JPS6383258A - Sputtering device - Google Patents

Abstract

PURPOSE:To enable easy detection of a service life of a target by determining the integrated electric power supplied to the target from the electric power supplied to the target and time with a sputtering device. CONSTITUTION:The integrated electric power set value which is the basis of the target life is preliminarily inputted and stored into a target life detector 33 by an integrated electric power set value inputting device 32 at the time of depositing the material of the target by sputtering using gaseous Ar ions on the surface of a semiconductor wafer 8 in a sputtering treatment chamber 5. The electric power consumption by an integrated electric power measuring instrument 31 for the target under work is then supplied to the above-mentioned device 33 and the sputtering operation is continued upon judgement that the target 11 has still a life if said value is larger than the set value. The operation is stopped on judgement that the life of the target runs out if said value is larger. The degradation in the quality of the vapor deposited film of the target material by the sputtering on the wafer 8 is thus prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Industrial Application Field) The present invention relates to a sputtering apparatus, and particularly to a sputtering apparatus equipped with a target life detection mechanism.

(Prior Art) In recent years, sputtering apparatuses have been widely used as thin film forming apparatuses, which sputter a target with high-energy particles such as ion particles and attach the particles flying from the target to a substrate, such as a semiconductor wafer, to form a thin film. There is.

In such sputtering equipment, as the amount of sputtering increases, the target gradually wears out, and the shape of the sputtering surface of the target changes, making it impossible to perform normal film deposition, and making it impossible to obtain the initial film thickness value. Regular replacement of targets is required.

Conventionally, methods for determining when to replace a target in a sputtering device have determined the target life based on the number of substrates processed, such as the number of substrates introduced into the sputtering device and the number of times a shutter installed in the sputtering device is opened and closed. I was looking for a time to replace the target.

(Problem to be Solved by the Invention) However, with the target life detection means that depends on the number of substrates processed as described above, it is difficult to take into account the amount of wear of the target during the plasma discharge time when the shutter is closed, so-called idling operation. In addition, if sputtering conditions such as power supply to the target or sputtering time are changed during work, the correlation between the number of wafers processed and the state of target wear will no longer match, making it difficult to accurately determine the target lifespan. The problem was that it could not be detected. Furthermore, due to this problem, even if the target is in a usable condition, it must be replaced with sufficient time to prevent the occurrence of defective products, which is disadvantageous in terms of economy.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a sputtering apparatus that can accurately detect target life even when sputtering is performed under any sputtering conditions.

[Structure of the Invention] (Means for Solving the Problems) According to the present invention, in a sputtering apparatus that forms a thin film on a substrate using particles sputtered by a target, the amount of power supplied to the target and the target There is obtained a sputtering apparatus characterized in that it includes means for detecting the lifespan of Targetera I from the integrated power value and the power supply time to Targetera I.

The plasma discharge time is suitable as the power supply time.

(Function) In the present invention, since the valve stand of the target is detected from the integrated power value of the amount of power supplied to the target and the power supply time, which are sputtering conditions, it is possible to always accurately target the target regardless of changes in the sputtering conditions. Lifespan can be detected.

(Example) An example in which the present invention is applied to a magnetron sputtering apparatus will be described below.

Inside the cylindrical reaction tank 1, which maintains airtightness, there are cylindrical wafer processing chambers, such as a wafer insertion/removal chamber 2, an etching processing chamber 3, a wafer heating chamber 4, a first sputter processing chamber 5, and a second sputter processing chamber. The processing chambers 6 are arranged in parallel in the order of semiconductor wafer processing steps. Then, the semiconductor wafer is inserted into the reaction tank 1 from the wafer insertion/removal chamber 2 by a wafer transfer device (not shown), and is sequentially sent between the processing chambers and subjected to a predetermined process. From there, semiconductor wafers that have been processed are sequentially taken out, and new semiconductor wafers are inserted.

A more specific configuration of the sputtering chamber will be described with reference to FIG. 2.

A sputter electrode section 7 is provided in the sputter processing chamber 5 in parallel to the inner wall surface of the reaction chamber 1, and a semiconductor wafer 8 is placed facing the sputter electrode section 7.

A cylindrical partition wall 9 extends from the inner wall of the reaction tank 1 on the back side of the sputter electrode part 7 so as to cover the sputter electrode part 7 in the side direction. A gap 10 is provided between them so that the atmospheric gas within the reaction tank 1 can flow between the respective processing chambers.

