JP3801130B2 - Semiconductor device manufacturing method and manufacturing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention collects and removes particulate impurities (referred to as particles in this specification) such as dust generated in a vacuum chamber used in a dry process performed in the manufacturing process of a semiconductor device by using static electricity. The present invention relates to a semiconductor device manufacturing method and a manufacturing apparatus.
[0002]
[Prior art]
Semiconductor devices have been miniaturized with the progress of dry process technology using plasma discharge such as plasma etching, reactive ion etching (RIE), plasma enhanced CVD (PECVD), and bias sputtering. Along with the progress of miniaturization, pattern defects caused by the presence of fine particles in a vacuum chamber used in a dry process have become a major factor in reducing the product yield. Such fine particles are generated by wear of the sliding portion of the handling device when moving the semiconductor wafer in the vacuum chamber, erosion of a jig or the like by plasma processing, generation of a reaction product by dry etching, or the like.
[0003]
To deal with this problem, internal processing in the vacuum chamber, process gas cleaning, optimization of the vacuum chamber cleaning interval, plasma cleaning, improvement of the wafer placement method, and mechanical brush cleaning such as a scrubber after the process is added Various measures are taken such as. However, the actual situation is that the reduction of the product yield due to the particles is still not sufficiently suppressed.
[0004]
[Patent Document 1]
JP-A-8-80453
[0005]
[Patent Document 2]
JP-A-10-233387
[0006]
[Problems to be solved by the invention]
The present invention has been made to solve the above problems, and its purpose is to reduce the product yield by attaching fine particles in the vacuum chamber to the surface of the semiconductor wafer in the dry process during the manufacturing process of the semiconductor device. An object of the present invention is to provide a manufacturing method and a manufacturing apparatus that can reduce problems caused.
[0007]
[Means for Solving the Problems]
The invention described in claim 1 for achieving the above object is a method for manufacturing a semiconductor device, comprising the following six steps.
(1). A first dust collection mechanism constituted by an electrostatic chuck is inserted into the process chamber from a dust collection chamber connected to the process chamber via a load lock valve in a state where a voltage is supplied. First step.
(2). A second step of holding the first dust collecting mechanism inserted into the process chamber in the first step for a predetermined time while supplying a voltage.
(3). A third step of closing the load lock valve by returning the first dust collecting mechanism to the dust collecting chamber in a state where a voltage is supplied after completion of the second step.
(4) . A fourth step of stopping the voltage supply to the first dust collecting mechanism and inserting the first dust collecting mechanism into a second dust collecting mechanism constituted by an electrostatic chuck after finishing the third step .
(5) . A fifth step of supplying a voltage to the second dust collecting mechanism for a predetermined time after the insertion;
(6) . A sixth step of carrying out the first dust collection mechanism to the outside of the second dust collection mechanism in a state where a voltage is supplied to the second dust collection mechanism after the fifth step is completed.
[0008]
According to such a method, by performing the first, second, and third steps, particles floating or adhering in the process chamber are collected by the electrostatic chuck and taken away to the dust collection chamber. There is an effect that the inside particles are reduced and the cleanliness is improved. Furthermore, by performing the fourth and subsequent steps, the particles collected in the process chamber can be collected again by the second dust collection mechanism. Since the first dust collecting mechanism is cleaned by removing particles, the inside of the dust collecting chamber can be prepared for the next particle dust collecting operation in the process chamber without returning to the atmospheric pressure.
[0009]
The invention according to claim 2 is a manufacturing apparatus for performing the method according to claim 1, and comprises a dust collection chamber connected to the process chamber via a load lock valve, and an electrostatic chuck. A dust collection mechanism, a handling arm that is installed in the dust collection chamber, holds the first dust collection mechanism and conveys the process chamber and the dust collection chamber, and is installed in the dust collection chamber, A second dust collecting mechanism comprising an electrostatic chuck that houses the first dust collecting mechanism conveyed by a handling arm and collects particles adhering to the first dust collecting mechanism; and the first and second dust collecting mechanisms A semiconductor device manufacturing apparatus comprising: a DC power supply that switches and supplies a DC voltage to a dust collecting mechanism.
[0010]
If a semiconductor device is manufactured using such an apparatus, the same effect as that of the first aspect of the invention can be obtained.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a schematic configuration of the manufacturing apparatus of the present embodiment. This apparatus includes a process chamber 1, a dust collection chamber 2, and a preparation chamber 3. The dust collection chamber 2 and the preparation chamber 3 are provided adjacent to the process chamber 1 via load lock valves 4 and 5, respectively. Each chamber can be evacuated to a required degree of vacuum by a vacuum pump (not shown).
