JPS62274641A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To prevent direct contact of a BPSG film with a substrate and an interconnection layer including a contact part, by covering the lower layer of the BPSG film as a smooth coating film with an underlay film, and covering the upper layer by an insulating film other than said BPSG film. CONSTITUTION:On a silicon semiconductor substrate 1, a first underlay oxide film 2, a PSG film 3 as a second underlay insulating film and a BPSG film 4 as a smooth coating film are sequentially formed. An opening 7a, which has a slightly larger size, is provided by an anisotropic etching in the parts of the surface of the BPSG film 4 and the PSG film 3. Then, by the reflow treatment of the BPSG film 4, the surface side facing the opening 7a is made to be the gentle curved surface. After an SOG film 5 is applied and formed thereon, an opening is provided at specified dimensions in the SOG film 5, the BPSG film 4, the PSG film 3 and the underlay oxide film 2 by anisotropic etching. Thus a contact hole 7 is formed. In this way, the BPSG film 4 as the smooth coating film is completely covered with the lower PSG film 3 and the upper SOG film 5.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a semiconductor device and a method for manufacturing the same, and more particularly relates to an improvement in a means for forming a contact hole structure in a semiconductor device. It is something.

[Conventional technology]

Conventionally, it has been formed in semiconductor devices.

The so-called smooth coat film is generally made of PSG (P
An insulating film made of phospho-silicate-glass is used. This PSG film has alkali metal gettering and blocking functions,
Furthermore, it has excellent properties as a smooth coat film, such as having no adverse effects on silicon substrates or wiring materials.On the other hand, there is currently a growing demand for higher speeds and smaller sizes in semiconductor devices. As the temperature increases, it becomes necessary to make the bond shallower, and BPJG (Boro-phaspho-sil) is used to reduce the temperature in the reflow process.
The introduction of icate-g 1ass) membranes is progressing.

For your reference, FIG. 6 shows a schematic cross-sectional structure of a contact portion in a conventional semiconductor device having a smooth coat film made of this type of BPSGH.

That is, in the contact hole structure according to the conventional example shown in FIG. 6, first, as is well known, CVD (
C: Chemical-Vapour-Deposit
The BPSG film 4 as the smooth coat film described above is formed on the underlying oxide film 2 of the silicon semiconductor substrate 1 using a chemical vapor deposition method (on, chemical vapor deposition method), and then the contact hole 7 is formed by anisotropic etching or the like. Open the
Further, after that, a reflow process is performed to properly shape the opening of the contact hole 7, and then a wiring layer such as A-Si is formed by sputtering or the like (not shown).

That is, in this case, PS is used as the smooth coat film.
The reason why the BPSG film is more suitable for speeding up and miniaturizing the device configuration than the G film is that the temperature in the reflow process can be lowered, and therefore the junction depth can be kept shallow.

[Problem that the invention seeks to solve]

However, on the other hand, in the structure of the contact hole 7 made of the smooth coat film using BPSGI]I4,
During the reflow process, as seen in the part 6 shown in FIG. Boron, phosphorus, etc. in the i-film 4 are diffused into the substrate l and into the silicon deposited on the contact, and as a result, on the one hand, there is an inconvenience that an ohmic failure occurs in the contact part. On the other hand, BPS is used for wiring layers such as Au-5i.
Since the G film 4 is in contact, boron and phosphorus are also present in the wiring layer.

There were undesirable problems such as silicon and the like being diffused and precipitated in the contact area.

This invention was made to solve these conventional problems, and its purpose is to
In a semiconductor device using a smooth coat film made of SG, BPSGIljJ is a silicon substrate.

Also, the wiring layer including the contact portion was prevented from being directly touched. An object of the present invention is to obtain a semiconductor device of this type and a method for manufacturing the same.

[Means for solving problems]

In order to achieve the above object, a semiconductor device and a method for manufacturing the same according to the present invention are provided using BP as a smooth coat film.
The lower layer of the SG film is covered with an underlay film, and the upper layer is covered with an insulating film other than the BPSG film.

