An apparatus, method, and etching apparatus for reducing wafer drop rate in etching processes.

Abstract

This invention relates to the field of deep silicon etching technology for semiconductors, and discloses a method, apparatus, and etching apparatus for reducing wafer drop rate during etching processes. The apparatus for reducing wafer drop rate includes a venting controller and a ceramic shielding disk. One end of the venting controller is connected to an air inlet pipe, and the other end is connected to the venting pipe of the etching equipment. The ceramic shielding disk is disposed on the lower electrode base of the etching equipment. After etching, the venting controller introduces gas into the etching equipment, causing the wafer to float and fall, thereby eliminating the residual electrostatic adhesion effect on the wafer after etching. The ceramic shielding disk limits the movement range of the wafer during the floating process. The apparatus for reducing wafer drop rate provided by this invention, through the combined use of the ceramic shielding disk and the venting controller, eliminates the residual electrostatic adhesion effect on the wafer after etching, solving the problem of high wafer drop rate in existing etching processes.

Description

Technical Field

[0001] This invention relates to the field of semiconductor deep silicon etching technology, and more particularly to an apparatus, method and etching apparatus for reducing wafer drop rate in etching processes. Background Technology

[0002] In inductively coupled deep silicon etching (ICD) systems, wafers are transferred using a robotic wafer carrier. Electrostatic chucks (ESCs) are used to hold the wafers in place within the process cavity. The basic principle of an ESC is the attraction between positive and negative charges; the Coulomb force between these opposite charges stabilizes the wafer on the electrodes. The most common type is the bipolar ESC, where the positive and negative terminals of the power supply are connected to the two electrodes. The wafer is internally polarized, generating opposite charges to the ESC electrodes. The Coulomb force between these opposite charges holds the wafer on the ESC. Besides wafer fixation, another function of the ESC is temperature control. A high-voltage DC voltage is applied to the ESC to hold the wafer in place. Helium gas is injected through a ring of small holes on the ESC's surface. Heat generated during the process is transferred through the circulating helium gas, reducing the wafer temperature and thus stabilizing it. The lifting pins also move up and down via these helium injection holes.

[0003] In the deep silicon etching process, the wafer is first placed on a robotic carrier. Once the loadlock cavity of the inductively coupled deep silicon etching system matches the vacuum level of the process cavity, the isolation valve is opened. The robotic arm then transfers the wafer from the carrier to directly above the ejector pin of the ESC (Electronic Steering Center). The ejector pin rises, lifting the wafer from the carrier. At this point, the wafer is higher than the carrier, the robotic arm retracts into the loadlock cavity, the isolation valve closes, and the ejector pin descends below the upper surface of the ESC. The wafer is then placed on the ESC, which applies a DC voltage to hold it in place. After the process gas is introduced and stabilized, etching begins on the wafer. The wafer thickness is approximately 250–400 micrometers. During deep silicon etching, when the via size is large, a film needs to be applied to the back of the wafer before placing it on the ESC. This ensures that the back of the wafer is kept under a certain pressure range during helium cooling, meeting the wafer's cooling requirements.

[0004] However, when the DC voltage applied to the ESC is turned off after the process of back-coated wafers, incomplete electrostatic discharge can occur, resulting in residual electrostatic adhesion. This means that when the ejector pins on the upper surface of the ESC lift the wafer, the outer circumference rises while the center remains attached to the ESC. After the outer circumference has risen a certain height, the center of the wafer suddenly detaches, causing it to jump rapidly. In a vacuum environment, the wafer may deviate significantly from the ejector pins or even fall into the process chamber. This prevents the robotic arm from removing the wafer from the process chamber and transferring it to the Loadlock chamber. Instead, the vacuum chamber must be manually inflated to atmospheric pressure, the upper electrode opened, the wafer manually removed, the lower electrode and reactant particles cleaned, the electrodes reassembled, and the vacuum re-evacuated. This process takes over an hour, resulting in a wafer drop rate exceeding 50% during back-coated wafer processing, severely impacting daily production capacity. Summary of the Invention

[0005] This invention provides an apparatus, method, and etching apparatus for reducing wafer drop rate in etching processes, solving the problem of high wafer drop rate in existing etching processes.

