JP3184682B2 - Plasma processing 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 plasma processing apparatus.

[0002]

2. Description of the Related Art Conventionally, in a semiconductor manufacturing process, a plasma processing apparatus for converting a gas into plasma and processing an object to be processed,
For example, in a plasma etching apparatus, as a means for improving the uniformity of etching of an object to be processed, for example, an integrated circuit formed on a semiconductor wafer, for example, a technique of optimizing a gas flow of a reaction gas is disclosed in Japanese Utility Model Laid-Open No. 59-189238. ,
JP-A-60-118236, JP-A-60-460
No. 29, for example. In these technologies, a plurality of gas outlets for ejecting a reactive gas in the direction of the semiconductor wafer are provided on an electrode opposite to an electrode on a mounting side on which a semiconductor wafer is mounted, and the position and size of the gas outlet are changed. Thus, the etching uniformity is set to be optimum.

As another means for improving the uniformity of etching, a focus ring around a semiconductor wafer is provided.
For example, there is a technology in which an insulating ring is arranged, and such a technique is disclosed in, for example, Japanese Patent Application Laid-Open No. 63-13333. This technique improves the uniformity of etching by locally adjusting the density of plasma generated on a semiconductor wafer.

[0004]

In the semiconductor industry, an object to be processed, for example, a semiconductor wafer having a larger diameter and an integrated circuit formed on the semiconductor wafer have been miniaturized. However, in the above-described technology for achieving uniform etching by changing the position and size of the gas outlet, since the gas is exhausted from the peripheral direction of the semiconductor wafer, the flow rate of the reaction gas ejected from the gas outlet is reduced. However, it becomes faster as it goes to the peripheral portion of the semiconductor wafer as compared with the center portion of the semiconductor wafer, and it is difficult to make the flow speed of the reaction gas uniform on the semiconductor wafer surface. Due to the non-uniform flow rate of the reaction gas, the density of plasma generated above the semiconductor surface is also non-uniform, making it difficult to achieve uniform etching. The non-uniformity of the plasma density is caused by the fact that when the semiconductor wafer has a large diameter, for example, a size of 12 inches or more, the etching rate at the center portion and the peripheral portion of the semiconductor wafer is further reduced as compared with a size of 6 inches or the like. There is a problem that unevenness becomes more and more unavoidable, and the yield of integrated circuits is reduced.

In the above-mentioned technology for improving the uniformity of etching by locally adjusting the density of plasma, a focus ring is arranged around a semiconductor wafer. The purpose is to confine the plasma inside the focus ring, and a plasma having a higher density is generated in the vicinity of the focus ring, that is, in the peripheral portion of the semiconductor wafer as compared with the center portion, and as described above, the semiconductor wafer becomes larger. As the process proceeds, the unevenness of the etching rate in the central portion and the peripheral portion of the semiconductor wafer becomes more and more, and there is a problem that the yield of the integrated circuit is reduced.

An object of the present invention is to generate a local plasma,
By moving the local plasma appropriately,
Plasma in the same state over the entire processing area
It was to provide a plasma processing apparatus capable of improving the uniformity of the plasma treatment of the workpiece.

[0007] In order to solve the above-mentioned problems, the first aspect of the present invention is as follows.
According to the aspect of the present invention, as described in claim 1, a plasma processing apparatus that mounts an object to be processed on a mounting table in an airtightly configured processing chamber, generates plasma, and processes the object to be processed. is arranged to face the mounting table, a high frequency said a local plasma generation means for applying a partial plasma to be processed, and a moving means for moving the local plasma generation means, the further loading table Apply power
A plasma processing apparatus including a high-frequency power supply and a power control unit is provided . According to such a configuration, the local plasma generation means causes the plasma to partially act on the processing target arranged opposite to the mounting table, and further the local plasma generation means is appropriately moved by the moving means, whereby the processing is performed. A uniform treatment can be performed by applying local plasma in the same state over the entire treatment range of the body. Since the plasma processing apparatus further includes a high-frequency power supply for applying high-frequency power to the mounting table and power control means , when the local plasma generation means moves, the power control means keeps generating the local plasma. By reducing the amount of high frequency power, only the action of plasma on the object can be suppressed. Further, a portion that acts on the object to be processed by the plasma generated by the local plasma generation unit is as described in claim 2 .
It is preferable that the distance is at least equal to or greater than the range of one integrated circuit formed on the object. Further, as described in claim 3, it is preferable that a gas supply pipe for supplying a plasma gas to the local plasma generating means is configured to be able to expand and contract following the movement of the plasma generating means.

