Electrostatic chuck vacuum chamber test equipment

Abstract

The utility model discloses an electrostatic chuck vacuum chamber test device, which comprises a sealed chamber, an electrostatic chuck and a mounting seat for fixing the electrostatic chuck are arranged in the sealed chamber, an air passage is arranged in the electrostatic chuck, a helium inlet pipeline is connected onto the air passage, and a flowmeter and a feedback probe are further connected onto the helium inlet pipeline. A first switch and a second switch are arranged at the two ends of the flowmeter respectively, the electrostatic chuck is connected with electrostatic generation equipment, the sealing cavity is connected with a calibration air channel and a vacuumizing air channel, the calibration air channel and the vacuumizing air channel are both connected to the dry pump, and the calibration air channel and the vacuumizing air channel are provided with a fourth switch and a fifth switch respectively. The device has the beneficial effects that the accuracy of the flowmeter and the probe is ensured through calibration in advance, and meanwhile, the authenticity in a subsequent vacuum state is ensured, so that the subsequent measurement result is more real, and the quality of the ex-factory electrostatic chuck is ensured to be reliable; and through combined use of the dry pump and the molecular pump, the specified vacuum effect can be achieved more quickly.

Description

Technical Field

[0001] The utility model relates to the technical field of electrostatic chucks, in particular to an electrostatic chuck vacuum chamber testing device. Background Art

[0002] Electrostatic chuck, also known as electrostatic suction cup, is a general term for ultra-clean thin film carriers and grasping and handling equipment suitable for atmospheric or vacuum environments. Compared with traditional vacuum suction cups, electrostatic suction cups have better adsorption effects in vacuum environments.

[0003] During wafer processing or silicon wafer processing, it is necessary to deposit an ultra-thin film on the surface of the wafer or silicon wafer. Such ultra-thin films are processed by PVD or CVD technology. Both PVD and CVD technology need to be carried out in a vacuum environment. At the same time, the raw materials need to be effectively fixed during the deposition process, which makes the applicability of traditional suction cups used for fixing worse. The use scenarios of electrostatic suction cups are greatly improved, but in the wafer processing process, helium is needed to control the processing temperature of the wafer on the back side, which makes the electrostatic suction cup have a certain deviation in the adsorption force of the wafer under a vacuum state. Therefore, after the manufacturer produces the electrostatic suction cup, it is necessary to measure the influence of the introduction of helium on the adsorption force of the suction cup under a vacuum state. However, the existing device has a large error during the test, resulting in the suction cup being sent to the customer after leaving the factory and failing to work normally due to poor adsorption force. Therefore, there is an urgent need for a device that can accurately measure the adsorption effect of the suction cup under a vacuum state. Utility Model Content

[0004] (I) Technical solution

[0005] In order to solve the above technical problems, the utility model provides an electrostatic chuck vacuum chamber testing device.

[0006] The specific technical solutions are:

[0007] An electrostatic chuck vacuum chamber testing device comprises a sealed chamber, wherein an electrostatic chuck and a mounting base for fixing the electrostatic chuck are arranged in the sealed chamber, an air duct is arranged in the electrostatic chuck, the air duct is connected to a helium inlet pipeline, a flow meter and a feedback probe are also connected to the helium pipeline, a first switch and a second switch are respectively arranged at both ends of the flow meter, an electrostatic generating device is connected to the electrostatic chuck, a calibration air duct and a vacuum air duct are connected to the sealed chamber, the calibration air duct and the vacuum air duct are both connected to a dry pump, and a fourth switch and a fifth switch are respectively arranged on the calibration air duct and the vacuum air duct, the calibration air duct and the helium inlet pipeline are mutually connected through a pipeline, and a third switch is arranged on the connecting pipeline.

[0008] Furthermore, the sealed chamber is provided with two sets of pressure gauges, with measurement accuracies of 0.1 torr and 10 torr respectively.

[0009] Furthermore, a molecular pump is provided on the vacuum air extraction passage.

