JP2928655B2 - Chemical vapor deposition equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical vapor deposition apparatus preferably used for forming a thin film in the manufacture of a semiconductor device, for example.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view showing a reactor chamber of a chemical vapor deposition apparatus disclosed in, for example, Japanese Patent Application Laid-Open No. 2-177424, wherein 1 is a silicon (Si) wafer, 2 is a rotary stage, Reference numeral 3 denotes a reaction gas, silane (SiH ₄ ) or oxygen (O ₂ ), which is converted into a carrier gas nitrogen (N
₂ ) Gas heads to be introduced together with 4)
Reference numeral 6 denotes an inlet for iH ₄ and O ₂ , and reference numeral 6 denotes an outlet. 7 is a heater, 8 is a cooling means, 9, 10 and 11 are flows of nitrogen gas introduced separately, and 12 is a reaction chamber.

Next, the operation of the conventional chemical vapor deposition apparatus configured as described above will be described. A semiconductor wafer 1 which is a film-forming object is fixed to a heating stage 2 provided in a reaction chamber 12 by evacuation by a transfer device (not shown). Next, SiH ₄ and O ₂ gases are sent from the respective supply ports 4 and 5 to the gas ejection head 3, and a reaction gas is ejected from a plurality of gas ejection holes 41 and 51 provided in the gas ejection head, thereby forming the semiconductor wafer 1. The semiconductor wafer 1 is introduced into the space on the surface and mixed, and is subjected to a thermochemical reaction.
A thin film is formed on the surface of. By the way, in this type of chemical vapor deposition apparatus, it is necessary to obtain a reaction product film having good coverage even with a high aspect ratio step with the increase in the density of the LSI.

[0004]

In the conventional chemical vapor deposition apparatus as described above, the surface reactivity (adhesion probability) coverage characteristic of the film-forming precursor is poor, and voids are formed or a uniform surface is formed. I can't get it. Further, when a film is formed at a step having a high aspect ratio, there is a problem that these tendencies are further increased. For example, when a film is formed in a trench having an aspect ratio of 0.5 (= D / W) (where D is the trench depth and W is the trench width) in a conventional apparatus, the film thickness in the depth direction of the trench is formed. Figure 4 shows the distribution of d.
Is shown by a circle as a conventional example. The values of d and d _max are as shown in the schematic diagram of FIG. 5, and as the depth of the trench becomes deeper, the d / d _max value decreases from 0.96 to 0.42, and the slope is large. If the film continues, there is a problem that the trench is not completely filled and a void is formed.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve such a problem, and a chemical vapor deposition apparatus capable of forming a reaction product film having good coverage even with a high aspect ratio step. The purpose is to obtain.

[0006]

According to the present invention, there is provided a chemical vapor deposition apparatus , comprising:
Attachment probability of radicals generated by gas phase reaction
Mesh-like body to trap large radicals
Things.

[0007]

[Operation] The mesh-like body of the present invention is formed by trapping a radical having a high adhesion probability among a plurality of radicals generated by a gas phase reaction, and performing film deposition using only a radical having a relatively low adhesion probability. To improve coverage characteristics.

[0008]

FIG. 1 is a sectional view of a reactor chamber of a chemical vapor deposition apparatus according to one embodiment of the present invention, and FIG. 2 is a top view thereof. In the figure, reference numeral 13 denotes a mesh-like body made of a mesh cage provided so that its upper surface is parallel to the surface of the semiconductor wafer 1 at a distance of about 0.6 mm, and has an outer diameter of 1 /.
It is in contact with a chemical vapor deposition apparatus via a ring 14 of a 4-inch stainless pipe. This ring 14 is connected to the mesh 13 but not to the device. Therefore, the mesh cage 13 can be easily replaced. Further, the mesh size of the cage can be arbitrarily changed according to conditions and the like. The other reference numerals are exactly the same as those of the above-mentioned conventional device, and therefore, the description is omitted.