[For production]

That is, in the present invention, the lower layer of the smooth coat film made of the BPSG film is coated with an underlayer film, and the upper layer is coated with an insulating film other than the BPSG film, and the inside of the silicon substrate from the BPSG film and the wiring layer including the contact portion are coated. By avoiding the diffusion and precipitation of boron, phosphorus, silicon, etc. in the BPSG II, poor connection at the contact area can be improved and low-temperature reflow is possible.
This makes it possible to fully utilize the features of the smooth coat film.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of a semiconductor device and a method for manufacturing the same according to the present invention will be described in detail below with reference to FIGS. 1 to 5.

FIG. 1 is a schematic sectional view showing a contact portion of a semiconductor device having a smooth coat film made of a BPSG film to which an embodiment of the present invention is applied. The same reference numerals indicate the same or equivalent parts.

In the apparatus of the embodiment shown in FIG. 1, prior to the formation of the BPSG film 4, a second underlay insulating film 31, for example, the above-mentioned PSG film, is formed on the underlay oxide film 2, and this underlay insulating film 3 is After forming the BPSG film 4, the upper layer including the portion in contact with the contact hole 7 is covered with an insulating film 59, for example, a 5OG (Spin-on-Glass) film.

Here, the SOG film refers to a silicon oxide film formed by a so-called spin coating method, in which a solution of silicon dioxide (Si02) dissolved in an organic solvent is dropped onto a substrate and the substrate is spun. ing.

FIGS. 2(a) to 2d) outline the manufacturing process flow in the configuration of the embodiment shown in FIG. 1.

That is, first, on the silicon semiconductor substrate 1, a first underlying oxide film 2. The second underlying insulating film, shown here is BPSG as a smooth coat film with PSGSaO2.
After sequentially forming the films 4, this BPSGljJ4. Then, a part of the PSGSaO2 surface is selectively opened lower a with a slightly thicker dimension ((a) in the same figure), and then the surface side facing the open lower a is subjected to reflow treatment of the BPSG film 4. After forming the SOG film 5 into a gently curved surface (FIG. 5(b)) and coating the SOG film 5 thereon (FIG. 2(C)), the SOG film 5 is further etched by anisotropic etching. BPSG film 4. PSGSaO2 is then selectively opened in the underlying oxide film 2 to the desired dimensions to form contact holes 7 (
Figure (d)).

Therefore, in the device of the embodiment shown in FIG. 1 obtained in this way, the smooth coat film BPSGIIQ4 is completely covered with the SOG film 5 of the underlying PSGSaO2 layer, and as a result, this! In this case, a contact structure with a good shape can be obtained by low-temperature processing similar to the conventional method.

In addition, FIGS. 3(a) to 3(e) show an outline of the manufacturing process flow according to another embodiment, and the configuration of this embodiment in FIG. 3 is similar to the configuration of the embodiment in FIG. This is a case where the BPSG film 4 as a smooth coat film is completely covered, but only the underlying oxide film 2 is used as the lower layer.

That is, first, a BPSG film 4 as a smooth coat film is formed on the underlying oxide film 2 of the silicon substrate l, and a part of its surface is anisotropically etched.
The lower opening a is selectively opened to a slightly larger dimension, but at this time, the corresponding portion of the underlying oxide film 2 is also lost (FIG. 4(a)). Then, when reflow is applied, the above B
Since there is a possibility that the PSG film 4 may come into contact with the substrate 1 due to sagging, the opening in the underlying oxide film 2 may be removed. In the same figure (b), an oxide film is again formed on the contact area.
)), the surface facing the open lower a is made into a gently curved surface by reflow treatment (Figure (C)), and the SOG film 5 is coated thereon (Figure (D)). , further by anisotropic etching, these 5OGIIQ 5
, BPSG■4. Then, contact holes 7 are formed by selectively opening the underlying oxide film 2 according to the desired dimensions (FIG. 4(e)).

Therefore, also in the case of the device according to the embodiment shown in FIG.
The contact structure is completely covered with the upper layer SOG film 5, and a contact structure with a good shape can be obtained by low-temperature processing similar to the conventional method.

Note that the lower layer film of the BPSGI Mo4 is a C nitride film, plasma nitride film, or other oxide film instead of the PSG film.
In place of the SOG film, a CvD insulating film such as a nitride film, plasma nitride film, or other oxide film may be used as the upper layer film, and the same action and effect can be achieved. 4 and 5 show schematic cross-sectional structures of an embodiment and a modified device in which a CvD insulating film is used as the upper layer film, respectively. It is also possible to form a multilayer film and an upper film.