[0006] In a first aspect, embodiments of the present invention provide an apparatus for reducing wafer drop rate during etching processes, characterized in that it includes a ventilation controller and a ceramic shielding disk; one end of the ventilation controller is used to connect to an air inlet pipe, and the other end is used to connect to the ventilation pipe of the etching equipment; the ceramic shielding disk is disposed on the lower electrode base of the etching equipment; the ventilation controller is used to introduce gas into the etching equipment after etching is completed, causing the wafer to float and fall, thereby eliminating the residual electrostatic adhesion effect on the wafer after etching; the ceramic shielding disk is used to limit the movement range of the wafer during the wafer floating process.

[0007] Based on the first aspect, in some embodiments, the ventilation controller includes a first relay, a second relay, a third relay, a push-button switch, an electromagnetic shut-off valve, and a vacuum gauge; the first relay, the second relay, the third relay, and the push-button switch are used to form a control circuit for the ventilation controller; the vacuum gauge is used to detect the real-time vacuum value at the ventilation pipeline of the etching equipment and upload the real-time vacuum value to the control circuit of the ventilation controller; the electromagnetic shut-off valve is installed on the air inlet pipeline, and the control circuit of the ventilation controller controls the electromagnetic shut-off valve according to the real-time vacuum value to realize the control of the opening and closing of the air inlet pipeline of the ventilation controller.

[0008] Based on the first aspect, in some embodiments, the ventilation controller further includes a mass flow controller; an electromagnetic shut-off valve is connected to the ventilation controller's inlet pipe, the mass flow controller is connected to the electromagnetic shut-off valve, a vacuum gauge is located at the mass flow controller's outlet, and the mass flow controller is connected to the ventilation pipeline of the etching equipment; the mass flow controller is used to adjust the gas flow rate when the ventilation controller's inlet pipe is open.

[0009] Based on the first aspect, in some embodiments, the ventilation controller further includes a needle valve disposed on the ventilation controller's air inlet pipe for controlling the amount of air intake in the ventilation controller's air inlet pipe.

[0010] Based on the first aspect, in some embodiments, the vacuum gauge is connected in series with the coil of the first relay.

[0011] Based on the first aspect, in some embodiments, the electromagnetic shut-off valve is connected in series with the normally closed contact of the first relay, the normally open contact of the second relay, and the delayed disconnecting normally closed contact of the third relay.

[0012] Based on the first aspect, in some embodiments, the normally open contact of the second relay is connected in parallel with the push-button switch and then connected in series with the coil of the second relay, the time-delayed normally closed contact of the third relay, and the normally closed contact of the first relay; the coil of the third relay is connected in series with the normally open contact of the second relay.

[0013] Based on the first aspect, in some embodiments, a limiting pin is provided on the ceramic shielding disk. The limiting pin is located at a certain distance from the inner circumferential edge on the upper surface of the ceramic shielding disk, and the limiting pin is used to limit the movement range of the wafer.

[0014] Secondly, embodiments of the present invention provide a method for reducing wafer drop rate in etching processes, applicable to any of the apparatuses described in the first aspect above for reducing wafer drop rate in etching processes, comprising: detecting the real-time vacuum value in the ventilation pipeline of the etching equipment through a ventilation controller; performing a vacuum extraction operation on the etching equipment when the real-time vacuum value is greater than a first preset value; and introducing gas into the ventilation pipeline of the etching equipment when the vacuum value is less than the first preset value, causing the wafer to float; restricting the position of the floated wafer from deviating from a preset area through a ceramic shielding disk; and stopping ventilation after the ventilation controller detects that the real-time vacuum value is greater than the first preset value, causing the wafer to fall.

[0015] Thirdly, embodiments of the present invention provide an etching apparatus, characterized in that it includes an etching device and a device for reducing the wafer drop rate in the etching process as described in any one of the first aspects; the etching device is used to etch wafers, and the device for reducing the wafer drop rate in the etching process is used to eliminate the residual electrostatic adhesion effect on the wafer after the etching process is completed, so that the wafer can be stably removed from the etching device.

