JP2944159B2 - Method for manufacturing semiconductor device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a semiconductor device capable of preventing an increase in wiring resistance of polycrystalline silicon in a contact hole.

(Prior Art) A method of manufacturing a semiconductor device for improving a contact portion of an internal wiring of an integrated circuit is disclosed in Japanese Patent Application Laid-Open No. 64-42818.

In the case of this publication, an N-type or P-type
After forming the type diffusion layer, deposited on this diffusion layer, BP
A contact hole is formed in an interlayer insulating film containing a low-melting silicate glass containing at least 1 × 10 ^-21 cm ^-3 of each element, and the same as the lower diffusion layer of the contact hole at the bottom of the contact hole and inside the interlayer insulating film. Conduction-type ion implantation is performed, and the activation heat treatment is performed to planarize the surface of the interlayer insulating film, thereby forming a taper on the inner peripheral upper edge in the contact hole, thereby improving the step coverage of the contact wiring. It is like that.

FIG. 2 is a process sectional view showing another conventional method for manufacturing a semiconductor device. First, as shown in FIG. 2A, a thermal oxide film 22 is formed on a silicon substrate 21 to a thickness of about 0.02 to 0.05 μm.

Next, a boron-phosphorus-doped silicon oxide film 23 is formed on the thermal oxide film 22 by atmospheric pressure vapor deposition or reduced pressure vapor deposition.
It is formed in a thickness of about 0.4 to 0.8 μm.

Thereafter, a heat treatment is performed for about 10 to 40 minutes in an atmosphere of nitrogen and oxygen or a mixed gas of nitrogen and oxygen at about 850 to 1000 ° C., so that the boron / phosphorus-doped silicon oxide film 23 is glass-flowed. Thereafter, the contact holes 26 are selectively formed using photolithography and an etching method.

Next, as shown in FIG.
Of about 0.6 to 1.2 μm.

Next, as shown in FIG.
24 is entirely removed using an etching method. At this time, the polycrystalline silicon 24 is made to remain in the contact hole 26 at the height H, specifically, about 0.2 to 0.9 μm.

Thereafter, BF ₂ (boron fluoride) is ion-implanted on the entire surface or selectively, and BF ₂ having a profile is formed in the polycrystalline silicon 24 in the contact hole 26 at a temperature of 800 to 950 ° C.
A heat treatment is performed for about 10 to 30 minutes using the A (Furnace Anneal) method to diffuse polycrystalline silicon.

After that, PTA (Rapid Thermal Anneal)
A heat treatment is performed for about 5 to 40 seconds in an atmosphere of 1000 to 1500 ° C. by using the method, thereby activating the polycrystalline silicon 24 in the contact hole 26 and lowering the wiring resistance.

Finally, as shown in FIG.
Form 25.

(Problems to be Solved by the Invention) However, in the above-described method for manufacturing a semiconductor device, BF ₂ (boron fluoride) ion implantation is performed, and then a heat treatment at 800 to 950 ° C. is performed using the FA method. By performing the process for about 30 minutes, the phosphorus and the polycrystalline silicon 24 in the contact hole 26 are
And the resistance of the polycrystalline silicon 24 in the contact hole 26 increases.

SUMMARY OF THE INVENTION The present invention provides a method of manufacturing a semiconductor device which solves the problem of the prior art that the heat resistance using the FA method increases the wiring resistance of polycrystalline silicon in a contact hole. It provides a method.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention relates to a method of manufacturing a semiconductor device, the method comprising the steps of:
n: Iron and vapor deposition)
Alternatively, a step of simultaneously performing BF ₂ ion implantation and polycrystalline silicon deposition is introduced.

(Operation) According to the present invention, in a method of manufacturing a semiconductor element,
Since the steps described above were introduced, the 80
B or BF ₂ is uniformly present in the polycrystalline silicon in the contact hole without heat treatment at 0 to 950 ° C, preventing out-diffusion from the boron / phosphorus-doped silicon oxide film into the polycrystalline silicon. However, it acts to reduce the wiring resistance of polycrystalline silicon, and therefore, the above problem can be eliminated.