〔Effect of the invention〕

As detailed above, according to the present invention, phosphorus glass lfi (BP) containing boron is used as the smooth coat film.
In a contact hole structure for a semiconductor device using a BPSG film (SG film), a contact hole is opened while the BPSG film is completely covered with a lower insulating film and an upper insulating film, and this BPSG film is used as a semiconductor substrate.

In this type of device configuration, boron, phosphorus, silicon, etc. can be transferred from the BPSG film to the substrate part and the wiring part, since it is prevented from directly touching the wiring connection part through the contact hole and the wiring layer. It has excellent features such as being able to obtain a good contact structure through low-temperature treatment that is favorable for the device configuration while eliminating or suppressing the effects of precipitation, and also being relatively simple in structure and easy to implement. It is something that you have.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing a contact hole portion of a semiconductor device having a smooth coat film made of a BPSG film to which an embodiment of the present invention is applied, and FIGS. 2(a) to d) are the embodiments shown in FIG. FIGS. 3(a) to 3(e) are schematic sectional views showing an overview of the manufacturing process flow of the device, and FIGS. FIG. 5 is a schematic cross-sectional view showing a contact hole portion of a semiconductor device according to still another embodiment and a modified example, and FIG. 6 is a schematic cross-sectional view showing a contact hole portion of the same semiconductor device according to a conventional example. 1... Silicon semiconductor substrate, 2... Underlay oxide film, 3... BPSGII5I lower layer film (underlay film)
, 4... BPSG film (phosphorus glass film containing boron) as a smooth coat film, 5... Upper layer film of the BPSG film, 7... Contact hole opening. Figure 1 1: Silicon is also tanran Mari Kankyu ((Tsume Roa 2 Gojinso/〃Pauiri p. 5: BPSG Moon Flame-'' Jumping over Nino, 7: Ko〉/Kutonel and Opening Diagram 2 (a) a (b) (C) (d) Fig. 3 7a Fig. 4 ° Fig. 5 Fig. 6

Claims (6)

[Claims] (1) In a contact hole structure of a semiconductor device using a phosphorus glass film (BPSG film) containing boron as a smooth coat film, the BPSG film is covered with a lower layer insulating film and an upper layer insulating film, and this BPSG film is used as a semiconductor substrate, A semiconductor device characterized in that a wiring connection portion through a contact hole and a wiring layer are not directly touched. (2) The semiconductor device according to claim 1, wherein the lower layer insulating film is an insulating film such as a phosphorus glass film (PSG film), a nitride film, a plasma nitride film, or an oxide film. (3) According to claim 1 or 2, the upper insulating film is an insulating film such as a silicon oxide film formed by spin coating, a nitride film, a plasma nitride film, or an oxide film formed by chemical vapor deposition. The semiconductor device described. (4) In the contact hole structure of a semiconductor device using a phosphorous glass film (BPSG film) containing boron as a smooth coat film, the underlying oxide film of the semiconductor substrate is used as the lower insulating film, and the oxide film is used as a lower layer insulating film directly on the underlying oxide film or as a layer as required. A BPSG film is formed through the lower insulating film of No. 2, and this BPS
A step of selectively opening a part of the surface of the G film or the second lower layer insulating film to a slightly larger size;
a step of reflowing the film, a step of forming an upper insulating film thereon, each of the upper insulating films, the BPSG film or the second lower insulating film, and the portion of the lower insulating film corresponding to the opening, A step of forming a contact hole by selectively opening the contact hole according to the desired dimensions, and preventing the BPSG film from directly touching the semiconductor substrate, the wiring connection portion through the contact hole, and the wiring layer. A method for manufacturing a semiconductor device, characterized in that: (5) The second lower layer insulating film is a phosphorus glass film (PSG film)
, or an insulating film such as a nitride film, a plasma nitride film, or an oxide film. (6) Claim 4 or 5, wherein the upper insulating film is an insulating film such as a silicon oxide film formed by a spin coating method, a nitride film formed by a chemical vapor deposition method, a plasma nitride film, or an oxide film. A method of manufacturing the semiconductor device described above.