[0016] In this embodiment, the device for reducing wafer detachment during etching utilizes a ceramic shielding disk and a ventilation controller. After the etching process is complete, a uniform airflow is formed on the back of the wafer by jetting gas. The pressure difference generates buoyancy, causing the wafer to detach from the residual electrostatic force and float upwards. This invention eliminates the residual electrostatic force adhesion effect on the wafer after the etching process, solving the problem of high wafer detachment rates in existing etching processes. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the electrostatic chuck device provided in an embodiment of the present invention;

[0019] Figure 2 This is a structural diagram of the inductively coupled deep silicon etching apparatus provided in an embodiment of the present invention;

[0020] Figure 3 This is a schematic diagram of the wafer circumferentially lifted state provided in an embodiment of the present invention;

[0021] Figure 4 This is a schematic diagram illustrating the wafer center detaching from the ESC and exhibiting a skipping state, provided in an embodiment of the present invention.

[0022] Figure 5 This is a schematic diagram of the offset state of the wafer after it jumps back onto the ejector pin, provided in an embodiment of the present invention.

[0023] Figure 6 This is a schematic diagram of the state of a wafer sliding back onto the ejector pin after being skipped, as provided in an embodiment of the present invention.

[0024] Figure 7 This is a schematic diagram of an apparatus for reducing wafer loss during etching processes, provided in an embodiment of the present invention.

[0025] Figure 8 This is a schematic diagram of the control circuit of the ventilation controller provided in an embodiment of the present invention;

[0026] Figure 9 This is a schematic diagram of the planar structure of the ventilation controller provided in an embodiment of the present invention;

[0027] Figure 10 This is a schematic diagram of the ceramic shielding disc provided in an embodiment of the present invention;

[0028] Figure 11A flowchart of a method for reducing wafer drop rate in etching processes provided in this embodiment of the invention;

[0029] Figure 12 This is a process flow diagram of the method for reducing wafer loss rate in etching processes provided in the embodiments of the present invention;

[0030] Figure 13 This is a schematic diagram of the etching device structure provided in an embodiment of the present invention.

[0031] In the picture:

[0032] 101 Loadlock cavity;

[0033] 102 Isolation valve;

[0034] 102 Source Radio Frequency;

[0035] 104 Reaction Chamber;

[0036] 105 Inductively Coupled Coil;

[0037] 106 Ceramic cavity;

[0038] 107 wafers;

[0039] 108 ESC;

[0040] 109. Threshold pin;

[0041] 110 biased RF;

[0042] 111 cylinder;

[0043] 201 Ceramic shielding plate;

[0044] 202 Ventilation controller. Detailed Implementation

[0045] To enable those skilled in the art to better understand the present invention, the technical solutions of the embodiments of the present invention will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0046] The term "comprising" and any other variations thereof in the specification, claims, and accompanying drawings of this invention mean "including but not limited to," and are intended to cover a non-exclusive inclusion, not limited to the examples listed herein. Furthermore, the terms "first" and "second," etc., are used to distinguish different objects, not to describe a particular order.

[0047] The implementation of the present invention will be described in detail below with reference to the accompanying drawings:

[0048] Inductively coupled deep silicon etching (ICD) is a semiconductor etching process based on the Bosch process principle. During passivation, a polymer gas is introduced into the reaction chamber. After plasma ionization, the resulting polymer is deposited on the surface of the silicon wafer to be etched. This process is highly isotropic, thus uniformly coating the surface of the silicon wafer and the deep trenches with a polymer protective film. In the subsequent etching process, the gas in the reaction chamber is converted into an etching gas. The ionized etching gas is reactive, and the plasma generated at the top is influenced by the lower electrode, causing ions to move in a directional manner. A magnetic field is applied around the equipment to confine the movement of charged ions and free radicals, thus ensuring good directionality and uniformity, achieving anisotropic etching. High aspect ratio deep silicon etching is achieved through the alternation of deposition protection and etching.

