JPS62206853A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To reduce contact resistance among a metallic layer in an opening section and upper and lower wiring layers, and to prevent an overetching to the lower-layer wiring layer or a semiconductor substrate when forming a side wall film by reacting the side wall film consisting of silicon and the like shaped to the side wall section of the opening section formed to an insulating film by the fluorine compound of a metal employed for burying the opening section. CONSTITUTION:Arsenic is implanted into a P-type silicon substrate 11, an N<+> diffusion layer wiring 12 is shaped through predetermined heat treatment, and an SiO2 film 14 is applied by using SiH4 and N2O at fixed pressure. An opening section is formed by employing a lithographic technique and a dry type etching technique, and a polycrystalline silicon film 15 is applied onto the whole surface of the substrate by using a decompression chemical vapor-phase deposition method. Polycrystalline silicon 15 is etched in an anisotropic manner through reactive ion etching employing a chlorine group gas such as BBr3-Cl2 to leave a side wall film 15a on the inner side wall of the opening section. Tungsten hexafluoride and argon are flowed at prescribed pressure and substrate temperature, and silicon in the side wall film 15a is replaced with a tungsten film 16. Tungsten hexafluoride is reduced, introducing hydrogen gas, and the tungsten film 16 is further grown.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention relates to a method for manufacturing a semiconductor device, and relates to a semiconductor device in which a metal layer such as tungsten is embedded in a wiring connection portion in a tower. Relating to a manufacturing method.

(Prior Art) Conventionally, in a semiconductor device, a method has been adopted in which a through hole is formed as a connection portion of δ to connect the upper and lower layers, and this through hole is filled with an iJl material such as tungsten. This method will be explained with reference to FIG.

In other words, the t or ? Silicon wiring layer Oj
B i 02 gQ, 3 is formed on top, and an opening (c), that is, a through hole is formed using ordinary photolithography and reactive ion etching (Fig. 4(a)).
. Thereafter, tungsten hexafluoride (WFa) is reacted with the silicon of silicon ygIC1υ in a reduced pressure CVD apparatus to grow tungsten [41] on the silicon 13QD (FIG. 4(b)). After silicon reacts with tungsten hexafluoride and the tungsten film 3 reaches a certain thickness, no reaction with silicon occurs, so tungsten hexafluoride R1! (24a).

According to this method, it is possible to selectively form tungsten m(2)1) on C>υ up to a thickness of about 0.5 μm, but if the thickness exceeds that, S
There was a problem in that on tOz 14 CJ3, tungsten pellet acid and subsequent growth were likely to occur, making it impossible to maintain monoselectivity.

In order to overcome this problem, Japanese Patent Application Laid-Open No. 58-932
There is a method of filling the opening in which tungsten is grown from the side wall of the opening in FIG. 4, which is disclosed in Japanese Patent No. 55. In other words, to explain in detail using diagram G5, first, as shown in Figure 5 (a), the t
Or? A silicon wiring layer is formed and an opening (
After that, a silicon film (c) is formed, and then silicon (g) is deposited by vapor phase growth or the like. Next, as shown in FIG. 5(b), the silicon film (c) is etched by reactive ion etching or the like, leaving the silicon film (25b) only on the side walls. Next, tungsten rsm was formed under reduced pressure using tungsten hexafluoride, as shown in Fig. 5(e).
Fill the opening (to) as shown. According to this method, it is possible to selectively form the tungsten layer (2), but the tungsten layer (2) and the underlying silicon wiring layer Qυ The contact resistance was increasing.

Furthermore, when leaving silicon # (25b) on the 8III wall, S
iO,gfl'l) on silicon J(
F) (2sa)) A technology that can meet these requirements is desired.

