JP3111096B2 - CVD thin film forming equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a disk-shaped substrate held on a substrate holder having a substantially circular substrate holding surface.
A source gas diffusion flow path from the top of the substrate to the substrate,
A source gas discharge path extending downward from the side of the substrate holder, and irradiating a laser beam on the substrate substantially parallel to the film formation surface and in the vicinity of the film formation surface to form a thin film on the substrate. The present invention relates to a CVD thin film forming apparatus for forming a film.

[0002]

2. Description of the Related Art The structure of such a CVD thin film forming apparatus is shown in FIG. The apparatus 1 includes a thin film forming chamber 1a whose internal pressure can be adjusted, and a source gas supply unit 2 for supplying a source gas g into the thin film forming chamber 1a.
(The portion of the raw material gas supply path 2 that opens into the thin film forming chamber 1a is a nozzle 2a).
a, and a source gas discharge section 3 for discharging the raw material gas. The thin-film forming chamber 1a has an outer shell formed from a bottomed cylindrical member 1c having a lid 1b, and a disk-shaped substrate 4 on which a thin film is to be formed is provided in the center of the thin-film forming chamber 1a. Substrate holding table 7 having substrate holding surface 7a to be placed
Is arranged. The substrate holding table 7 is formed of a columnar member having a cross section perpendicular to the axis, and this surface is a substrate holding surface 7a. The substrate holding table 7 includes a resistance heating element 8 therein, and the heating element 8 heats the source gas g and the film 6 being formed. Further, a laser beam irradiation window 10 is provided in the thin film forming chamber 1a, and the source gas g in the upper region of the substrate is excited by the laser beam 9 introduced from the window 10. At the time of film formation, the substrate holding table 7 and its vicinity are heated to a temperature suitable for the formation (700 to 800 ° C. when the source gas excitation / film formation promoting energy is supplied only by heat, 350 ° C. when a laser is shared). The thin film 6 is formed while being held below (heating is performed by the above-described resistance heating element 8). At this time, in the thin film forming chamber 1a, the raw material gas g is diffused from the nozzle 2a toward the substrate 4 from above (this path is referred to as a diffused flow path gl), and a part of the raw material gas g
Is formed and consumed as a thin film 6, and the remainder moves to the side of the substrate holding table 7, and flows downward further from the side area of the substrate holding table 7 (this path is referred to as a discharge path). g2). Now, when the radius of the substrate 4 is R1 and the radius of the substrate holder 7 is R2, conventionally, R2 / R
1 was selected to be about 1.2 (6 inches / 5 inches).

[0003]

However, when such a dimensional relationship is selected, the thickness reduction δe of the outer end of the thin film with respect to the thickness δc of the thin film formed on the substrate is required.
(The thickness of the outer end portion of the thin film is slightly reduced). In addition, there has been a problem that the peripheral portion of the substrate having a small film thickness must be discarded as a defective portion. That is, for example, when the substrate is 5 inches, the product (about 15% of the entire substrate area) formed at the outer end portion which is about 5 mm from the outer end is discarded. Therefore, conventionally,
Product yield was poor and production efficiency was poor. Accordingly, an object of the present invention is to provide a CVD thin film forming apparatus as described above, wherein the thickness of the thin film formed on the peripheral portion of the substrate does not greatly differ from the thickness of the thin film formed on the substrate, and is formed on almost the entire substrate. It is an object of the present invention to obtain a CVD thin film forming apparatus which can use a manufactured product, has a good yield, and has a high production efficiency.

[0004]

The feature of the structure of the CVD thin film forming apparatus according to the present invention for achieving this object is that when the radius of the substrate is R1 and the radius of the substrate holder is R2, R2 / R1 Is set to 2 or more, and the operation and effect are as follows.

[0005]

In other words, by setting the relationship between the radius of the substrate and the diameter of the substrate holding table to be two or more, the source gas diffused down from the upper portion of the substrate is conventionally diffused along the film forming surface of the substrate. Becomes As a result, in the state of film formation on the substrate, the state of the edge portion approaches the state near the center (there is no difference between the two portions). Therefore, the difference in thickness between the thin film formed on the edge of the substrate and the film near the center is eliminated. One example of this result is shown in FIGS. 2, 3 and 4. In FIG R2 / R1 in the horizontal axis is the ratio of the thickness of the edge portion on the vertical axis [delta] _e and NarumakuAtsu [delta] _c is shown. When clearly seen R2 / R1 to 2 or more from the figure, the ratio of the thickness [delta] _e and NarumakuAtsu [delta] _c of edge satisfies the general acceptance criteria becomes 3% or less.

[0006]

As a result, the difference between the thickness of the substrate and the thickness of the outer peripheral portion can be suppressed to within 3%, and the portion near the edge which has been discarded conventionally can be handled as a good product. As a result, the entire outer peripheral portion can be used, thereby improving the product yield.