[0020]
The process chamber 1 is a chamber in which a dry process such as thin film formation and dry etching is performed on a semiconductor wafer. The preparation chamber 3 is used for loading and unloading a semiconductor wafer to be processed into and out of the process chamber 1 maintained in a vacuum state, and for pre-processing and post-processing of the semiconductor wafer. Function as. The inside is usually provided with a semiconductor wafer transfer device such as an atmospheric handling arm (not shown). A gate 6 is provided between the outside air.
[0021]
The dust collection chamber 2 is a chamber for storing dust collection equipment necessary for adsorbing and removing particles floating and adhering in the process chamber 1 using electrostatic force. The dust collection device includes a first dust collection mechanism 7 installed in the dust collection chamber 2, a second dust collection mechanism 8, a handling arm 9, a DC power supply device 10 installed outside the dust collection chamber 2, and There is. The dust collection chamber 2 includes a gate 11 between the outside air.
[0022]
The first dust collection mechanism 7 is a mechanism that is inserted into the process chamber 1 and collects particles existing in the process chamber 1 using electrostatic force. As shown in FIG. 2, the configuration is constituted by three electrostatic chucks 7a, 7b and 7c which are parallel to each other and an insulating support plate 7d which supports them. The number of electrostatic chucks is not limited to three. However, in order to increase the dust collection effect, it is preferable to increase the number and to make the surface area of each electrostatic chuck wide.
[0023]
An electrostatic chuck is usually used to fix a semiconductor wafer using electrostatic force, but polarizes particles present in the vicinity by a strong electric field that is generated, and is attracted and collected by electrostatic force. be able to. The electrostatic chuck includes a monopolar type and a bipolar type. FIG. 3 shows a cross section of the monopolar electrostatic chuck 13 and the particle collecting principle. The monopolar electrostatic chuck 13 has a configuration in which a single foil-like or film-like electrode 13b is embedded in an insulator 13a such as ceramics or a dielectric sheet.
[0024]
Such a unipolar electrostatic chuck 13 is installed in, for example, the process chamber 1 and a DC high voltage is applied between the internal electrode 13b and the grounded process chamber 1 so that the internal electrode is positive, for example. . Then, the insulator 13a is polarized to generate a positive polarization charge on the surface, and a strong electric field E is generated from the electrode 13b toward the inner wall of the process chamber 1. When the particle 14 is present in this electric field, the particle 14 is polarized by the electric field E. That is, if the particle 14 is a dielectric, a negative charge is induced by dielectric polarization, and if it is a conductor, a negative charge is induced on the side facing the electrode 13b and a positive charge is induced on the opposite side. The generated negative charge has an attractive force toward the electrode 13b due to the electric field E, and conversely, the positive charge has a repulsive force toward the inner wall of the process chamber 1. However, since the electric field lines due to the electric field E spread from the electrode 13b toward the inner wall of the process chamber 1, the electric field strength becomes weaker as the distance from the electrode 13b increases. For this reason, the attractive force acting on the negative charge is superior to the repulsive force acting on the positive charge, and the particle 14 moves toward the electrode 13b, and finally reaches the surface of the monopolar electrostatic chuck 13 to reach the insulator. It is adsorbed and collected by electrostatic force between the positive polarization charge on the surface of 13a.
[0025]
FIG. 4 shows a cross section of the bipolar electrostatic chuck 15 and the particle collecting principle. The bipolar electrostatic chuck 15 has a structure in which two or three or more electrodes 15b are embedded in an insulator 15a. A high DC voltage having a different polarity is applied to each electrode 15b. In this case, the electric lines of force of the generated electric field E are as shown by the dotted lines in the figure, and a strong electric field E directed from the positive electrode to the negative electrode is generated. The particles 16 existing in the electric field E are polarized by the electric field E to generate negative charges on the positive electrode side and positive charges on the negative electrode side. The generated positive charge is moved toward the negative electrode side, and the negative charge is moved toward the surface of the bipolar electrostatic chuck 15 by receiving an attractive force toward the positive electrode side by the electric field E, and finally the bipolar electrostatic chuck. It reaches the surface of 15 and is adsorbed and collected by electrostatic force.
