JP2005039123A - Chemical vapor deposition device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chemical vapor deposition device which further improves uniformity of a film formed on a semiconductor substrate. <P>SOLUTION: Two reaction chambers 3 are provided to a chamber of a chemical vapor deposition device. In each of the reaction chambers 3, a shower head 5 for blowing off a material gas and an oxidant and a stage part 7 for mounting a semiconductor substrate are arranged to face each other. A lift bellows 4 is provided to a rear side of the shower head 5 circumferentially. A driving part 6 is provided above the reaction chamber 3 for driving the lift bellows 4 thereof. The distance between the shower head 5 and the stage 7 is changed by expanding or contracting the lift bellows 4 by the driving part 6. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a chemical vapor deposition apparatus, and more particularly to a single wafer chemical vapor deposition apparatus.

  In the manufacture of semiconductor devices, chemical vapor deposition apparatuses are widely used to form a predetermined film on a semiconductor substrate. As one such chemical vapor deposition apparatus, for example, Patent Document 1 discloses a chemical vapor phase in which a silicon oxide film or the like is formed (film formation) by vaporizing a liquid material such as TEOS (Tetra Ethyl Ortho Silicate). Growth devices have been proposed.

  In this chemical vapor deposition apparatus, a plurality of film formation heads are arranged from a first film formation head to a fifth film formation head for film formation. In each film forming head, one reaction chamber is configured, and a gas shower head for blowing out gas and a stage for mounting a semiconductor substrate so as to face the gas shower head are arranged. . In the film formation head, the film formation process is performed for each semiconductor substrate placed on the stage.

Each film forming head is individually provided with a material gas supply system, and the supply amount of the material gas is controlled in accordance with each purpose. For example, when a TEOS / ozone (O ₃ ) NSG (Non doped Silicate Glass) film is formed, the supply amount of TEOS and ozone is controlled.

In addition, when a TEOS / ozone (O ₃ ) -based BPSG (Boro Phopho Silicate Glass) film is formed, the supply amount of a gas obtained by vaporizing a predetermined liquid material for adding TEOS and impurities is controlled. It will be.
Japanese Patent Laid-Open No. 7-221090

  In recent years, a chemical vapor deposition apparatus has been proposed in which a chamber is provided from the viewpoint of further improving the processing capability of a single-wafer chemical vapor deposition apparatus, and a plurality of deposition heads (reaction chambers) are provided in the chamber. Yes.

  However, in such a chemical vapor deposition apparatus, since a plurality of reaction chambers are provided in one chamber, it is formed on a semiconductor substrate only by controlling the amount of gas supplied to one chamber. There was a limit to further improving the uniformity of the film. Note that the uniformity of the film means the uniformity of the film thickness within the semiconductor substrate or between the semiconductor substrates, the uniformity of the impurity concentration in the film, and the like.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a chemical vapor deposition apparatus that further improves the uniformity of a film formed on a semiconductor substrate.

  The chemical vapor deposition apparatus according to the present invention includes a chamber having a reaction chamber, a gas outlet, a stage unit, a gas supply control unit, and a tilt mechanism. The gas outlet is disposed in the reaction chamber and blows out a predetermined material gas. The stage portion is disposed in the reaction chamber so as to face the gas outlet, and a semiconductor substrate is placed thereon. The gas supply control unit supplies a material gas at a predetermined flow rate to the gas outlet. The tilt mechanism is provided in at least one of the gas outlet and the stage part, and changes the interval between the gas outlet and the stage part.

  According to the chemical vapor deposition apparatus of the present invention, when the uniformity of the film formed on the semiconductor substrate deteriorates, even if it is difficult to improve the uniformity only by the gas supply control unit, By providing the tilt mechanism in at least one of the stage portions, the distance between the gas outlet and the stage portion (semiconductor substrate) can be changed within the surface of the semiconductor substrate. As a result, the growth rate of the film can be adjusted by changing the flow of the material gas on the semiconductor substrate surface, and as a result, the uniformity of the film can be improved.

  Examples according to the present invention will be specifically described below.

  First, a chemical vapor deposition apparatus according to Example 1 of the present invention will be described. In this chemical vapor deposition apparatus, a material gas obtained by vaporizing a predetermined liquid source and an oxidant are fed into a chamber, and a film is formed on the semiconductor substrate by reacting the material gas and the oxidant.