[0010] Furthermore, a lifting mechanism is provided at the bottom of the mounting seat, and the lifting mechanism is a telescopic rod, and there are at least two sets of the lifting mechanisms.

[0011] Furthermore, a lifting mechanism is provided on the upper portion of the mounting seat along the outer edge of the electrostatic chuck, and the lifting mechanism is a telescopic rod, and the telescopic rods are divided into multiple groups.

[0012] Furthermore, the top of the sealed chamber is made of transparent material.

[0013] (II) Beneficial effects

[0014] Compared with the prior art, the technical solution proposed by the utility model has the following advantages:

[0015] (1) Through prior calibration, the passage is also evacuated to ensure the authenticity of the subsequent vacuum state, making the subsequent measurement results more realistic and ensuring the quality of the electrostatic chuck leaving the factory;

[0016] (2) By using a dry pump and a molecular pump in combination, the specified vacuum effect can be achieved more quickly;

[0017] (3) The adsorption effect of the electrostatic chuck is measured and fed back by helium detection. The data is closer to the on-site process of the enterprise and the subsequent use status is simulated to ensure that the test scenario of the electrostatic chuck is more realistic. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 This is a structural diagram of Embodiment 1; DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the utility model embodiments to clearly and completely describe the technical solutions in the utility model embodiments. The described embodiments are only part of the utility model embodiments, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0021] During wafer processing or silicon wafer processing, it is necessary to deposit an ultra-thin film on the surface of the wafer or silicon wafer. Such ultra-thin films are processed by PVD or CVD technology. Both PVD and CVD technology need to be carried out in a vacuum environment. At the same time, the raw materials need to be effectively fixed during the deposition process, which makes the applicability of traditional suction cups used for fixing worse. The use scenarios of electrostatic suction cups are greatly improved, but in the wafer processing process, helium is needed to control the processing temperature of the wafer on the back side, which makes the electrostatic suction cup have a certain deviation in the adsorption force of the wafer under a vacuum state. Therefore, after the manufacturer produces the electrostatic suction cup, it is necessary to measure the influence of the introduction of helium on the adsorption force of the suction cup under a vacuum state. However, the existing device has a large error during the test, resulting in the suction cup being sent to the customer after leaving the factory and failing to work normally due to poor adsorption force. Therefore, there is an urgent need for a device that can accurately measure the adsorption effect of the suction cup under a vacuum state.

[0022] In order to solve the problems existing in the related prior art, the utility model proposes an electrostatic chuck vacuum chamber testing device. The principle and structure of the utility model are described in detail below in conjunction with the accompanying drawings and embodiments.

[0023] Embodiment 1: First, the principle of helium leak detection is briefly explained. For leak detection by vacuum method, the test piece is first evacuated and the interior is connected to the leak detector. Helium is sprayed from top to bottom and from near to far (relative to the position of the leak detector) at the position where the test piece may have a leak using a spray gun. If there is a leak, the helium will be immediately sucked into the vacuum system and the helium mass spectrometer leak detector will respond. Specifically applied to the field of suction cup testing, the electrostatic chuck can be installed in a sealed chamber, and then the interior is evacuated to a vacuum state, and then a wafer is placed on the electrostatic chuck, and the static electricity generating device is turned on. The wafer is adsorbed on the electrostatic chuck, and then helium is introduced through the airway on the back of the wafer, and a helium mass spectrometer leak detector is connected to the vacuum chamber. When the adsorption force of the electrostatic chuck is good, helium will not leak into the vacuum chamber from the gap between the electrostatic chuck and the wafer. When the adsorption force is insufficient, helium will form a gap between the electrostatic chuck and the back of the wafer, and helium will leak into the vacuum chamber from the gap. The helium mass spectrometer leak detector will detect the helium signal, and the smaller the adsorption force, the more helium leaks. Based on this, it is possible to confirm whether the adsorption force meets the standard according to the helium leakage rate. In this embodiment, the detection requirement is set to a vacuum degree of the vacuum chamber of 1*10 -9 Pa·m 3 / s, under 8Torr helium pressure and the helium leakage rate is required to be less than 1.5sscm to be qualified. The specific setting can be based on different requirements. The structure is described in detail below.