[0026]
The first dust collecting mechanism 7 constituted by such a monopolar electrostatic chuck 13 and a bipolar electrostatic chuck 15 is fixed to the tip grip portion of the handling arm 9 and conveyed. The electrostatic chucks 7 a, 7 b, and 7 c constituting the first dust collecting mechanism 7 are supplied with power from the DC power supply device 10 through the flexible cable 12.
[0027]
The second dust collecting mechanism 8 is for re-collecting and accumulating particles collected by the first dust collecting mechanism 7, and includes six parallel electrostatic chucks 8a to 8f as shown in FIG. It comprises an insulating support plate 8g that supports them. As will be described later, the electrostatic chucks 8a to 8f are provided between the electrostatic chucks 7a, 7b and 7c of the first dust collecting mechanism 7 and between the electrostatic chucks 8a and 8b of the second dust collecting mechanism 8, respectively. In the meantime, it is attached to the support plate 8g so as to fit between 8e and 8f with a certain gap without contact.
[0028]
The handling arm 9 is an articulated arm, and can transport the first dust collecting mechanism 7 fixed to the tip grip portion in the horizontal plane direction and the vertical direction. The tip grip portion also has a degree of freedom for horizontally rotating the first dust collecting mechanism 7.
[0029]
The DC power supply device 10 includes a transformer whose primary side is connected to a low-voltage AC power source and a rectifier that rectifies the AC high voltage on the secondary side of the transformer, and generates a high-voltage DC voltage at the output. . The generated DC high voltage is selectively supplied to the first dust collection mechanism 7 or the second dust collection mechanism 8. When the electrostatic chuck to be used is a bipolar type, positive, negative and both voltages are supplied. However, when the electrostatic chuck is used, only a positive voltage is supplied and the negative side is grounded. Connected to the dust collection chamber 2.
[0030]
Next, an operation of collecting particles in the process chamber 1 under such an apparatus configuration will be described.
The dust collection operation of the particles in the process chamber 1 is performed before the semiconductor wafer to be processed is carried into the process chamber 1. First, the degree of vacuum in the dust collection chamber 2 is lowered to the same level as in the process chamber 1 by using a vacuum pump (not shown). With the DC power supply 10 turned off, the first dust collecting mechanism 7 is held at the standby position by the handling arm 9. This standby position is a position that does not overlap with the second dust collecting mechanism 8.
[0031]
After the degree of vacuum is sufficiently lowered, the DC power supply device 10 is turned on to supply the DC high voltage generated through the flexible cable 12 to the first dust collecting mechanism 7. Next, the load lock valve 4 between the dust collection chamber 2 and the process chamber 1 is opened. Then, the first dust collecting mechanism 7 is inserted into the process chamber 1 by the handling arm 9 in a state where power is supplied. The state after insertion is shown in FIGS. 6 shows a planar state in the apparatus, and FIG. 7 shows a state in which the inside of the process chamber 1 is viewed from the side. Reference numerals 17a and 17b in FIG. 7 denote jigs and materials (hereinafter referred to as jigs) such as an electrode for plasma discharge, a semiconductor wafer support holder, a target for sputtering, and the like fixed to the inner wall of the process chamber 1. Represents. The electrostatic chucks 7a and 7b of the first dust collecting mechanism 7 are designed in shape and mounting position so that they can be positioned by the handling arm 9 at positions facing the jigs 17a and 17b with a narrow gap, respectively. ing.
[0032]
If the first dust collecting mechanism 7 is kept in this state for a while while being fed, the particles existing in the electric field generated by the electrostatic chucks 7a, 7b, 7c are polarized in accordance with the particle collecting principle described above, and electrostatic Adsorbed and collected on the surfaces of the chucks 7a, 7b, 7c. In this case, in the case where the electrostatic chucks 7a and 7c are the monopolar electrostatic chuck 13, a mechanism for charging and collecting particles in addition to the polarization is collected. That is, as shown in FIG. 8, when a positive voltage is applied to the electrode 13b of the monopolar electrostatic chuck 13 and the jig 17a is grounded, a negative charge is generated on the surface of the jig 17a. . The particles 18 attached to the surface of the jig 17a receive a negative charge from the jig 17a and are negatively charged. The negatively charged particles 18 receive a force directed toward the electrode 13b by a strong electric field E directed from the electrode 13b toward the jig 17a. When this force exceeds the adhesion force of the particles 18 to the surface of the jig 17a, the particles 18 move away from the surface of the jig 17a and are negatively applied to the surface of the insulator 13a of the monopolar electrostatic chuck 13. Attached and collected in a charged state.