[0049] Deep silicon etching equipment typically uses electrostatic chucks (ESCs) to hold the wafers to be etched. The basic principle of an ESC is the attraction between positive and negative charges; the wafer is held to the electrodes by the Coulomb force between the different charges. The most common type is the bipolar electrostatic chuck, such as... Figure 1 As shown, the positive and negative terminals of the power supply are connected to the two electrodes of ESC. The wafer is polarized inside and generates charges of opposite polarity with the two electrodes of ESC. The Coulomb force between the opposite charges fixes the wafer to ESC.

[0050] Besides fixing the wafer, the ESC (Electronic Stress Controller) also functions as a temperature control mechanism. A high-voltage DC current is applied to the ESC to adhere the wafer to its upper surface. Helium gas is injected through a ring of small holes on the upper surface. The heat generated by the wafer during the process is transferred through the circulating helium gas, reducing the wafer's temperature and thus stabilizing it. Additionally, the small holes on the ESC's upper surface also serve as extension holes for ejector pins. When it is necessary to raise or lower the wafer, a gas pump controls the ejector pins to lift or lower the wafer.

[0051] Figure 2A typical deep silicon etching apparatus is shown. The specific process of etching using this apparatus is as follows: The wafer is first placed on the robotic carrier. After the vacuum levels of the Loadlock chamber 101 and the reaction chamber 104 are matched, the isolation valve 102 is opened. The robotic arm transfers the wafer 107 from the carrier to directly above the ejector pin 109. The ejector pin 109 then rises to lift the wafer 107 from the carrier. At this point, the wafer 107 is higher than the carrier. The robotic arm retracts to the Loadlock chamber 101, the isolation valve 102 is closed, and the ejector pin 109 descends below the upper surface of the ESC 108, placing the wafer 107 on the ESC 108. The ESC 108 is subjected to a DC voltage to adsorb the wafer 107. After the process gas is introduced and stabilized, the radio frequency ignition is turned on and helium is introduced. Plasma, under the action of the inductively coupled coil 105, bombards the wafer 107 vertically downwards to etch it. The thickness of the wafer 107 is approximately 250–400 micrometers. During the etching of vias, when the via size of wafer 107 is large, a film needs to be attached to the back of the wafer before it is placed on the ESC. This ensures that the gas is introduced into the back of wafer 107 for cooling during the process and that the pressure is maintained within a certain range to meet the cooling requirements of the wafer.

[0052] However, when the DC voltage applied to the ESC is turned off after the process is completed, the residual electrostatic force on the wafer 107 with the back-mounted film is prone to sticking due to incomplete release of electrostatic force. This occurs when the pins on the upper surface of the ESC lift the wafer, the outer circumference of the wafer rises, while the center of the wafer remains attached to the ESC. Figure 3 As shown. When the ejector pin at the outer circumference rises to a certain height, the center of the wafer suddenly detaches, causing the wafer to jump rapidly, as... Figure 4 As shown. In a vacuum environment, wafers may deviate significantly from the ejector pins or even detach from them into the process chamber. The degree of wafer bounce varies depending on the electrostatic adsorption. Shorter plasma bombardment times result in lower residual electrostatic forces, leading to smaller wafer bounces and a greater likelihood of deviation. Figure 5 Plasma bombardment of wafers for extended periods results in significant residual electrostatic forces, causing the wafers to bounce considerably and potentially slip. Figure 6 .

[0053] When wafers shift or even slip, the robotic arm is unable to remove them from the process chamber into the loadlock chamber. Instead, the vacuum chamber must be manually inflated to atmospheric pressure, the upper electrode of the vacuum chamber opened, the wafer manually removed, the lower electrode and reactant particles in the chamber cleaned, the upper electrode reassembled, and the vacuum pumped back on. This process takes more than an hour. During the processing of wafers with back-side coating, the wafer drop rate is greater than 50%, which seriously affects daily production capacity.