In addition, as shown in FIG. 5 (di), in the process of forming, for example, an aluminum (At) wiring II@ on the upper layer wiring and performing heat treatment,
The silicon film of the side wall portion and the lower silicon wiring layer QB
In this case, silicon reacts with aluminum and aluminum enters the silicon, forming an At-Si layer (c), which may cause a problem called "penetration". In this "penetration" part, the volume changes due to the temperature of the W substrate, creating a cavity, which has an adverse electrical effect.
This will happen. Also SiO! If the lower layer of the membrane is a PN junction, this junction will be destroyed.

(Intermediate Points to be Solved by the Invention) The present invention has been made in consideration of the above-mentioned problems, and is made by growing metal such as tungsten from the 111 wall of an opening such as a hole or a through hole. In a semiconductor device manufacturing method in which a buried metal layer such as tungsten is formed in an opening, the contact resistance between this metal layer and the upper and lower wiring layers or semiconductor substrate connected through this metal layer is reduced, and silicon The purpose of this invention is to prevent over-etching of the underlying wiring or the semiconductor substrate, which occurs when a semiconductor film such as the like is left only on the side wall portion by etching.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention forms an insulating film with openings on the semiconductor or metal surface so that this surface is exposed, and deposits the film by chemical vapor deposition. After a semiconductor film such as silicon is deposited on the opening and the insulating layer by a method, the semiconductor film is left on the sidewall of the opening by reactive ion etching to form a semiconductor sidewall film, and then chemical vapor deposition is performed. A semiconductor characterized in that a metal fluoride gas is introduced by a method, the fluoride gas is reacted with the semiconductor sidewall film, and then the opening is completely filled with metal by a chemical vapor deposition method. A method for manufacturing a device is provided.

(Function) According to the method of the present invention, a sidewall film of silicon or the like formed on the sidewall of an opening provided in an insulating film such as Sin is coated with a metal fluorine compound to fill the opening. By forming the sidewall film with a metal film having a low metal thickness through reaction, it is possible to prevent over-etching of the lower wiring layer or the semiconductor substrate when forming the sidewall film.

(Example) An example of the manufacturing method according to the present invention will be described with reference to FIG. First of all, Fig. 1 (as shown in al, Pucioo of 5Ωα
) Inject HX (As) into the silicon substrate u11 at 30KeV at a dose of 3xlOclP! After implantation, heat treatment was performed at 900°C for 40 minutes to form the N diffusion layer (wiring) 085.
．． After forming a 4 μm opening using lithography and dry etching techniques, a 0.1 μm polycrystalline silicon film (19) was deposited on the entire surface using a low pressure chemical vapor deposition method.
Deposit on a substrate at 00°C. After that, polycrystalline silicon (151) was anisotropically etched by reactive ion etching using a chlorine-based gas such as BBr or -C4, and the polycrystalline silicon (151) was etched as shown in FIG.
As shown in b), a polycrystalline silicon sidewall film (X
5a) remains. Next, when tungsten reacts with Gesten at a pressure of 0.2 Torr and a substrate temperature of 400°C, approximately 5
A tungsten film α0 of 0OA is formed (Fig. 1(C)
)). Subsequently, while introducing hydrogen (H3) gas, the tungsten hexafluoride is reduced with this hydrogen to further grow the tungsten film αe. Figure 1(d) shows hydrogen 1t/m
The cross-sectional shape of an embedded tungsten film formed by growing tungsten by chemical vapor deposition for about 20 minutes at a rate of 10 cc/min of tungsten hexafluoride, a pressure of 0.3'f'orr, and a substrate temperature of 400°C is shown below. It shows. In addition, as a result of forming an aluminum wiring in the upper layer using the tungsten embedded formed by this method and evaluating the contact characteristics, the contact resistance of the aluminum arrangement/m embedded tungsten was 3 × 10-'Ω-2 embedded tungsten/ The contact resistance of the N+ diffusion layer (As surface concentration 2X10cm) is 3~5X
10 Q-, showing good ohmic contact characteristics,
Even in the case of a diffused layer implanted with boron at 2×10 aR, the contact resistance of the buried tungsten wiring layer is 5 to 10×10
The score was 0-, which was good. This contact resistance value is, for example, the fourth
The value is 1150 to 1/100 compared to the conventional example shown in the figure.