The sputter electrode section 7 includes a target 11 having an inverted conical ring-shaped sputtering surface connected to a power supply 30, a disc-shaped one pole, for example, an N magnetic pole 12, arranged at the center of the target 11, and an outer peripheral part of the target 11. For example, an S magnetic pole 13 is attached to the front edge of the partition wall 9 so as to surround it, and these magnetic poles 12 and 13 form an arc-shaped magnetic field A in the vicinity of the sputtering surface of the target 11. This arc-shaped magnetic field A acts to temporarily confine generated plasma particles, which will be described later.

A disk-shaped shutter 15 is provided with a slight gap from the front edge of the partition wall 9 and is opened and closed by a drive mechanism 14 to open and close the partition opening.

In the gap 10 between the front edge of the partition wall 9 and the inner wall surface of the reaction chamber 1, there is a rotatable disk-shaped transfer plate 19 holding the semiconductor wafer 8 with a clip 18 in the wafer fixing hole 17, and a partition wall with one transfer plate. A disk-shaped pressure plate 20 is provided parallel to the inner wall of the reaction chamber 1 and presses one transfer plate by a close contact mechanism (not shown) located on the 9 side. These transfer plates 1, 1, pressure plate 20, and the inner wall surface of reaction tank 1 are each attached so that they can be separated from each other,
When moving the semiconductor wafer 8 to another processing chamber, for example, the second sputtering processing chamber 6, the pressure plate 20 is moved back toward the partition wall 9 so that one transfer plate can rotate.

Note that the illustrated state shows that the sputtering process is in progress, and shows a state in which the transfer plate 19 is pressed by the pressure plate 20 and its movement is restricted.

A heater block 21 for preheating the wafer is arranged on the back surface of the semiconductor wafer 8, and a sputtering waste introduction pipe 22 is provided passing through the heater block 21. The sputtering gas generated by the reaction gas generator 35 flows through the gas introduction pipe 22 and flows into the reaction chamber 1 through an outlet 22 a provided on the outer periphery of the back surface of the semiconductor wafer 8 .

Externally, the reaction tank 1 includes a target detection mechanism as well as an integrated power measuring device for measuring the integrated value of the power supply amount and power supply time from the power source 30 to the target 8 and outputting the integrated power measurement value, and a target detector. 1. Input the integrated power measurement value input device W32 for presetting and inputting the integrated power setting value set as the life standard, and input the integrated power measurement value and the integrated power setting value, and compare the two to determine the target lifespan. A target life detection device 33 for determining the target life is provided.

The sputtering operation of such a sputtering apparatus is performed by first transporting the semiconductor wafer 8 into the sputtering chamber 5, and then vacuuming the inside of the reaction chamber 1 to a high vacuum, e.g., 10-7
Torr, and a high-temperature sputtering gas, such as argon gas, is introduced from the gas introduction pipe 22. At this time, the heat of the sputtering gas is transferred to the semiconductor wafer 8 via the heater block 21 and heats it. Next, at an appropriate timing according to a predetermined program, the target 11
The sputtering gas introduced into the reaction tank 1 is turned into plasma near the target 11 by applying electric power to the reactor 1 .

The sputtering gas turned into plasma is temporarily confined in a donut shape near the sputtering surface of the target 11 as shown by B in the figure due to the magnetic field A generated near the target 11, and the plasma particles excited at this time collide with the target 11. Knock out flying particles a. and shutter 15
When it rotates and opens, the ejected flying particles a fly into the sputtering chamber, and some of these flying particles adhere and deposit on the semiconductor wafer 8, thereby achieving the formation of a flying thin film.

However, as the above-described sputtering operation progresses, the target gradually wears out, causing problems such as a decrease in film-forming efficiency and an uneven distribution of the M thickness of the formed thin film.

For this reason, it is necessary to periodically replace the target in the sputtering apparatus, and a target lifespan detection device is provided to detect the lifespan of the target and notify when to replace it.

The operation of the target life detection device of this example will be explained below with reference to the flowchart of FIG.