[0054] To address the high wafer drop rate in existing etching processes, this invention proposes a device for reducing the wafer drop rate during etching, such as... Figure 7 As shown, the etching apparatus includes a ceramic shielding disk 201 and a venting controller 202. One end of the venting controller 202 is connected to the venting controller inlet pipe, and the other end is connected to the venting pipe of the etching equipment. The venting pipe of the etching equipment is connected to the reaction chamber of the etching equipment. The ceramic shielding disk 201 is disposed on the lower electrode base of the etching equipment. The venting controller 202 is used to introduce gas into the etching equipment after etching, causing the wafer 107 to float and fall, thereby eliminating the residual electrostatic adhesion effect on the wafer 107 after etching. The ceramic shielding disk 201 is used to limit the range of movement of the wafer 107 during the wafer floating process.

[0055] In some embodiments, such as Figure 8 As shown, the ventilation controller 202 includes a first relay K1, a second relay K2, a third relay K3, a push-button switch Z1, a solenoid shut-off valve, and a vacuum gauge.

[0056] The first relay K1, the second relay K2, the third relay K3, and the push-button switch Z1 are used to form the control circuit of the ventilation controller. The electromagnetic shut-off valve is used to control the opening and closing of the ventilation controller's air inlet pipe. The vacuum gauge is used to detect the real-time vacuum value at the ventilation pipe of the etching equipment and upload the real-time vacuum value to the control circuit of the ventilation controller.

[0057] In some embodiments, the ventilation controller further includes a mass flow controller (MFC). An electromagnetic shut-off valve is connected to the ventilation controller's inlet pipe, the mass flow controller is connected to the electromagnetic shut-off valve, a vacuum gauge is located at the mass flow controller's outlet, and the mass flow controller is connected to the ventilation line of the etching equipment. The mass flow controller is used to regulate the gas flow rate when the ventilation controller's inlet pipe is open.

[0058] In some embodiments, the vacuum gauge is connected in series with the coil of the first relay K1. The electromagnetic shut-off valve is connected in series with the normally closed contact of the first relay K1, the normally open contact of the second relay K2, and the delayed-open normally closed contact of the third relay. The normally open contact of the second relay K2 is connected in parallel with a push-button switch, and then connected in series with the coil of the second relay K2, the delayed-open normally closed contact of the third relay K3, and the normally closed contact of the first relay K1. The coil of the third relay K3 is connected in series with the normally open contact of the second relay K2.

[0059] After the etching process is completed, before the ejector pin rises from the top plate, the jog button Z1 of the ventilation controller is activated. This energizes the coil of the second relay K2, closing its normally open contact. The closure of the normally open contact of the second relay K2 energizes the coil of the third relay K3, closing its delayed-open normally closed contact and activating the delayed-open function. When the vacuum gauge detects a real-time vacuum value lower than a first preset value, the coil of the first relay K1 is not energized, and its normally closed contact remains closed. At this time, the electromagnetic shut-off valve opens, and the required gas flow rate is controlled by the mass flow controller to enter the equipment pipeline. When the vacuum gauge detects a real-time vacuum value higher than the preset value, the vacuum gauge outputs voltage, energizing the coil of the first relay K1. This opens the normally closed contact of the first relay K1, de-energizing the electromagnetic shut-off valve coil, closing the electromagnetic shut-off valve, and preventing further gas flow into the etching equipment's ventilation pipeline. Simultaneously, the opening of the normally closed contact of the first relay de-energizes the coil of the second relay K2, causing its normally open contact to open. This opening of the normally open contact of the second relay K2 de-energizes the coil of the third relay K3, causing its delayed-opening normally closed contact to open, thus disabling the delayed-opening function. When both the delayed-opening function and the disconnection function under the real-time vacuum value control of the vacuum gauge are activated simultaneously, both can control the solenoid shut-off valve to close.

[0060] In some embodiments, the front panel of the ventilation controller 202 is as follows: Figure 5 As shown, the device includes a flow display screen for the mass flow controller, a vacuum gauge display screen, and a start button. The flow display screen has control buttons; control button Fn selects the gas flow display mode, control button + increases the flow rate, and control button - decreases the flow rate. The vacuum gauge display screen shows the real-time vacuum value at the ventilation line of the etching equipment. The start button controls the jog switch in the control circuit of the ventilation controller. The jog switch is a non-locking jog button, controlled by a relay for self-locking.

