG film 6 decrease.

FIG. 8 shows an organic SOG film 6 and a modified SOG film 7.
Organic SOG film 6 (no treatmen)
t), the organic SOG film 6 exposed to oxygen plasma (O ₂ Pl
Asma) and the modified SOG film 7 (Ar ⁺ ) are left in the air in a clean room, and the results of evaluating the moisture in the film are shown. The amount of water in the film was determined by the FT-IR method (Fourier Transform
Using Infrared Spectroscopy), the area intensity of the absorption (around 3500 cm ⁻¹ ) of the O—H group in the infrared absorption spectrum was used as an index. The ion implantation conditions are acceleration energy:
140 KeV, dose amount: 1 × 10 ¹⁵ atoms / cm ² .

It can be seen that when exposed to oxygen plasma, not only the moisture before and after the treatment increased, but also the moisture increased one day later. On the other hand, not only does the modified SOG film 7 not increase after the ion implantation, but the increase in moisture is small compared to the organic SOG film 6 even when left in the air in a clean room. That is, it is understood that the modified SOG film 7 has lower hygroscopicity than the organic SOG film 6.

FIG. 9 shows a modified SOG film 7 and an organic SOG film 6.
The results of a pressure cooker test (PCT) (a humidification test, which was performed in a saturated steam atmosphere at 120 ° C. and 2 atm as a condition in the present embodiment) for the purpose of examining the moisture permeability of I have. Using the FT-IR method, the absorption peak (3
The area intensity (around 500 cm ^-1 ) was determined, and the relationship with the PCT time was plotted.

A sample (Ar ⁺ 20 KeV) having only the surface modified by ion implantation was prepared, and a sample having the entire film modified (Ar ⁺ 140 KeV) or a sample not modified (organic SOG) was prepared.
(Film 6: Untreatment), the following was found. (1) When the unmodified organic SOG film 6 is subjected to PCT, the absorption intensity around 3500 cm ^-1 (related to the OH group) shows a dramatic increase.

(2) In the modified SOG film 7, 3500 cm ^-1
The increase in absorption intensity around (with respect to the OH group) is small.
A sample in which only the film surface was modified is comparable to a sample in which the entire film has been modified. From the above results, it can be seen that a layer that suppresses moisture permeability can be formed by implanting ions.

FIGS. 10 to 14 show a silicon oxide film 8 on an NMOS transistor as shown in FIG.
The results of various experiments performed using a test device having an inter-layer insulating film composed of / organic SOG film 6 (modified SOG film 7) / silicon oxide film 5 are shown. The modified SOG film 7 is formed by implanting argon ions into the SOG film 6).

FIG. 10 shows the drain voltage dependence of the hot carrier lifetime (the time required for the Gm (transconductance) to degrade by a certain ratio, one of the parameters indicating the lifetime of the transistor) of the NMOS transistor. It can be seen that the hot carrier lifetime of the one using the modified SOG film 7 (especially, the one with the acceleration energy of 140 KeV) is extended by about two orders of magnitude compared to the one using the organic SOG film without ion implantation. .

FIGS. 11 and 12 show the threshold values Vt before and after the acceleration test (test in which a voltage of 5 V is continuously applied to the transistor of the test device at 200 ° C. for 2 hours). 11 shows the threshold value Vt before the acceleration test, and FIG. 12 shows the change amount of the threshold value Vt before and after the acceleration test. As shown in FIG. 11, before the acceleration test, the threshold value of the organic SOG film without ion implantation and that of the modified SOG film 7 hardly change.

However, as shown in FIG. 12, in the case of using an organic SOG film without ion implantation, the threshold value Vt greatly changed before and after the test, whereas the modified SOG
The one using the film 7 (especially, the acceleration energy is 140 KeV
), There is almost no change in the threshold value Vt regardless of the gate length. This result indicates that the threshold characteristics of the MOS transistor are stable for a long time.

FIG. 13 shows the amount of change in Gm of the transistor before and after the acceleration test similar to FIG. In the case of using an organic SOG film without ion implantation, the Gm greatly changed before and after the test, whereas the case in which the modified SOG film 7 was used (especially, the acceleration energy was 14
(At 0 KeV), there is almost no change in Gm regardless of the gate length. This result indicates that Gm of the MOS transistor is stable for a long time.