According to a second aspect of the present invention to solve the above-mentioned problems, according to a second aspect of the present invention, an object to be processed is placed in an airtight processing chamber, and a plasma is generated to process the object. Is provided. The plasma processing method, as set forth in claim 4, the local plasma generation means for generating a station plant plasma, said a first step of positioning by moving on an integrated circuit of the untreated object to be processed, wherein a second step of generating the station plant plasma by local plasma generation means for the placed the object to be processed in the mounting table, by applying a high frequency electric power of electric energy to draw the local plasma before mounting table Performing a predetermined process by causing the local plasma to act on the unprocessed integrated circuit;
And a fourth step of reducing high-frequency power applied to the mounting table to an amount of electric power that is not drawn by the local plasma after the processing of the unprocessed integrated circuit is completed. a fifth step of repeating until raw integrated circuit is eliminated above, characterized in that said comprising a sixth step of stopping the station office plasma after all processing of the object to be processed has been completed. According to such a configuration, the local plasma generation means causes the plasma to partially act on the processing target arranged opposite to the mounting table, and further the local plasma generation means is appropriately moved by the moving means, whereby the processing is performed. A uniform treatment can be performed by applying local plasma in the same state over the entire treatment range of the body. In addition, when moving the local plasma generating means, it is not necessary to cut off the local plasma each time, so that high throughput processing is possible.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a plasma processing apparatus according to the present invention is applied to a plasma etching apparatus will be described below with reference to the accompanying drawings.

First, as shown in FIG. 1, a plasma etching apparatus 1 has a substantially cylindrical airtight processing chamber 2 made of a conductive material, for example, aluminum. At the bottom 3 in the processing chamber 2, a mounting table 4 for mounting an object to be processed, for example, a semiconductor wafer W, which is electrically insulated from the bottom 3, is arranged. The mounting table 4 includes a susceptor support 5 formed of a conductive member, for example, aluminum or the like, and a susceptor 7 as a lower electrode which is detachably provided on the susceptor with bolts 6.

The susceptor support 5 is provided with a coolant storage section for flowing and circulating a coolant, for example, liquid nitrogen, for example, a cooling jacket 8. The cooling jacket 8 is for supplying and discharging liquid nitrogen 9. Are connected.

The susceptor 7 has a disk shape having a convex portion at the center, and a fixing means for mounting and fixing the semiconductor wafer W on the mounting surface of the central convex portion, for example, an electrostatic device. A chuck 11 is provided. This electrostatic chuck 11
Is formed by sandwiching a conductive film 12 such as a copper foil between two polyimide films, for example.
Are connected to a DC high voltage source 14 via a voltage supply lead 13. Therefore, by applying a high voltage to the conductive film 12 from the DC high voltage source 14, a Coulomb force can be generated on the chuck surface, and the semiconductor wafer W can be suction-held on the mounting surface. Further, the susceptor 7 is provided with a heat transfer gas supply path 15 for supplying a heat transfer medium, for example, helium gas, on the back surface of the semiconductor wafer W.

The susceptor 7 is connected to a power supply rod 16 made of a hollow conductor by passing through the bottom 3 and the susceptor support 5.
The wiring 17 is connected to a first high frequency power supply 19 (RF) of a high frequency, for example, 380 KHz, 1 MHz, etc., via a blocking capacitor 18.

A temperature control heater 20 is provided between the susceptor 7 and the susceptor support 5, and a power supply for supplying power to the temperature control heater 20 is provided to the temperature control heater 20. A lead wire 21 is connected, and the power supply lead wire 21 is wired so as to penetrate through the power supply rod 16 and is connected to a power source 22.

Further, a temperature detecting means 23 for detecting the temperature of the semiconductor wafer W, for example, a laxtron or a thermocouple, is provided in the vicinity of the junction of the susceptor 7 with the electrostatic chuck 11. The detecting means 23 is connected to a controller 26 for controlling the entire apparatus via a filter 25 for removing high-frequency noise through a temperature detecting lead wire 24 transmitting a temperature signal detected by the temperature detecting means 23. Further, the controller 26 is configured to control the high-frequency power supply 19, the power supply 22, and the DC high-voltage power supply 14 according to a predetermined program.