  As shown in FIG. 1, as a liquid source supply source for supplying a predetermined liquid source, for example, a first liquid source supply source 11 for supplying TEPO (Tri Ethyl Phosphate), a first source for supplying TEB (Tri Ethyl Borate), A second liquid source supply source 12 and a third liquid source supply source 13 for supplying TEOS are provided.

  Vaporizers 18, 19, and 20 are provided for vaporizing liquid raw materials sent from the first liquid raw material supply source 11, the second liquid raw material supply source 12, and the third liquid raw material supply source 13, respectively. Nitrogen gas and helium gas are fed from a nitrogen supply source 14 and a helium supply source 15, respectively, in order to vaporize and send the liquid raw material in the vaporizers 18, 19, and 20, respectively.

  On the other hand, an ozone supply source 16 for supplying ozone as an oxidant is provided, and oxygen is sent from an oxygen supply source 17 to send out ozone sent from the ozone supply source 16.

  The material gases vaporized by the vaporizers 18, 19, and 20 are sent to the chamber 1 through the material gas supply line 31. Ozone is sent to the chamber 1 via the ozone supply line 32. The chamber 1 is provided with two reaction chambers 3. In order to individually control the flow rate of the material gas to be supplied to each of the two reaction chambers 3, the material gas supply line 31 is provided with a flow rate control valve 9 corresponding to each reaction chamber 3.

  In each of the reaction chambers 3, a shower head 5 for blowing out a material gas and an oxidant and a stage portion 7 for placing a semiconductor substrate (not shown) are disposed so as to face each other. Yes. The chamber 3 is provided with an exhaust line 33 for exhausting the inside of the chamber 3. The exhaust line 33 is connected to the exhaust pump 21.

  Next, the structure around the reaction chamber 3 will be described in more detail. As shown in FIG. 2, a lift bellows 4 is provided in the circumferential direction on the back side of the shower head 5, and a drive unit 6 for driving the lift bellows 4 is provided above the reaction chamber 3. . As shown in FIG. 3, the lift bellows 4 is expanded and contracted by the drive unit 6, thereby changing the distance between the shower head 5 and the stage 7.

  Next, the operation of the above-described chemical vapor deposition apparatus will be described. The liquid raw material sent from each of the first liquid raw material supply source 11, the second liquid raw material supply source 12, and the third liquid raw material supply source 13 is sent to the vaporizers 18, 19, and 20 to be vaporized into a material gas. The vaporized material gas is mixed with nitrogen gas and helium gas, and sent to the chamber 3 through the material gas supply line 31. On the other hand, ozone gas supplied from the ozone supply source 16 is sent to the chamber 3 through the ozone supply line 32.

  The material gas and ozone gas sent to the chamber 3 are blown out from the shower head 5 into the reaction chamber 3. The semiconductor substrate 2 is placed on the stage 7, and the semiconductor substrate 2 is mounted on the stage 7 and heated by a heater (not shown) set to a temperature of about 480 ° C.

  The material gas and ozone gas introduced into the reaction chamber 3 react on the surface of the semiconductor substrate 2 to form a predetermined film. In this case, a BPSG film is formed on the semiconductor substrate by using TEB, TEPO, and TEOS as liquid raw materials.

  At this time, the pressure in the reaction chamber 3 is set to an optimum pressure by the semiconductor device (device) to be processed, and is set to, for example, normal pressure (atmospheric pressure) or pressure of 10,000 Pa or higher (depressurized state).

  The material gas after the reaction is exhausted out of the reaction chamber 3 through the exhaust line 33 by the exhaust pump 21. In this way, a series of processes for forming a predetermined film such as a BPSG film on the semiconductor substrate is completed.

  In the chemical vapor deposition apparatus described above, two reaction chambers 3 are provided in one chamber 1 as shown in FIG. A material gas supply line branched from the material gas supply line 32 is connected to each of the reaction chambers 3, and the flow rate of the material gas introduced into the reaction chamber 3 is controlled by the flow rate control valve 9.

  Further, as shown in FIGS. 2 and 3, a lift bellows 4 is provided on the back side of the shower head 5, and the lift bellows 4 is expanded and contracted by the drive unit 6, thereby reducing the distance between the shower head 5 and the stage 7. Can be changed.

  Thereby, for example, when the film thickness uniformity of the film formed on the semiconductor substrate deteriorates, it is difficult to improve the uniformity only by controlling the flow rate of the material gas introduced into the reaction chamber 3 by the flow rate control valve 9. Even so, the uniformity can be improved. This will be described.