[0033]
As described above, by holding the dust collection mechanism 7 with a high DC voltage for a predetermined time, floating particles in the process chamber 1 and particles adhering to the surfaces of the jigs 17a and 17b are removed. 7 is adsorbed and collected on the surface.
[0034]
When the particles are thus collected, the first dust collecting mechanism 7 is returned to the original standby position in the dust collecting chamber 2 by the handling arm 9 while the voltage is applied. Then, by closing the load lock valve 4, the particle dust collection operation in the process chamber 1 is completed. Through such a series of steps, the particles in the process chamber 1 are collected and carried into the dust collection chamber 2, and the cleanliness in the process chamber 1 is improved.
[0035]
Thereafter, the load lock valve 5 is opened and a semiconductor wafer to be processed is loaded into the process chamber 1 from the preparation chamber 3, and the intended dry process is performed in a clean atmosphere.
[0036]
Next, the subsequent treatment of the first dust collection mechanism 7 returned to the standby position in the dust collection chamber 2 will be described. After the load lock valve 4 is closed, the DC power supply 10 is turned off to stop the voltage supply to the first dust collecting mechanism 7. The amount of particles present in the process chamber 1 is usually very small. Therefore, the amount of particles collected by the first dust collection mechanism 7 by one dust collection operation in the process chamber 1 is also small. For this reason, the first dust collecting mechanism 7 returned to the dust collecting chamber 2 is kept waiting at the standby position as it is, and the particle dust collecting work in the process chamber 1 is again performed in accordance with the operation procedure described above before the processing of the next semiconductor wafer. Can also be performed. Such dust collection operation is repeated several times, and the dust collection chamber 2 is returned to atmospheric pressure when the amount of particles attached to the first dust collection mechanism 7 reaches a certain level. A working method is also possible in which the gate 11 between the outside air is opened and the first dust collecting mechanism 7 is replaced with another clean dust collecting mechanism to prepare for the next dust collecting work.
[0037]
However, it is preferable to remove the adhering particles from the first dust collecting mechanism 7 in the dust collecting chamber 2 every time the dust collecting work is finished, and to prepare for the next dust collecting work. In order to realize this, after returning to the standby position in the dust collection chamber 2 and stopping the voltage supply, the first dust collection mechanism 7 is inserted into the second dust collection mechanism 8 by the handling arm 9. The state after insertion is shown in FIGS. FIG. 9 shows a planar state in the apparatus, and FIG. 10 shows a state viewed from the side when the first dust collecting mechanism 7 is inserted into the second dust collecting mechanism 8. The three electrostatic chucks 7a, 7b, 7c of the first dust collecting mechanism 7 are held between the electrostatic chucks 8a to 8f of the second dust collecting mechanism 8 with a slight gap therebetween.
[0038]
In the state of positioning as described above, power is supplied from the DC power supply device 10 to the second dust collecting mechanism 8. Then, the particles collected on the surface of the first dust collecting mechanism 7 from which the power supply has been cut off are polarized by the electric field generated by the electrostatic chucks 8a to 8f of the second dust collecting mechanism 8, and the particle collecting described above. According to the principle, the particles are collected on the surfaces of the electrostatic chucks 8a to 8f of the second dust collecting mechanism 8. At this time, when the electrostatic chucks 8 a to 8 f are the monopolar electrostatic chucks 13, the charges previously negatively charged in the process chamber 1 and collected on the surface of the first dust collecting mechanism 7 are charged. A mechanism in which particles are attracted to and collected on the surfaces of the electrostatic chucks 8a to 8f by an electric field generated by the electrostatic chucks 8a to 8f to which a positive voltage is applied.
[0039]
Thus, the particles adhering to the surface of the first dust collecting mechanism 7 are collected again on the surface of the second dust collecting mechanism 8. When the re-collection is completed, the first dust collecting mechanism 7 from which the particles have been removed is taken out of the second dust collecting mechanism 8 and returned to the initial standby position to perform the next dust collecting operation in the process chamber 1. Prepare for. Such a series of dust collection operations are repeated a plurality of times, and when the amount of particles collected by the second dust collection mechanism 8 increases, the inside of the dust collection chamber 1 is returned to atmospheric pressure and the gate 11 between the outside air And the second dust collecting mechanism 8 is replaced with another clean dust collecting mechanism. The removed dust collection mechanism is cleaned by chemical cleaning or mechanical brush cleaning to prepare for the next replacement.
