JP2529267B2 - Film forming equipment - Google Patents

Description

The present invention relates to a film forming apparatus for forming a film on a substrate in a reduced pressure gas atmosphere.

[Prior Art] Conventionally, in a film forming apparatus for forming a film on a substrate in a depressurized gas atmosphere, a gas pressure control unit, a substrate temperature control unit, a bias voltage control unit, and the like are individually controlled. After the film formation was completed, it was necessary to evaluate the film stress and carefully examine the film formation conditions so that the target film stress could be obtained.

[Problems to be Solved by the Invention] By the way, if warpage occurs on a substrate during film formation of a semiconductor,
This causes problems during patterning, and also causes problems such as film peeling and cracks. Also, when forming a magnetic material,
The magnetic properties are affected by the stress of the film.

The warp of the substrate caused by the stress of the film at the time of film formation is caused by, for example, the gas pressure (FIG. 5), the substrate temperature (FIG. 6) during film formation, and the substrate It changes depending on the applied bias voltage (FIG. 7) and the like.

However, in the above-mentioned conventional example, in order to obtain the target stress of the film, the film pressure such as the gas pressure during the film formation, the substrate temperature, and the bias voltage applied to the substrate must be carefully examined. When the target stress is not obtained, there is a problem that the formed film is wasted.

[Means for Solving Problems] A film forming apparatus according to the present invention is a film forming apparatus for forming a film on a substrate, and a film stress detecting means for detecting a stress during film forming on the substrate as needed, and the detecting means. Compare the result with the target value,
It is characterized by comprising film forming condition control means for controlling film forming conditions so as to obtain the film stress of the target value, and film forming means for forming a film based on the control.

[Operation] According to the present invention, the film stress is detected by the film stress detecting means including the sensor, and the film forming condition control means for controlling the film forming condition is provided according to the detection result. The stress of the inner film can be controlled to a target value.

[Embodiment] FIG. 1 is a schematic configuration diagram showing an embodiment of a film forming apparatus according to the present invention.

In the figure, the chamber 1 is connected to a gas cylinder 3 via a gas introduction valve 2 that adjusts the pressure of gas during film formation, and is also connected to an exhaust device 5 via an exhaust valve 4.

A conductive substrate holder 7 is provided in the chamber 1 via an insulator 6, and the substrate holder 7 has a substrate 8
The material 9 for film formation is placed on the holder 10 under the holder 7 to which is fixed, facing the substrate 8, and in the holder 7, the substrate heater 11 and the stress sensor.
12- is arranged.

The stress sensor 12 has a surface 8b opposite to the film formation surface 8a of the substrate 8.
The probe 13 of the stylus type is provided at the position 1, and the warp of the substrate 8 caused by the film stress is detected as the film is formed, and the value is converted into the stress.

The film forming apparatus having such a configuration is a film forming condition control unit.
Controlled by 20.

The film formation condition controller 20 receives a signal from the film stress detector 21, and applies a bias to the gas pressure controller 22 that controls the gas introduction valve 2, the substrate temperature controller 23 that controls the substrate heater 11, and the substrate holder 7. The bias voltage controller 24 that applies a voltage is controlled to control the stress of the film being formed so as to match the target value. The film stress detection unit 21 compares the stress detected by the stress sensor 12 with the target stress, and outputs the comparison result.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG.

First, the exhaust valve 4 is opened, and the inside of the chamber 1 is decompressed by using the exhaust device 5.

Next, the gas control unit 22 controls the gas introduction valve 2 so that the gas pressure PG in the chamber 1 becomes the initial pressure PG ₀ , and the gas in the gas cylinder 3 is introduced into the chamber 1. Also,
The substrate temperature controller 23 controls the substrate heater 11 so that the substrate temperature TS becomes the initial set temperature TS ₀ , and the bias voltage
The bias voltage control unit 24 applies a bias voltage to the substrate 8 through the substrate holder 7 so that VS becomes the initial voltage VS ₀ (step 30).

When the initial setting conditions are satisfied in this way, the film forming material 9 held by the holder 10 is released, and a film is formed on the film forming surface 8a of the substrate 8 (step 31).

As the film is formed on the substrate 8, the stress δ of the film causes the substrate 8 to warp.
The film stress δ ₀ detected by 12 and targeted by the film stress detector 21
And the actual film stress δ are compared (step 32).