  For example, as shown in FIG. 4, it is assumed that the film thickness distribution in the radial direction of the semiconductor substrate (wafer) tends to gradually decrease from one end of the wafer toward the other end. In this case, as shown in FIG. 5, the lift bellows 4 located at the thin film portion is extended to bring the shower head 5 closer to the semiconductor substrate 2 side, or conversely, located at the thick film portion. The lift bellows 4 is contracted to move the shower head 5 away from the semiconductor substrate 2 side.

  By doing so, the interval L1 between the shower head 5 and the semiconductor substrate 2 in the portion corresponding to the thin portion is larger than the interval L2 between the shower head 5 and the semiconductor substrate 2 in the portion corresponding to the thick portion. Will also be shorter. That is, the distance between the shower head 5 and the semiconductor substrate 2 can be changed in the semiconductor substrate surface 2.

  By performing the film formation process in this state, the growth rate of the film is increased at the portion corresponding to the initial thin film portion of the wafer, while the film growth rate is decreased at the portion corresponding to the thick film portion. Thus, the film thickness distribution in the radial direction of the wafer can be made constant. As a result, it is possible to improve the film thickness uniformity in the semiconductor substrate.

  Even when the uniformity of the impurity concentration varies, it is possible to improve the uniformity of the impurity concentration by taking similar measures.

  In this chemical vapor deposition apparatus, the case where four lift bellows are provided on the shower head 5 side has been described. However, by increasing the number of lift bellows, the distance between the shower head 5 and the semiconductor substrate 2 can be further increased. It can be set precisely.

  Furthermore, by monitoring the flow rate of the material gas that actually flows through the flow rate control valve 9 that controls the flow rate of the material gas, the flow rate difference of the material gas flowing between the reaction chambers can be obtained, and the flow rate difference is constant. If the value is exceeded, an alarm can be issued to detect abnormalities in the chemical vapor deposition apparatus at an early stage.

  Further, when the shower head 5 and the stage 7 after the maintenance of the reaction chamber 3 are attached, the lift bellows 4 is provided so that the distance between the shower head 5 and the stage 7 can be easily adjusted.

  Here, a case where the lift bellows is disposed on the stage side will be described as an example. As shown in FIG. 6, a lift bellows 8 is provided in the circumferential direction on the back side of the stage 7, and a drive unit 6 for driving the lift bellows 8 is provided below the reaction chamber 3. As shown in FIG. 7, the lift bellows 8 is expanded and contracted by the drive unit 6, thereby changing the distance between the shower head 5 and the stage 7.

  Since the configuration other than this is the same as the configuration shown in FIG. 1 described above, the same members are denoted by the same reference numerals and detailed description thereof is omitted.

  In the chemical vapor deposition apparatus described above, a lift bellows 8 is provided on the back side of the stage 7 as shown in FIGS. Thereby, the lift bellows 8 can be expanded and contracted by the drive unit 6 to change the distance between the shower head 5 and the stage 7.

  Thereby, when the film thickness uniformity of the film formed on the semiconductor substrate deteriorates, it is difficult to improve the uniformity only by controlling the flow rate of the material gas introduced into the reaction chamber 3 by the flow rate control valve 9. Even if it exists, the improvement of uniformity can be aimed at. This will be described.

  For example, as shown in FIG. 8, it is assumed that the film thickness distribution in the radial direction of the semiconductor substrate (wafer) tends to gradually increase from one end of the wafer toward the other end. In this case, as shown in FIG. 9, the lift bellows 8 located in the thin film portion is extended to bring the stage 7 closer to the shower head 5, or conversely, the lift located in the thick film portion. The bellows 8 is shrunk and the stage 7 is moved away from the shower head 5 side.

  By doing so, the interval L1 between the shower head 5 and the semiconductor substrate 2 in the portion corresponding to the thin portion is larger than the interval L2 between the shower head 5 and the semiconductor substrate 2 in the portion corresponding to the thick portion. Will also be shorter.

  By performing the film formation process in this state, the growth rate of the film is increased at the portion corresponding to the initial thin film portion of the wafer, while the film growth rate is decreased at the portion corresponding to the thick film portion. Thus, the film thickness distribution in the radial direction of the wafer can be made constant. As a result, it is possible to improve the film thickness uniformity in the semiconductor substrate.

  Even when the uniformity of the impurity concentration varies, it is possible to improve the uniformity of the impurity concentration by taking similar measures.