An exhaust means, for example, a vacuum pump 28 is connected to the vicinity of the lower side of the processing chamber 2 through an exhaust pipe 27, and the inside of the processing chamber 2 can be evacuated to a desired reduced-pressure atmosphere. Further, a gas unit 30 is connected to a side wall of the processing chamber 2 via a supply pipe 29.
And it is configured to predetermined flow rate supplied into the processing chamber 2 with an inert gas such as nitrogen gas from the gas unit 30.

At a position facing the susceptor 7 across the semiconductor wafer W, a local plasma generating means 31 for locally or partially generating plasma with respect to the semiconductor wafer W is provided. The local plasma generating means 31 includes a pair of electrode plates 32a and 32b facing each other as shown in FIG.
a and 32b are fixed and a block 33 covers the upper and side portions. The material of the block 33 is formed of a conductive material such as aluminum, and its surface is subjected to a coating process such as an alumite process and is electrically grounded. An opening 40 is provided below the block 33 and between the pair of electrode plates 32a and 32b.

The block 33 includes the electrode plate 3.
A gas supply pipe 35 for transporting a plasma gas, for example, a gas such as CF 4, supplied from the gas unit 30 in order to blow out a gas to be turned into plasma from the gas discharge holes 34 formed in the gas outlets 2a and 32b. It is connected.
The gas supply pipe 35 is formed in a spiral shape in the processing chamber 2 as shown in FIG. Further, the block 33 includes a heating / cooling mechanism 3
6, a heating / cooling mechanism such as a Peltier element is provided, and the heating / cooling mechanism 36 includes a temperature controller 37
And the temperature controller 37 controls the controller 26
The temperature of the electrode plates 32a and 32b and the temperature of the block 33 itself can be set to predetermined temperatures based on the instruction signal of the above.

The pair of electrode plates 32a, 32b
, One is grounded and the other is via a blocking capacitor 38 at a high frequency, e.g.
MHz or the like and a second high frequency power supply 39 (RF).

Further, as shown in FIG. 1, the block 33 is provided with a fixing means 4 made of an insulating material, for example, ceramics, on a moving means 41 movable in the X, Y, and Z directions in the figure.
2 and the block 33 is connected to X,
It is configured to be movable in the Y and Z directions.

Next, the operation of the plasma etching apparatus 1 configured as described above will be described.

First, as shown in FIG. 1, the semiconductor wafer W is placed on the electrostatic chuck 11 in the processing chamber 2 under a reduced pressure atmosphere of a predetermined pressure, for example, 10 ⁻³ Torr or less by the vacuum pump 28, A high voltage is applied to the conductive film 12 by the high voltage source 14, and the semiconductor wafer W is held by Coulomb force generated in the electrostatic chuck 11.

Next, the control unit 26 monitors the temperature information from the thermocouple 23 according to a program stored in advance, and controls the amount of power of the power source 22 that supplies power to the heater 20 and the amount of refrigerant supplied to the cooling jacket 8. The temperature of the semiconductor wafer W is set to a predetermined temperature, for example, −20 ° C. or lower while controlling the supply amount of the refrigerant for supplying the liquid nitrogen 9 via the discharge path 10.

Thereafter, the local plasma generating means 31 is moved by the moving means 41 in the X, Y, and Z directions in the figure and set at a predetermined position. The predetermined position is, for example, a one-chip position 44 of the integrated circuit element 43 formed on the semiconductor wafer W shown in FIG.

Next, the controller 26 instructs the gas unit 30 on the gas supply amount, transports the plasma gas from the gas unit 30 to the block 33 via the gas supply pipe 35, Spouts flow rate. Then, the controller 26 turns on the second high-frequency power supply 39 and sets the electrode plate 32
A high frequency power is applied to the electrodes a and 32b to generate a plasma 45 between the electrode plates 32a and 32b as shown in FIG. Thereafter, as shown in FIG. 4B, the controller 26 instructs the first high frequency power supply 19 to apply a predetermined amount of high frequency power to the susceptor 7. By this application, the electrode plate 3
The plasma 45 generated between 2a and 32b is drawn out onto the integrated circuit element 43, and is subjected to an etching process using active species in the plasma 45. The electrode plates 32a, 32b
The amount of plasma generated between them varies depending on the magnitude of the high-frequency power applied to the susceptor 7.