[0024] An electrostatic chuck vacuum chamber testing device includes a sealed chamber 1, one side of which can be opened to facilitate replacement of different electrostatic chucks that need to be tested. Specifically, a sealed chamber with an upper opening can be selected, and of course it is not limited to a sealed chamber structure with an upper opening. The upper opening chamber is taken as an example here. At the same time, in order to facilitate observation of the internal situation, the upper opening adopts a thick transparent acrylic plate, which provides a cover plate required for sealing on the one hand, and can also more conveniently observe the internal situation. An electrostatic chuck 2 and a mounting seat 3 for fixing the electrostatic chuck are provided in the sealed chamber 1. The mounting seat is fixed to the bottom of the sealed chamber and is used to fix the electrostatic chuck 2 to be measured, and the mounting seat is also connected to an electrostatic generating device 9 and the electrostatic chuck. The electrostatic generating device enables the electrostatic chuck to generate an electrostatic adsorption force on the wafer. In this embodiment, the rated electrostatic adsorption voltage is ±2500V DC, an airway is provided in the electrostatic chuck 2, and the airway is connected to a helium inlet pipeline 4. When the wafer is placed on the electrostatic chuck, helium is introduced through the helium inlet pipeline, and the helium is transported to the back of the wafer. When the adsorption force provided by the electrostatic chuck is insufficient, the helium will blow up the wafer, and a gap will appear between the wafer and the electrostatic chuck, and the helium will leak into the sealed chamber from the gap. At the same time, a flow meter 5 and a feedback probe 6 are also connected to the helium inlet pipeline 4. The flow meter 5 is used to measure the flow rate and helium pressure generated when the helium is introduced, and the feedback probe 6 is used to measure the flow rate and helium pressure generated when the helium is introduced. In order to detect the leakage rate of helium when it leaks into the sealed chamber, a first switch 7 and a second switch 8 are respectively provided at both ends of the flowmeter 5, an electrostatic generating device 9 is connected to the electrostatic chuck 2, a calibration air duct and a vacuum air duct are connected to the sealed chamber 1, the calibration air duct and the vacuum air duct are both connected to a dry pump 10, the dry pump is used to evacuate the sealed chamber, and a fourth switch 11 and a fifth switch 12 are respectively provided on the calibration air duct and the vacuum air duct, the calibration air duct and the helium inlet pipeline 4 are interconnected through a pipeline, and a third switch 13 is provided on the connecting pipeline.

[0025] During the specific work, the electrostatic chuck is first fixed on the mounting base 3, and the wafer is mounted on the electrostatic chuck. Then, the electrostatic adsorption device is turned on and the voltage is adjusted to ±2500V DC. The adsorption and contact adsorption of the electrostatic chuck are tested under normal pressure to ensure that all connections are normal.

[0026] Then, the top sealing cover is placed on the sealed chamber 1 to seal the inside of the chamber. At the same time, the dry pump 10 is turned on to evacuate the inside through the vacuum duct so that the internal pressure is 1*10 -9 Pa·m 3 / s, the efficiency of ordinary dry pumps is low. At this time, a molecular pump 14 can be set on the vacuum air channel. Through the synchronous operation of the molecular pump 14 and the dry pump, the specified vacuum degree can be reached more quickly. At the same time, in order to characterize the internal vacuum degree, a pressure gauge is set on the side of the sealed chamber, and the number of pressure gauges is 2, and the measurement accuracy is 0.1torr and 10torr. In this way, it can be more accurately determined whether the internal vacuum degree meets the specified requirements.