In FIGS. 10 to 13, the modified SOG
The improvement effect of the film 7 formed under the condition of the acceleration energy of 20 KeV is smaller than that of the film 7 formed under the condition of the acceleration energy of 140 KeV. This is shown in FIG.
As shown in 4, the acceleration energy (injection energy) is
There is a substantially positive correlation with the modification depth of the OG film, and it is considered that when the acceleration energy is 20 KeV, only the surface layer (about 50 nm) of the organic SOG film 6 has been modified.

As described above, in the present embodiment, the organic SOG
By introducing impurities into the film 6 by ion implantation, the film is modified, so that moisture and hydroxyl groups contained in the film are reduced and the film becomes difficult to absorb water, so that a highly reliable interlayer insulating film can be obtained. it can. Further, by irradiating an electron shower simultaneously with ion implantation, the organic SOG film 6 (modified SO
The G film 7) can be prevented from being positively charged, and an interlayer insulating film having excellent insulating properties can be obtained.

The present invention is not limited to the above embodiment, and the same effects can be obtained even if the present invention is carried out as follows. 1) Instead of the organic SOG film 6, polyimide or siloxane-knitted polyimide is used. These, including organic SOG films, are collectively referred to as organic polymers (or organic spin coating films).

2) Each of the silicon oxide films 5 and 8 is
Methods other than VD method (normal pressure CVD method, low pressure CVD method, EC
R plasma CVD method, photo-excitation CVD method, TEOS-CV
A silicon oxide film formed by a D method, a PVD method, or the like is used. In this case, gases used in the normal pressure CVD method are monosilane and oxygen (SiH ₄ + O ₂ ), and the film formation temperature is 400 ° C. or less. The gas used in the low pressure CVD method is monosilane and nitrous oxide (SiH ₄ + N ₂ O), and the film formation temperature is 900 ° C. or less.

3) Each of the silicon oxide films 5 and 8 is replaced with another insulating film (such as a silicon nitride film or a silicate glass film) having a high mechanical strength in addition to a property of blocking moisture and hydroxyl groups. The insulating film may be formed by any method such as a CVD method and a PVD method. 4) Use a conductive material other than aluminum (copper, gold, silver, silicide, refractory metal,
(Doped polysilicon, titanium nitride (TiN), alloy such as tungsten titanium (TiW)) and a laminated structure thereof.

5) The modified SOG film 7 is subjected to a heat treatment. In this case, dangling bonds in the modified SOG film 7 are reduced. Hygroscopicity is further reduced, and permeation of moisture is further reduced. 6) The composition of the organic SOG film 6 is replaced with the composition represented by the general formula (2). 7) The composition of the organic SOG film 6 is replaced with an inorganic SOG film represented by the general formula (1), and ions are implanted into the inorganic SOG film. In this case, moisture and hydroxyl groups contained in the inorganic SOG film can be reduced.

8) The modified SOG film 7 is also used as a passivation film. In this case, an excellent passivation film that can reliably protect the device mechanically and chemically can be obtained. 9) In the above embodiment, boron (boron) ions are used as ions to be implanted into the organic SOG film 6, but as a result, any ions that modify the organic SOG film 6 may be used.

Specifically, ions having a relatively small mass such as argon ion, boron ion and nitrogen ion are suitable, and among them, boron ion is most suitable.
In addition to these, the following ions can be expected to have a sufficient effect. Inert gas ions other than argon (helium ion, neon ion, krypton ion, xenon ion, radon ion). Since the inert gas does not react with the organic SOG film 6, there is no possibility that an adverse effect is caused by the ion implantation.

IIIb, IVb, Vb, VI other than boron and nitrogen
b, VIIb Elemental simple ions of each group and their compound ions. In particular, oxygen, aluminum, sulfur, chlorine, gallium,
Elemental ions of germanium, arsenic, selenium, bromine, antimony, iodine, indium, tin, tellurium, lead, bismuth and their compound ions. Among them, with respect to metal element ions, the dielectric constant of the organic SOG film 6 after the ion implantation can be suppressed low.

Group IVa and Va element simple ions and their compound ions. In particular, titanium, vanadium, niobium,
Elemental ions of hafnium and tantalum and their compound ions. Since the oxides of the IVa and Va group elements have a high dielectric constant, the dielectric constant of the organic SOG film 6 after ion implantation is also high. However, it is practically used except when an interlayer insulating film having a particularly low dielectric constant is required. No problem.