[0040]
As described above, according to the present embodiment, the first dust collecting mechanism 7 constituted by the electrostatic chucks 7a, 7b, and 7c is held in the process chamber 1 for a predetermined time while being supplied with power. Particles floating or adhering inside are collected. The collected particles are carried to the dust collection chamber 2 by the handling arm 9 while attached to the first dust collection mechanism 7. As a result, the number of particles in the process chamber 1 is reduced, the cleanliness is improved, and a dry process with few particles can be performed.
[0041]
Further, particles that adhere to the first dust collection mechanism 7 and are carried to the dust collection chamber 2 are transferred to the second dust collection mechanism 8 by re-collection. Therefore, the first dust collection mechanism 7 returns to a clean state after the particles are removed, and can be prepared for the next dust collection operation. As a result, the dust collection operation in the process chamber 1 can be performed a plurality of times while the vacuum degree of the dust collection chamber 2 is maintained, and the workability is improved.
[Brief description of the drawings]
FIG. 1 is an internal plan view of a manufacturing apparatus according to an embodiment of the present invention in a standby state.
FIG. 2 is a perspective view of a first dust collecting mechanism 7;
FIG. 3 is a diagram showing a configuration of a monopolar electrostatic chuck 13 and a particle collecting principle.
FIG. 4 is a diagram showing the configuration of a bipolar electrostatic chuck 15 and the principle of particle collection.
FIG. 5 is a perspective view of a second dust collecting mechanism 8;
FIG. 6 is an internal plan view of the dust collection state in the process chamber 1;
7 is a side view of the inside of the process chamber 1 in a particle dust collection state in the process chamber 1. FIG.
FIG. 8 is a diagram showing the principle of collecting charged particles by the monopolar electrostatic chuck 13;
9 is a plan view of the inside of the manufacturing apparatus in a state where particles adhering to the first dust collecting mechanism 7 are transferred to the second dust collecting mechanism 8. FIG.
10 is a side view showing a positional relationship between the first dust collecting mechanism 7 and the second dust collecting mechanism 8 in a state where particles adhering to the first dust collecting mechanism 7 are transferred to the second dust collecting mechanism 8. FIG.
[Explanation of symbols]
In the drawings, 1 is a process chamber, 2 is a dust collection chamber, 3 is a preparation chamber, 4 and 5 are load lock valves, 7 is a first dust collection mechanism, 7a to 7c and 8a to 8f are electrostatic chucks, and 8 is The second dust collecting mechanism, 9 is a handling arm, 10 is a DC power supply, 13 is a monopolar electrostatic chuck, and 15 is a bipolar electrostatic chuck.

Claims (2)

A method for manufacturing a semiconductor device, comprising:
A first dust collection mechanism constituted by an electrostatic chuck is inserted into the process chamber from the inside of the dust collection chamber connected to the process chamber via a load lock valve in a state in which a voltage is supplied. A first step of
A second step of holding the first dust collecting mechanism inserted into the process chamber by the first step for a predetermined time while supplying a voltage;
After the completion of the second step, a third step of closing the load lock valve by returning the first dust collecting mechanism to the dust collecting chamber while supplying a voltage;
After finishing the first step, the second step, and the third step, the voltage supply to the first dust collecting mechanism is stopped and the first dust collecting mechanism is configured as a second dust collecting mechanism constituted by an electrostatic chuck. A fourth step of insertion;
A fifth step of supplying a voltage to the second dust collecting mechanism for a predetermined time after insertion;
And a sixth step of carrying out the first dust collecting mechanism to the outside of the second dust collecting mechanism in a state in which a voltage is supplied to the second dust collecting mechanism after the fifth step is completed. A method for manufacturing a semiconductor device. A manufacturing apparatus for performing the method according to claim 1,
A dust collection chamber connected to the process chamber via a load lock valve;
A first dust collecting mechanism constituted by an electrostatic chuck;
A handling arm which is installed in the dust collection chamber and holds the first dust collection mechanism and conveys the process chamber and the dust collection chamber;
A second dust collector configured by an electrostatic chuck that is installed in the dust collection chamber and accommodates the first dust collection mechanism conveyed by the handling arm and collects particles adhering to the first dust collection mechanism. Well,
A semiconductor device manufacturing apparatus comprising: a DC power supply device that switches and supplies a DC voltage to the first and second dust collecting mechanisms.

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