The procedure of these processes is, for example, as shown in FIG. 5, started by positioning the integrated circuit element to be processed, turning on the second high-frequency power source, and turning on the electrode plate 32.
a, the first high-frequency power supply is turned on, or the power value is increased to an amount of electric power for drawing the plasma 45 generated between the electrode plates 32a, 32b.
For processing a predetermined integrated circuit on the semiconductor wafer W, the first high-frequency power source is turned off or the power value is reduced to an amount of power that does not draw the plasma 45 generated between the electrode plates 32a and 32b. It is determined whether or not the processing of all the integrated circuits has been completed, and the processing is performed if the processing has been completed. The local plasma generating means 31 is moved to the next unprocessed integrated circuit by the moving means 41 in order from the processing. Repeatedly, the second high-frequency power supply is turned off, the plasma 45 generated between the electrode plates 32a and 32b is stopped, the processing is completed, and the processing is replaced with the next semiconductor wafer.

When the local plasma generating means 31 is moved to the next unprocessed integrated circuit by the moving means 41 in the processing described above, the processing is started from the chip position 44 as shown in FIG. If the moving means 41 repeats the rightward movement 47 and the leftward movement 48 in every other row in the order of adjacent chips, the processing throughput is further improved.

The effect of the present embodiment having the above-described configuration will be described.

The local plasma generating means 31 for applying plasma to the local or part of the semiconductor wafer W is moved by the moving means 41 to generate uniform plasma in the same state for each local or part over the entire processing range of the semiconductor wafer W. Since the movement can be performed by the moving means, the processing error of the semiconductor wafer within the processing range of the processing target can be suppressed, the uniformity of the plasma processing of the processing target can be improved, and the yield of the processing target can be improved. be able to. Further, if the plasma generated by the local plasma generating means 31 is made uniform and uniform, it is possible to cope with a large-sized semiconductor wafer W having a size of 8 inches or more without changing the plasma source. Furthermore, the amount of plasma generated by the local plasma generating means 31 can be adjusted by the amount of power of the first high-frequency power supply 19 for applying high-frequency power to the susceptor 7 serving as an extraction electrode, so that the processing of the semiconductor wafer can be repeated. In this case, for example, first, an etching process is performed at an etching rate of 2000 ° and then 500 °.
, It is possible to easily perform the overlapping processing.

Next, the second embodiment will be described. The same parts as those in the first embodiment are denoted by the same reference numerals and description thereof will be omitted. As shown in FIG. 6, a plurality of blocks 33 of the local plasma
Thus, the semiconductor wafer W is moved in one direction, for example, in the X direction in the figure. With this configuration, a plurality of integrated circuits formed on the semiconductor wafer W can be simultaneously subjected to plasma processing, and the processing throughput can be improved.

Next, the third embodiment will be described. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description will be omitted. As shown in FIG. 7, the local plasma generating means 31 is not a parallel plate type, but a second high frequency power supply 39.
A rod-shaped electrode 32a as an application side from the electrode, and a cylindrical electrode 32b as a ground side around the rod-shaped electrode 32a
And a gas ejection hole 34 for introducing a plasma gas is formed in the electrode 32b. With such a configuration, processing can be performed even if the active area of the integrated circuit or plasma formed on the semiconductor wafer W is circular.

Next, the fourth embodiment will be described. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description will be omitted. As shown in FIG. 8, the local plasma generating means 31 has a spiral antenna 71 disposed above a member 70 formed of a cylindrical insulating material, for example, quartz glass or ceramics. Power is supplied from the second high-frequency power supply 39, and a gas ejection hole 34 for introducing a plasma gas is formed around the antenna 71 and above the member 70. With such a configuration, when the local plasma generating units 31 are provided side by side, since the plasma gas is not introduced from the side of the member 70, the local plasma generating units 31 can be densely provided side by side without any gap. In addition, the semiconductor wafer can be uniformly processed to cause processing unevenness.

Next, a description will be given of a fifth embodiment. The same parts as those of the first embodiment are denoted by the same reference numerals, and the description is omitted. As shown in FIG. 9, the local plasma generating means 31 is arranged by winding a spiral antenna 71 around a member 70 formed of a bell-shaped insulating material, for example, quartz glass or ceramics.
And a high-frequency power supply 39 for supplying high-frequency electric power to both ends of the gas-injecting hole 3 for introducing a plasma gas at a location provided above the bell-shaped insulating material.
4 are drilled. With this configuration,
It is not necessary to provide a plurality of gas ejection holes 34 for introducing a plasma gas, and the space of the apparatus can be simplified.