Each type of ion is used in combination.
In this case, a more excellent effect can be obtained by the synergistic action of each ion. 10) In the above embodiment, ions are implanted into the organic SOG film 6. However, the ions are not limited to ions, but may be atoms, molecules, or particles having kinetic energy (in the present invention, these are collectively referred to as impurities). ).

11) As a sputtering method, other than magnetron sputtering, a method such as diode sputtering, high-frequency sputtering, or quadrupole sputtering may be used. 12) As a method of sputter etching, besides using an inert gas, a reactive ion beam etching (RIBE, also called reactive ion milling) using a reactive gas (for example, CCl ₄ , SF ₆ ) may be used. .

13) The silicon oxide film 8 is omitted. 14) Although not shown in FIG. 2, to realize a further multilayer wiring structure, it is conceivable to form the modified SOG film 7 also on the upper metal wiring 23. Even in this case,
An electron shower is applied simultaneously with ion implantation for forming the modified SOG film 7.

[0063]

According to the present invention, the insulating film A or C such as an SOG film is modified by introducing impurities into the insulating film A or C by ion implantation or the like, so that the moisture or hydroxyl group contained in the film is modified. Is reduced and the film is less likely to absorb water, so that it is possible to prevent adverse effects on peripheral elements due to the moisture.

Further, by using the electron shower together, it is possible to prevent device characteristics from deteriorating due to positive charging of the insulating film. Therefore, an insulating film having excellent flatness and insulating characteristics can be obtained, and the reliability as a semiconductor device can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing a manufacturing process of a semiconductor device according to an embodiment of the invention.

FIG. 2 is a schematic cross-sectional view showing a manufacturing process of the semiconductor device according to the embodiment embodying the present invention;

FIG. 3 is a schematic view of an electron shower irradiation device according to the embodiment of the present invention.

FIG. 4 is a cross-sectional view of a test device for describing an embodiment of the present invention.

FIG. 5 is a characteristic diagram for explaining the embodiment of the present invention.

FIG. 6 is a characteristic diagram for explaining the embodiment of the present invention.

FIG. 7 is a characteristic diagram for explaining the embodiment of the present invention.

FIG. 8 is a characteristic diagram for explaining the embodiment of the present invention.

FIG. 9 is a characteristic diagram for explaining the embodiment of the present invention.

FIG. 10 is a characteristic diagram for explaining the embodiment of the present invention.

FIG. 11 is a characteristic diagram for explaining the embodiment of the present invention.

FIG. 12 is a characteristic diagram for explaining the embodiment of the present invention.

FIG. 13 is a characteristic diagram for explaining the embodiment of the present invention.

FIG. 14 is a characteristic diagram for explaining the embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 1 silicon substrate 5 silicon oxide film (insulating film B) 6 organic SOG film (organic polymer, insulating film A, insulating film C) 7 modified SOG film 8 silicon oxide film (insulating film D) 50 electron shower irradiation device

Claims (8)

[Claims] 1. An element such as a transistor or a wiring formed over a semiconductor substrate is covered with an insulating film A, and an impurity having kinetic energy is introduced into the insulating film A. A method of manufacturing a semiconductor device, comprising irradiating an electron shower. 2. a step of forming an insulating film B on an element such as a transistor or a wiring formed on a semiconductor substrate; a step of forming an insulating film C on the insulating film B; Introducing an impurity having kinetic energy and irradiating with an electron shower. 3. a step of forming an insulating film B on an element such as a transistor or a wiring formed on a semiconductor substrate; a step of forming an insulating film C on the insulating film B; A method of introducing an impurity having kinetic energy and irradiating an electron shower, and a step of forming an insulating film D on the insulating film C. 4. The insulating film A or the insulating film C is formed of an organic SO
4. The method for manufacturing a semiconductor device according to claim 1, comprising an organic polymer such as G. 5. The insulating film A or the insulating film C is made of an inorganic SO
The method of manufacturing a semiconductor device according to claim 1, wherein the semiconductor device is made of G. 5. 6. The insulating film B is made of a film having a lower hygroscopicity than the insulating film C.
13. The method for manufacturing a semiconductor device according to claim 1. 7. The method of manufacturing a semiconductor device according to claim 1, wherein the step of introducing the impurity having kinetic energy is performed by ion implantation. 8. The method of manufacturing a semiconductor device according to claim 1, wherein boron ions are used as said impurities.