[0007]

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a configuration of a CVD thin film forming apparatus 1 of the present application. This CVD thin film forming apparatus 1 is a so-called laser CVD.
This is a thin film forming apparatus, in which heat gas supplied by a heating element and light energy supplied by a laser beam excite a source gas and form a film. Since this laser CVD thin film forming apparatus can form a film at a lower temperature than a conventional simple CVD thin film forming apparatus, there is an advantage that a high quality film can be formed without causing thermal damage to a substrate or the like. . Below, semiconductors (IC, L
An example in which the thin film layer 6 is formed on the substrate 4 will be described. Here, the substrate 4 is a silicon substrate as an example, and a thin film 6 of silicon oxide which is an insulating film or a passivation film is formed on the substrate 4.

The configuration of the device 1 is substantially the same as the configuration described in the conventional example. The difference between the conventional and the present invention is the ratio of the diameter of the substrate holding table 7 to the diameter of the substrate 4,
This is taken largely in the present application. To explain the actual numerical values, the diameter of the substrate is 5 inches (127 mm), the inner diameter of the cylindrical member is 350 mm, the diameter of the substrate holder is 10 inches (254 mm), the diameter of the nozzle is 6 mm, and the separation distance between the nozzle blowing portion and the substrate is
0 mm. Here, as a preferable range, the substrate 4
And the linear velocity of the raw material gas (g) flowing down from the nozzle 2a is 450-800 cm / min when the ratio of the diameter of the substrate holding table 7 to the inner diameter of the cylindrical member 1c is in the range of 1: 2: 2.5-3.
It is.

A state in which a thin film 6 is formed on a substrate 4 using the apparatus 1 of the present invention will be described below. The inside of the thin film forming chamber 1a is maintained in a temperature range of about 350 ° C. by a resistance heating element 8, and SiH ₄ and N ₂ O as source gas g are supplied from a nozzle 2a provided at the tip of the source gas supply unit 2. Supplied. Total flow rate of raw gas is 60-100cc
/ Min (including N ₂ carrier gas). The source gas g diffuses and flows down from the nozzle to the substrate upper region 4a. And this raw material gas g at this part 4a
Energy is supplied by the resistance heating element 8. on the other hand,
Energy is also supplied from the laser light 9 incident from the laser light irradiation window 10. As a result, this site 4 on the substrate
Excited by a, it is dissociated, and falls on the substrate 4 as a nucleus in an initial stage. When the nucleation is completed, the nucleus is grown as a SiO ₂ film on the substrate 4 around the nucleus. Thus, the film formation on the substrate 4 can be completed.

[Another Embodiment] An embodiment of the present invention will be described below. (B) In the above embodiment, the case where the configuration of the present invention is applied to the laser CVD apparatus using the laser beam 9 as the means for exciting and dissociating the source gas has been described. Can be applied to any material that supplies a raw material gas or the like to form a thin film. An example of such is a simple thermal CVD apparatus. (B) In the above embodiment, SiO ₂ was deposited on the Si substrate.
Although an example of forming a film has been described, as a source gas,
The configuration of the present application can also be adopted when forming a SiN film using (SiH ₄ NH ₃ ) and (Si ₂ H ₆ NH ₃ ) as a pair.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a CVD thin film forming apparatus of the present invention.

FIG. 2 is a diagram showing a state of a film formed under the conditions of the present application.

FIG. 3 is a diagram showing a state of a film formed under conventional conditions.

FIG. 4 is an explanatory diagram showing a relationship between a radius ratio and a film thickness.

FIG. 5 is a diagram showing a configuration of a conventional CVD thin film forming apparatus.

[Explanation of symbols]

 1b Lid 1c Cylindrical member 2a Nozzle 4 Substrate 6 Thin film 7 Substrate holding table 7a Substrate holding surface 9 Laser beam g Raw material gas g1 Diffusion down flow g2 Exhaust flow

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shigeru Morikawa 17 Kando-ji Minamicho, Shimogyo-ku, Kyoto-shi, Kyoto Inside Kansai New Technology Research Institute Co., Ltd. (56) References JP-A-4-221078 3-38357 (JP, U) JP-A-2-146423 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) C23C 16/00-16/56 H01L 21/205 H01L 21 / 31

Claims (2)

(57) [Claims] 1. A disk-shaped substrate (4) held on a substrate holding table (7) having a substantially circular substrate holding surface (7a), from above the substrate (4). ) And a discharge path (g2) for the source gas (g) directed downward from the side of the substrate holding table (7). A laser beam (9) substantially parallel to 4) and near the substrate (4);
And forming a thin film (6) on the substrate (4), wherein the radius of the substrate (4) is R1, and the radius of the substrate holder (7) is R2. In some cases, R2 / R1 is set to 2 or more. 2. The substrate holding table (7) is formed of a columnar member having an upper cross section perpendicular to an axis and serving as the substrate holding surface (7a). (1
b) a cylindrical member (1c) provided with
And a nozzle (2a) for introducing the source gas (g) into the thin film formation chamber (1a) is provided at the center of the lid (1b). (4) Diameter of substrate holding table (7) and cylindrical member (1)
The ratio of the inner diameter of c) is 1: 2: 2.5 to 3, and the nozzle (2)
The linear velocity of the raw material gas (g) flowing down from a) is 450 to 8
2. The CVD thin film forming apparatus according to claim 1, wherein the pressure is 00 cm / min.