If the actual film stress δ does not match the target film stress δ ₀ , the condition of step 32 is NO, and the film stress detection unit 21 issues a command to change the film forming conditions so that they match. Output to the film condition control unit 20. Upon receipt of the command, the film formation condition control unit 20 issues a film formation condition command to the gas pressure control unit 22, the substrate temperature control unit 23, and the bias voltage control unit 24, respectively, and the stress δ during film formation is set to a set stress δ _0. Substrate temperature T in the direction that matches
S, bias voltage VS, and gas pressure PG are changed within the allowable range (step 33).

 Then, the operations of steps 31 and 32 are repeated.

If the actual film stress δ matches the target film stress δ ₀ , the thicknesses are compared (step 34).

If the thickness does not reach the target value, steps 31 to 33 described above are repeated, and when the target value is reached, the apparatus stops (step 35).

As described above, the film stress sensor 12 and the film stress detection unit
By providing 21 and the film formation condition control unit 20, the stress of the film being formed can be controlled to a target value.

FIG. 3 shows another embodiment of the stress sensor 12, in which a mirror section 40 is provided at a position deviated from the center of the surface 8b of the substrate 8 and the light emitted from the laser oscillator 41 is reflected by this mirror section 40.
The sensor 42 is configured to receive the reflected laser light.

With such a configuration, when the substrate 8 warps due to the stress of the formed film, the mirror portion 40 tilts, so that the laser light reflected by the mirror portion 40 moves on the sensor 42. To do. This movement is detected by the sensor 42 and converted into film stress.

Depending on the type of substrate, the mirror portion may be omitted and the substrate may be used directly as the mirror portion. Further, if the film forming conditions allow, a laser oscillator and an optical sensor may be provided on the film forming surface side of the substrate and the formed film may be used as the mirror portion.

FIG. 4 shows still another embodiment of the stress sensor 12, in which a pair of electrodes 50 and 51 are provided on the surface 8b of the substrate 8, a film is formed on the substrate 8 and the substrate 8 is warped by the stress of the film. When it occurs, the position of the electrode 50 shifts and the capacitance between the electrodes 50 and 51 changes. Therefore, this variation can be detected by the capacitance meter 52 and converted into the stress of the film.

[Effects of the Invention] As described in detail above, according to the present invention, film forming conditions are controlled by a film stress detecting means including a sensor for detecting the stress of a film being formed and a film stress detection result. By providing the film condition control means, it is not necessary to carefully examine the film forming conditions such as the gas pressure during the film formation, the substrate temperature, the bias voltage applied to the substrate, and the unnecessary film formation. It is possible to control the stress of the film in the film to a target value.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of a film forming apparatus according to the present invention, FIG. 2 is a flow chart for explaining the operation of the embodiment shown in FIG. 1, and FIG. 3 is a stress sensor. FIG. 4 is a configuration diagram showing another embodiment of the stress sensor, FIG. 4 is a configuration diagram showing still another embodiment of the stress sensor, FIG. 5 is a characteristic diagram showing the relationship between the warp of the substrate and the gas pressure, and FIG. FIG. 7 is a characteristic diagram showing the relationship between the substrate warp and the substrate temperature. FIG. 7 is a characteristic diagram showing the relationship between the substrate warp and the bias voltage applied to the substrate. 1 ... Chamber 2 ... Gas introduction valve 7 ... Substrate holder 8 ... Substrate 11 ... Substrate heater 12 ... Stress sensor 20 ... Deposition condition control unit 21 ... Membrane stress detection unit 22 ... Gas pressure Controller 23 …… Substrate temperature controller 24 …… Bias voltage controller

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Takeshi Osato 1248 Shimokagemori, Chichibu City, Canon Electronics Co., Ltd. (72) Hiroichi Goto 1248, Shimokagemori, Chichibu City, Canon Electronics Co., Ltd. (72) ) Inventor Shuzo Yasuhiko 1248 Shimokagemori, Chichibu, Japan Inside Canon Electronic Co., Ltd. (56) Reference JP-A-63-290259 (JP, A)

Claims (2)

(57) [Claims] 1. In a film forming apparatus for forming a film on a substrate, a film stress detecting means for detecting a stress during film formation of the substrate is compared with the detection result and a target value, and the target value of the target value is compared. A film forming apparatus comprising: a film forming condition control unit that controls a film forming condition so as to obtain a film stress; and a film forming unit that forms a film based on the control. 2. The film forming apparatus according to claim 1, wherein the film forming conditions are a gas pressure, a substrate temperature, and a bias voltage applied to the substrate.