Next, the operation will be described. The semiconductor wafer 1 is fixed to a heating stage 2 provided in a reaction chamber 12 by evacuation. Next, after setting the mesh cage 13, a mixed gas of SiH ₄ and nitrogen is supplied from the inlet _4, and a mixed gas of oxygen and nitrogen is supplied from the inlet 5, and the mixed gas is blown out from the gas outlets 41 and 51 to cause a reaction chamber. React in 12 This reaction produces various radicals,
Radicals with high attachment probability are “powder” (fine particles) in the gas phase
Are those easy to form, in fact this "powder" is observed as if it were a "cloud" just below the substrate during film formation.

In the above embodiment of the present invention, the trap is removed by the radical mesh cage 13 having a high adhesion probability, which deteriorates the coverage characteristic, and most of the film forming components are formed by the radicals having a low adhesion probability. 1 on which an insulating film having excellent coverage characteristics is an object to be formed
Formed on top. FIG. 4 shows the state of the film thickness in the depth direction of the trench when the mesh cage 13 was provided as an example in FIG.
Shown by a mark. As is clear from FIG. 4, the d / d _max value decreases from 1 to 0.71 as the trench groove becomes deeper, and the value is always larger and the slope is smaller than in the conventional example shown by a circle. That is, it is understood that the coverage characteristics are improved. In addition, as a result of measuring the deposition rate, it was found that a mesh cage was provided to reduce the deposition rate from 3120 ° / min to 1
810Å / min, which indicates that radicals are trapped and removed by the mesh cage 13. Note that the effect of the radical trap on the mesh depends on the opening diameter of the mesh.
The inventors have confirmed that a fineness of about inches or more is sufficiently effective.

[0011] Of the various radicals generated by the gas phase reaction, those having a high attachment probability include, for example, radicals such as SiH ₂ . Further, as a substance having a low attachment probability, for example, a radical such as SiH ₂ O can be mentioned. However, the chemical species of the radical, the attachment probability, and the like are not always clear and are not limited to the above. Further, the position where the mesh cage 13 is provided is preferably in the vicinity of a “cloud” formed at a position of about 1 mm from the surface of the substrate 1, specifically, 1 mm or less, particularly in the range of 0.5 mm to 1 mm. Is preferred.

In the above embodiment, a mesh cage is used as the mesh-like body, but the outer shape may not be necessarily cage-like. In short, it is sufficient that the reaction gas fed into the mesh cage 13 of FIG. 1 also flows to the side of the drawing . Further, the diameter, type, and the like of the wire constituting the mesh are not particularly limited, and the mesh is not limited to a mesh made of the wire. The above embodiment is merely an example for facilitating the understanding of the present invention, and it goes without saying that various other modifications and changes are possible.

[0013]

As described above, according to the present invention, the film formation
Between the gaseous substance and the gas head
Radicals with high attachment probability among the generated radicals
Is provided with the trap mesh-like material, it is possible to obtain a chemical vapor deposition apparatus capable of forming a reaction product film having good coverage even for high aspect ratio step.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of a chemical vapor deposition apparatus according to one embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view showing a reactor chamber portion of a conventional apparatus.

FIG. 4 shows a film thickness distribution in a trench groove depth direction obtained from a d / d _max value measured in a case where a film is formed in a trench having an aspect ratio of 0.5 using a conventional apparatus and the above embodiment. FIG.

FIG. 5 is a schematic diagram for explaining a state of film formation on a trench groove.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Film-forming object (semiconductor wafer) 12 Reaction chamber 13 Mesh body (mesh cage)

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Toru Yamaguchi 4-1-1 Mizuhara, Itami City, Kita Itami Works, Mitsubishi Electric Corporation (56) References JP-A-50-3269 (JP, A) JP-A-50- 92685 (JP, A) JP-A-63-235479 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 21/205 H01L 21/31

Claims (1)

(57) [Claims] 1. A gas head facing a semiconductor wafer.
Due to the thermochemical reaction of the ejected reaction gas, the semiconductor wafer
In a chemical vapor deposition apparatus with a film formed on the surface
The reaction between the film-forming object and the gas head.
Of the radicals generated by the gas phase reaction of gas,
A mesh that traps radicals with a high probability of arrival
A chemical vapor deposition apparatus characterized by comprising.