Next, another embodiment of the present invention will be described using FIG. 2. Components common to those in FIG. 1 are designated by the same reference numerals. Figure 2 (
a) After forming the diffusion) fJ UJ in Figure 1(a),
After forming the tungsten hexafluoride (WFa) and argon film Qe (Fig. 2(b)),
), buried tungsten (lη) is formed.As a result of evaluating the contact characteristics at this time in the same way as in the previous example, the contact resistance of the buried tungsten/tungsten wiring layer is 2XlOΩ-, and the tungsten wiring M/N+ The contact resistance of the diffusion layer was 5 x 10-'Ωd, which again showed good ohmic contact characteristics.

Furthermore, in @2 figure (a) S i 01 H13' (
No overetching or penetration phenomenon of the lower layer was observed at all. Also, as shown in FIG. 3, in FIG. 2(C), the area under the tungsten wiring layer αJ is Sin! Membrane 081
It may be.

In any of the above embodiments, in the formation of the embedded tungsten u゛0 after forming the tungsten waist circumference, °
By controlling the speed of tungsten oil through the surface reaction, the embedded tungsten αη is more uniform and has no cavities.
can be formed, and reliability can be further improved.

The present invention is not limited to the above embodiments, and for example, the metal constituting the metal surface, that is, the wiring layer 03, may be made of titanium, zirconium, hafnium, niobium, tantalum, chromium, etc.
It may be molybdenum, tungsten, their silicides or nitrides, or nickel, palladium, platinum, their silicides, or metals whose main components are aluminum or copper; the metal constituting the fluoride may be molybdenum. good.

〔Effect of the invention〕

As described above, according to the present invention, openings such as contact holes or through holes of 0.5 μm or more can be completely filled with a metal layer such as tungsten. Good ohmic contact characteristics can be obtained between the two. Furthermore, by providing the first gold layer V4, it is possible to prevent the influence of over-etching to the bottom 1 m.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a manufacturing process of a semiconductor device according to an embodiment of the present invention, FIG. 2 is a sectional view showing a process of manufacturing a semiconductor device according to another embodiment of the invention, and FIG. FIGS. 4 and 5 are cross-sectional views for explaining a conventional manufacturing method. 11...Silicon substrate, 12...1 diffusion layer, 13.
...Tungsten film, 14.=SiO, II, 15,
158...Silicon film, 16...Tungsten film,
17...Embedded tungsten, 18...8i0! I
I. Applicant: Director of the Agency of Industrial Science and Technology Tatsu Todoroki

-1f5DL Figure 2 Figure 3 Figure 4

Claims (5)

[Claims] (1) After forming an insulating film with an opening on the semiconductor or metal surface so that this surface is exposed, and depositing a semiconductor film on the opening and the insulating film by chemical vapor deposition. , a semiconductor film is left on the side wall of the opening by reactive ion etching to form a semiconductor side wall film, and then a metal fluoride gas is introduced by chemical vapor deposition, and this fluoride gas reacts with the semiconductor side wall film. After that, the opening portion is completely filled with metal by a chemical vapor deposition method. (2) The metal that constitutes the metal surface is titanium, zirconium, hafnium, niobium, tantalum, chromium, molybdenum, tungsten, and their silicides or nitrides, or nickel, palladium, platinum, and their silicides, or aluminum, copper. 2. The method of manufacturing a semiconductor device according to claim 1, wherein the semiconductor device is any metal whose main component is. (3) The method for manufacturing a semiconductor device according to claim 1, wherein the metal constituting the fluoride is tungsten or molybdenum. (4) The method of manufacturing a semiconductor device according to claim 1, wherein the metal deposition rate by chemical vapor deposition using fluoride is determined by the surface reaction rate. (5) Claim 1 that the semiconductor film is a silicon film
A method for manufacturing a semiconductor device according to section 1.