[0027] When the vacuum is evacuated to the specified requirement, the first switch 7 and the third switch 13 are opened, and the second switch 8 and the fourth switch 11 are closed, and the conditions of the flow meter 5 when He with pressures of 3, 5, and 8 Torr enter are measured respectively, for a calibration purpose.

[0028] When the calibration is completed, the wafer is placed on the electrostatic chuck 2, the electrostatic generating device 9 is turned on, the wafer is adsorbed on the electrostatic chuck, and then the first switch 7, the second switch 8 and the fourth switch are turned on, and helium enters the back of the wafer. When helium escapes from the gap between the wafer and the electrostatic chuck into the sealed chamber 1, it returns to the feedback probe 6 through the channels of the fourth switch 11 and the third switch 13, and the leakage rate is accepted. The helium leakage rates received under pressures of 3, 5, and 8 Torr are measured respectively. When the leakage rate is less than 1.5sscm at a pressure of 8Torr, it is qualified, and if it exceeds 1.5sscm, it is unqualified.

[0029] After the measurement is completed, the pressure is released to restore the sealed chamber to normal pressure. The original electrostatic chuck is removed and replaced with a new one to repeat the above operation. Generally, in order to facilitate the placement and removal of wafers, a lifting mechanism is set at the bottom of the mounting seat or the bottom of the electrostatic chuck, specifically a telescopic rod. When a wafer is incoming, the electrostatic chuck is lifted or the telescopic rod is extended to catch the wafer, and then the wafer is retracted and falls on the electrostatic chuck. Specifically, a lifting mechanism 15 can be set at the bottom of the mounting seat 3, and the lifting mechanism is a telescopic rod, and there are at least 2 groups, or a lifting mechanism 15 is set at the top of the mounting seat along the outer edge of the electrostatic chuck, and the lifting mechanism 15 is a telescopic rod, and there are multiple groups of telescopic rods. Both of the above methods can achieve the above effect.

[0030] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may be subject to various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An electrostatic chuck vacuum chamber testing device, characterized in that: The invention comprises a sealed chamber (1), wherein an electrostatic chuck (2) and a mounting base (3) for fixing the electrostatic chuck are arranged in the sealed chamber (1), an air duct is arranged in the electrostatic chuck, the air duct is connected to a helium inlet pipeline (4), the helium inlet pipeline (4) is also connected to a flow meter (5) and a feedback probe (6), a first switch (7) and a second switch (8) are arranged at two ends of the flow meter (5), an electrostatic generating device (9) is connected to the electrostatic chuck (2), a calibration air duct and a vacuum air duct are connected to the sealed chamber (1), the calibration air duct and the vacuum air duct are both connected to a dry pump (10), and a fourth switch (11) and a fifth switch (12) are arranged on the calibration air duct and the vacuum air duct respectively, the calibration air duct and the helium inlet pipeline (4) are connected to each other through a pipeline, and a third switch (13) is arranged on the connecting pipeline.

2. The electrostatic chuck vacuum chamber testing device according to claim 1, characterized in that: The sealed chamber (1) is provided with two sets of pressure gauges (16), with measurement accuracies of 0.1 torr and 10 torr respectively.

3. The electrostatic chuck vacuum chamber testing device according to claim 2, characterized in that: The vacuum air extraction passage is also provided with a molecular pump (14).

4. The electrostatic chuck vacuum chamber testing device according to claim 1, characterized in that: A lifting mechanism (15) is provided at the bottom of the mounting seat (3), and the lifting mechanism is a telescopic rod, and there are at least two sets of the lifting mechanisms.

5. The electrostatic chuck vacuum chamber testing device according to claim 1, characterized in that: A lifting mechanism (15) is provided on the upper part of the mounting seat along the outer edge of the electrostatic suction cup. The lifting mechanism (15) is a telescopic rod, and the telescopic rods are divided into multiple groups.

6. The electrostatic chuck vacuum chamber testing device according to claim 1, characterized in that: The top of the sealed chamber (1) is made of transparent material.

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