  In this chemical vapor deposition apparatus, the case where four lift bellows are provided on the stage 7 side has been described. However, by increasing the number of lift bellows, the distance between the shower head 5 and the semiconductor substrate 2 can be made more precise. Can be set to

  Further, like the above-described chemical vapor deposition apparatus, when the shower head 5 and the stage 7 after the maintenance of the reaction chamber 3 are attached, the lift bellows 8 is provided, so that the shower head 5 and the stage 7 It is easy to adjust the interval.

  Here, a chemical vapor deposition apparatus in which an exhaust line is connected to each of two reaction chambers 3 provided in one chamber 1 will be described as an example. As shown in FIG. 10, a plurality of exhaust lines 33 are connected to each of the two reaction chambers 3.

  As shown in FIG. 11, exhaust lines 33 a to 33 d are connected to one reaction chamber 3 at positions corresponding to the four corners of the reaction chamber 3. An exhaust flow rate control valve 10 for controlling the exhaust flow rate is attached to each of the exhaust lines 33a to 33d. Since the configuration other than this is the same as the configuration shown in FIG. 1 described above, the same members are denoted by the same reference numerals and detailed description thereof is omitted.

  In the chemical vapor deposition apparatus described above, as shown in FIGS. 10 and 11, the exhaust lines 33 a to 33 in which the exhaust flow rate valves 10 are respectively attached to the one reaction chamber 3 at positions corresponding to the four corners of the reaction chamber 3. 33d is connected.

  As a result, when the film thickness uniformity of the film formed on the semiconductor substrate and the uniformity of the impurity concentration deteriorate, the uniformity cannot be achieved only by controlling the flow rate of the material gas introduced into the reaction chamber 3 by the flow rate control valve 9. Even if improvement is difficult, it is possible to improve uniformity. This will be described.

  For example, as shown in FIG. 12, it is assumed that the film thickness distribution and the impurity concentration distribution in the radial direction of the semiconductor substrate (wafer) tend to gradually increase from one end of the wafer toward the other end. To do. In this case, as shown in FIG. 13, the exhaust flow rate valve 10 of the exhaust lines 33c and 33d connected to the thin film thickness portion and the low impurity concentration portion is closed, and the thick film thickness portion and the impurity concentration. The exhaust flow rate valve 10 of the exhaust lines 33a and 33b connected to the higher portion side is opened.

  By performing the film formation process in this state, the exhaust flow rate decreases at the portion corresponding to the initial thin film portion of the wafer and the growth rate of the film increases, while the exhaust flow rate at the portion corresponding to the thick film portion. As a result, the growth rate of film formation decreases.

  Thereby, the distribution of the film thickness in the radial direction of the wafer and the distribution of the impurity concentration can be made constant, and the uniformity of the film thickness and impurity concentration in the semiconductor substrate can be improved.

  In this chemical vapor deposition apparatus, the case where the exhaust lines 33a to 33d are connected to the positions corresponding to the four corners of the reaction chamber 3 has been described, but the material gas in the reaction chamber 3 can be increased by increasing the number of exhaust lines. Can be controlled more precisely.

  Further, when dry cleaning is performed after the film forming process, the degree of opening / closing of the exhaust amount control valve 10 of the exhaust line 33 connected to each reaction chamber 3 is controlled to clean the inside of the reaction chamber 3. Gas can be retained. Thereby, the reaction product adhering to the portion that is difficult to remove in the reaction chamber 3 can be removed relatively easily. As a result, foreign substances in the reaction chamber 3 can be reduced and the maintenance cycle can be extended.

  Furthermore, in Example 1, when a plurality of lift bellows 4 is provided on the shower head 5 side, in Example 2, when a plurality of lift bellows 4 is provided on the stage 7 side, in Example 3, one reaction chamber 3 is provided. Although a case where a plurality of exhaust lines are connected to each other is described as an example, in one chemical vapor deposition apparatus, lift bellows are provided on both sides of a shower head and a stage, and one reaction chamber is provided. A plurality of exhaust lines may be connected.

  Thereby, the distance between the shower head and the semiconductor substrate can be controlled more precisely, and the flow of the material gas can also be controlled. As a result, it is possible to further improve the uniformity of the film thickness and impurity concentration in the semiconductor substrate surface.

  Further, although TEB, TEPO, and TEOS are given as examples of the liquid material of the film formed on the semiconductor substrate, the liquid material is not limited to this.

  The present invention is effectively applied to a structure that improves the uniformity of a film in a chemical vapor deposition apparatus that forms a predetermined film on a semiconductor substrate by introducing a predetermined material gas and an oxidant into the chamber. .