(Example) Hereinafter, an example of a method for manufacturing a semiconductor device of the present invention will be described with reference to the drawings. FIGS. 1 (a) to 1 (d) are process sectional views of one embodiment of the present invention. In FIGS. 1 (a) to 1 (d), FIGS. The same parts as those in FIG.

First, as shown in FIG. 1 (a), a thermal oxide film 22 is formed on a silicon substrate 21 to a thickness of about 0.02 to 0.05 .mu.m, and a boron-phosphorus-doped silicon oxide film is formed thereon by a normal pressure vapor deposition method or a low pressure vapor deposition method. 23 is formed in a thickness of about 0.4 to 0.8 μm.

Thereafter, the boron / phosphorus-doped silicon oxide film 23 is glass-flowed by a heat treatment of about 10 to 40 minutes in an atmosphere of about 850 to 1000 ° C. of nitrogen and oxygen or a mixed gas of nitrogen and oxygen to smooth the surface shape. .

Thereafter, the contact holes 26 are selectively formed using photolithography and an etching method.

Next, as shown in FIG.
Of B or BF ₂ ions and the deposition of polycrystalline silicon 24 are simultaneously performed using the IVD method to form a film of about 0.6 to 1.2 μm.

At this time, the growth rate of the polycrystalline silicon 24 was set to 20 ° / min or more, and the acceleration was set to 5 kev as the B or BF ₂ ion implantation condition.
~ 3 kev, dose 1.0 × 10 ¹³ ions / cm ² 〜1.0 × 10 ²⁰ ions / c
and m ^2.

Next, as shown in FIG. 1 (c), the formed polycrystalline silicon 24 is entirely removed by etching. At this time, the polycrystalline silicon 24 is made to remain in the contact hole 26 at a height H, specifically, about 0.2 to 0.9 μm.

Thereafter, a heat treatment is performed in an atmosphere at 1000 to 1500 ° C. for about 5 to 40 seconds by using the RTA method. Finally, Fig. 1 (d)
As shown in FIG. 7, a metal-based layer wiring 25 is formed.

(Effects of the Invention) As described above in detail, according to the present invention, the IV
By simultaneously implanting B or BF ₂ ions using the D method and depositing polycrystalline silicon, the heat treatment at 800 to 950 ° C. using the FA method can be performed without using the polycrystalline silicon in the contact hole. B or BF ₂ can be uniformly present in the silicon oxide film, the diffusion of phosphorus into the polycrystalline silicon from the boron-phosphorus-doped silicon oxide film can be eliminated, and the contact resistance can be kept low. And a highly reliable semiconductor device can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 (a) to 1 (d) are process cross-sectional views of an embodiment of a method for manufacturing a semiconductor device according to the present invention, and FIGS. 2 (a) to 2 (d). 2) is a process sectional view of a conventional semiconductor device manufacturing method. 21 ... silicon substrate, 22 ... thermal oxide film, 23 ... boron
Phosphorus-doped silicon oxide film, 24 ... Polycrystalline silicon, 25
…… Wiring, 26 …… Contact hole,

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01L 21/28-21/288 H01L 21/3205 H01L 21/768

Claims (1)

(57) [Claims] (A) forming a boron-phosphorus-doped silicon oxide film via a thermal oxide film formed on a silicon substrate; and (b) forming the thermal oxide film and the boron-phosphorus-doped silicon oxide film. Selectively forming a contact hole by using photolithography and etching selectively on the film; and (c) forming an IV on the boron-phosphorus-doped silicon oxide film.
A step of simultaneously implanting B or BF ₂ ions and depositing polycrystalline silicon by the method D to form polycrystalline silicon in which B or BF ₂ is uniformly distributed and performing a heat treatment; A method for manufacturing a semiconductor device, comprising: a step of removing crystalline silicon entirely by using an etching method to leave polycrystalline silicon only in the contact hole; and (e) a step of forming a wiring of a metal-based layer.