In the embodiment, the case where the semiconductor wafer is used as the object to be processed has been described. However, the present invention is not limited to this.
For example, an LCD substrate may be used, and a Peltier element is used as a heating / cooling mechanism, but liquid helium or the like may be used as a cooling mechanism, or a heater may be used as a heating mechanism . Furthermore, the mounting table on which the object to be processed is mounted is fixed, and the local plasma generating means is moved and moved by the moving means, but the local plasma generating means is fixed and the mounting table for mounting the object to be processed is moved by the moving means. You may move . Also,
The gas ejection holes of the local plasma generating means are provided on both of the pair of electrode plates, but only the other electrode plate may be provided. But it is good. Although one of the electrode plates of the local plasma generating means is connected to the ground side of a high frequency power supply (RF), a high frequency power having a different phase, for example, 180 degrees may be applied. Furthermore, although the local plasma generating means is moved by the moving means, a plurality of local plasma generating means may be fixedly arranged over the entire surface of the object to be processed and the high frequency power may be independently or independently communicated.

Further, in the embodiment, as an example, an example in which the plasma processing apparatus according to the present invention is applied to a plasma etching apparatus has been described. However, the present invention is not limited to such an apparatus and may be applied to a CVD apparatus, an ashing apparatus, an LCD apparatus, and the like. The present invention can also be applied to an apparatus that generates a plasma and processes an object to be processed.

[0036]

According to the present invention, since uniform plasma of the same state which is partially generated over the entire processing range of the object to be processed is sequentially applied, an error in the processing within the processing range of the object is suppressed. Thus, the uniformity of the plasma processing of the object to be processed can be improved, and the yield of the object to be processed can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a plasma etching apparatus to which a first embodiment according to the present invention is applied.

FIG. 2 is a partial perspective view of the local plasma generating means of FIG.

FIG. 3 is a schematic view of an object to be processed for explaining the operation of moving and processing the local plasma generating means of FIG. 1 by the moving means.

FIG. 4 is a partial cross-sectional view for explaining the operation of the local plasma generating means of FIG.

FIG. 5 is a flowchart for explaining the operation of the local plasma generating means of FIG. 1;

FIG. 6 is a partial perspective view of a local plasma generating means for explaining a second embodiment.

FIG. 7 is a partial perspective view of a local plasma generating means for explaining a third embodiment.

FIG. 8 is a partial perspective view of a local plasma generating means for explaining a fourth embodiment.

FIG. 9 is a partial perspective view of a local plasma generating means for explaining a fifth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plasma etching apparatus (plasma processing apparatus) 2 Processing chamber 4 Mounting table 19 First high frequency power supply 26 Controller 31 Local plasma generation means 33 Block 34 Gas ejection hole 39 Second high frequency power supply W Workpiece (semiconductor wafer)

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 21/3065 C23F 4/00 H05H 1/46

Claims (4)

(57) [Claims] 1. A plasma processing apparatus for mounting an object to be processed on a mounting table in an airtightly configured processing chamber, generating plasma, and processing the object, wherein the plasma processing apparatus is disposed to face the mounting table. wherein comprising a local plasma generation means for applying a partial plasma workpiece, and moving means for moving the local plasma generation means, further the placement
A high-frequency power supply for applying high-frequency power to the table and power control means
Plasma processing apparatus characterized by comprising. 2. The plasma processing apparatus according to claim 1, wherein a portion of the plasma generated by the local plasma generating means, which acts on the object, is at least as large as an integrated circuit formed on the object. Plasma processing equipment. 3. A process according to claim 1, wherein the local plasma generation gas supply pipe for supplying a plasma gas to the means is characterized in that a telescopic and follow the movement of the plasma generation means
Or the plasma processing apparatus according to 2. Wherein the object to be processed is placed on a mounting table in a processing chamber configured airtight, there is better plasma processing to generate plasma for processing the object to be processed, the local plasma to generate a station plant plasma the generation means, wherein a first step of positioning moves onto untreated integrated circuits of the object to be processed, a second step of generating the station plant plasma by the local plasma generation means, mounted on the mounting table A third step of applying a high-frequency power of an amount of electric power for drawing the local plasma to the mounting table to the processing target to perform predetermined processing on the unprocessed integrated circuit; A fourth step of reducing the high-frequency power applied to the mounting table to an amount of electric power that is not attracted by the local plasma after the end of the processing for the above, and the unprocessed integrated circuit is eliminated from the first to fourth steps on the object to be processed. Ma Fifth step and a plasma processing method characterized in that it consists of, a sixth step of stopping the station office plasma after all processing is completed for the object to be processed repeating.