It is a figure which shows the structure of the chemical vapor deposition apparatus which concerns on Example 1 of this invention. In the same Example, it is the elements on larger scale of a reaction chamber. In the Example, it is a perspective view which shows a lift bellows and a shower head. In the Example, it is a figure which shows an example of the film thickness distribution with respect to the wafer diameter for demonstrating the effect of a chemical vapor deposition apparatus. FIG. 5 is a diagram showing a positional relationship between a gas shower head and a stage for eliminating the film thickness distribution shown in FIG. 4 in the same example. It is the elements on larger scale of the reaction chamber in the chemical vapor deposition apparatus which concerns on Example 2 of this invention. In the Example, it is a perspective view which shows a lift bellows and a shower head. In the Example, it is a figure which shows an example of the film thickness distribution with respect to the wafer diameter for demonstrating the effect of a chemical vapor deposition apparatus. FIG. 9 is a diagram showing a positional relationship between a gas shower head and a stage for eliminating the film thickness distribution shown in FIG. 8 in the same example. It is the elements on larger scale of the reaction chamber in the chemical vapor deposition apparatus which concerns on Example 3 of this invention. In the same Example, it is a top view which shows the arrangement | positioning relationship between a reaction chamber and an exhaust line. In the Example, it is a figure which shows an example of the film thickness distribution and impurity concentration distribution with respect to the wafer diameter for demonstrating the effect of a chemical vapor deposition apparatus. In the same Example, it is a figure which shows the mode of opening and closing of the exhaust flow control valve of the reaction chamber and exhaust line for eliminating the film thickness distribution and impurity concentration distribution which are shown in FIG.

Explanation of symbols

1 chamber, 2 semiconductor substrate, 3 reaction chamber, 4,8 lift bellows, 5 shower head, 6 drive unit, 7 stage, 9 flow control valve, 10 exhaust flow control valve, 11 first liquid source supply source, 12 second Liquid source supply source, 13 3rd liquid source supply source, 14 N ₂ supply source, 15 He supply source, 16 O ₃ supply source, 17 O ₂ supply source, 18 1st vaporizer, 19 2nd vaporizer, 20 1st 3 vaporizers, 21 exhaust pump, 31 material gas supply line, 32 ozone supply line, 33 exhaust line.

Claims (6)

A chamber having a reaction chamber;
A gas blowout port disposed in the reaction chamber for blowing out a predetermined material gas;
A stage portion disposed in the reaction chamber so as to face the gas outlet and on which a semiconductor substrate is placed;
A gas supply control unit for supplying a material gas at a predetermined flow rate to the gas outlet;
A chemical vapor deposition apparatus provided with at least one of the gas blowing port and the stage unit, and a tilt mechanism for changing a distance between the gas blowing port and the stage unit. A chamber having a reaction chamber;
A gas blowout port disposed in the reaction chamber for blowing out a predetermined material gas;
A stage portion disposed in the reaction chamber so as to face the gas outlet and on which a semiconductor substrate is placed;
A gas supply control unit for supplying a material gas at a predetermined flow rate to the gas outlet;
An exhaust part for exhausting the reaction chamber,
The exhaust part is
A plurality of exhaust pipes connected to the reaction chamber;
A chemical vapor deposition apparatus comprising: an exhaust control unit for controlling an exhaust amount of each of the plurality of exhaust pipes. A chamber having a reaction chamber;
A gas blowout port disposed in the reaction chamber for blowing out a predetermined material gas;
A stage portion disposed in the reaction chamber so as to face the gas outlet and on which a semiconductor substrate is placed;
A chemical vapor deposition apparatus provided with at least one of the gas blowing port and the stage unit, and a tilt mechanism for changing a distance between the gas blowing port and the stage unit. A chamber having a reaction chamber;
A gas blowout port disposed in the reaction chamber for blowing out a predetermined material gas;
A stage portion disposed in the reaction chamber so as to face the gas outlet and on which a semiconductor substrate is placed;
A plurality of exhaust pipes connected to the reaction chamber;
A chemical vapor deposition apparatus comprising: an exhaust control unit for controlling an exhaust amount of each of the plurality of exhaust pipes.   5. The chemical vapor deposition apparatus according to claim 3, further comprising a gas supply control unit configured to supply a material gas having a predetermined flow rate to the gas outlet.   The chemical vapor deposition apparatus according to claim 1, wherein a plurality of the reaction chambers are provided in the chamber.

Images