First, the integrated power set value input device 32 inputs in advance into the target life detecting device 33 an integrated power setting value that serves as a reference for the target lifespan and stores it (101). Next, the integrated power of the target in use is measured, and the measurement result is supplied to the target life detection device 33. In this target life detection bag RL 33, compare this integrated power setting value with the integrated power measurement value (102) input from the integrated power measuring device (103), and if the integrated power measurement value is smaller than the integrated power setting value, the It determines that the life of the target is not yet reached and continues the current sputtering work.104) If the cumulative power measurement value is larger than the cumulative power setting value, it determines that the target life has ended and outputs a target life alarm. (107). At this time, if the sputtering operation is not automatically stopped in order to prevent the occurrence of defective products (105), a power supply stop signal may be output (108) to stop the power supply. Of course, the target life detection device described above may also be used as a monitoring mechanism for the target consumption state.

Incidentally, since the integrated power setting value, which serves as a reference for the target life, changes depending on the shape, material, etc. of the target, it is necessary to determine the correlation between the integrated power value and the target life in advance. An experiment was conducted as an example for determining the correlation between the target life and the integrated power value, and will be explained with reference to FIGS. 4 and 5. Note that since FIG. 4 and FIG. 5 correspond to each other, the same explanatory parts are given the same reference numerals.

The target used in the experiment had a sputtering surface in the shape of an inverted conical ring, had an inner diameter of 95 mm, an outer diameter of 18011 mm, and a thickness of about 35 mm, and was made of high-purity aluminum. Argon gas was used as the sputtering gas. Furthermore, the product of plasma discharge time and power supply amount is used as the integrated power value. Sputtering work was performed under the above conditions, and the relationship between the integrated power value and the number of wafers processed was determined.

As shown in the figure, the shape of the sputtered surface changes due to target consumption, although it was flat before use (Figure 4 (a)).
When the integrated power value is about 130 kW11 and the number of wafers processed -11 is 1000, the center of the sputtering surface is eroded upward by the wear of the target (FIG. 4(b)). When the integrated power value was 270 kwH and the number of wafers processed was 1800, the consumption progressed further and the sputtering surface became horizontally shaped (FIG. 4(C)), which was the limit for normal sputtering work. Therefore, the lifespan of the target used in this experiment was found to be 270 KwH, and when using this target, if the integrated power setting value is set to 270 KwH, it is possible to always know when to replace the target while it is in a constant state of consumption.

Incidentally, in this experiment, the sputtering processing conditions, such as the amount of power supplied, the sputtering time, and the time in which the sputtering operation is not performed when the shirt shirt is closed, that is, the time in the idling state, were kept constant, so the cumulative power value and the number of wafers processed were Although the relationship is proportional as shown in FIG. 5, in actual sputtering operations, these sputtering conditions may be changed during the sputtering operation, and in such cases, the proportional relationship does not hold. Therefore, the conventional means of detecting target life based on the number of wafers processed cannot accurately determine the target life, but in this example, the target life is determined based on the integrated power value without depending on the number of wafers processed. Therefore, accurate target life can be detected even in such cases.

[Effects of the Invention] As explained above, according to the sputtering apparatus of the present invention, it is possible to always accurately detect the target life regardless of changes in sputtering conditions, so it is possible to accurately know when to replace the target.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the arrangement of a sputtering chamber of a sputtering apparatus according to an embodiment of the present invention, FIG. 2 is a partial sectional view showing details of the sputtering chamber, and FIG. 3 is a target life detection diagram of an embodiment. FIG. 4 is a flow chart showing the operation of the apparatus, FIG. 4 is a chart showing changes over time in the consumption state of the target, and FIG. 5 is a chart showing the correlation between the integrated power amount and the number of wafers processed. 1...Reaction tank, 5...Sputter processing chamber, 8...Semiconductor wafer, 11...Target, 3o...Power supply, 31...
Integral power measuring device, 32... Integral power setting value input device, 33. Old target life detection device. Applicant Tokyo Elec 1 Heron Co., Ltd. Agent Patent Attorney Sasu Suyama - Figure 2 Figure 3

Claims (2)

[Claims] (1) In a sputtering device that sputters a target and forms a thin film on a substrate using flying particles, the life of the target is detected from the integrated power value of the amount of power supplied to the target and the time of power supply to the target. A sputtering device characterized by comprising means. (2) The sputtering apparatus according to claim 1, wherein the power supply time is the plasma discharge time.