[0061] The rear panel of the ventilation controller 202 has a round hole for installing the air intake pipe through-plate connector and a square hole for the power connector. A needle valve is also installed on the air intake pipe of the ventilation controller, which is used to control the air intake volume. The needle valve can roughly control the air intake volume, while the mass flow controller can precisely control the air intake volume. The optimal air intake volume can be determined through multiple experimental tests.

[0062] In some embodiments, the ventilation controller uses a 24VDC switching power supply to power the solenoid shut-off valve, MFC, relay, and jog switch.

[0063] In some embodiments, such as Figure 9 As shown, Figure 9 The left side shows a cross-sectional view of the ceramic shielding disc. Figure 9The right side shows a top view of the ceramic shielding disk. The ceramic shielding disk 201 is equipped with a limit pin, which is located at a certain distance from the inner circumference edge on the upper surface of the ceramic shielding disk 201. The limit pin is used to limit the movement range of the wafer.

[0064] The ceramic shielding disk 201 is placed on the aluminum lower electrode of the etching equipment to protect the lower electrode from plasma damage. It has a circular hole with a straight edge in the center, the shape of which is the same as that of the ESC, but slightly larger, so it can be used in conjunction with the ESC. Multiple blind holes are evenly distributed at a distance from the edge of the circular hole inside the ceramic shielding disk; for example, there can be three blind holes, with two of them symmetrically distributed on both sides of the circular hole with the straight edge.

[0065] like Figure 10 As shown, from left to right, the figures are a cross-sectional view, a front view, and a left view of the limiting pin. The top of the limiting pin is machined into a hemispherical shape, and the lower part is a long straight cylinder. The limiting pin is located inside a blind hole, and its position limits the offset of the wafer during the floating process within a certain range. The limiting pin is made of the same alumina ceramic as the shielding disk. The height of the limiting pin is designed so that after being installed on the ceramic shielding disk, it protrudes a certain height from the upper surface of the shielding disk, but is lower than the height of the robotic arm's wafer carrier when picking up the wafer from the top of the ceramic shielding disk. The top of the limiting pin is designed to be arc-shaped to avoid tip discharge caused by the small ceramic edge in the vacuum cavity.

[0066] The present invention also provides a method for reducing the wafer drop rate in etching processes, applicable to the aforementioned apparatus for reducing wafer drop rate in etching processes, such as... Figure 11 As shown, the method may include steps 101 to 103.

[0067] Step 101: Detect the vacuum value in the ventilation pipeline of the etching equipment through the ventilation controller. When the vacuum value is greater than the first preset value, perform a vacuum extraction operation. When the vacuum value is less than the first preset value, introduce gas into the ventilation pipeline to make the wafer float.

[0068] In some embodiments, a first preset value is set to V, and a vacuum value is set to V1. When the vacuum value V1 is greater than the first preset value V, a vacuum extraction operation is performed. When the vacuum value V1 is less than the first preset value V, gas is introduced into the ventilation pipe to make the wafer float. The first preset value V can be determined experimentally.

[0069] Step 102: Use a ceramic shielding disk to prevent the floating wafer from deviating from the preset area.

[0070] When gas is introduced to detach the wafer from the upper surface of the ESC, the wafer shifts. The limiting pin on the ceramic shielding disk prevents the wafer from shifting out of the preset area. The preset area can be a circular area centered on the upper surface of the ESC, and the radius of this circular area is a certain distance larger than the radius of the wafer.

[0071] Step 103: After the ventilation controller detects that the vacuum value is greater than the first preset value, the ventilation is stopped, allowing the wafer to fall.

[0072] Example 1,

[0073] like Figure 12 As shown, the etching reaction process flow for applying the method and apparatus for reducing the wafer shedding rate in the etching process includes the following steps:

[0074] 1) The robotic arm transfers the wafer from the Loadlock cavity to the ESC directly above the reaction cavity. The ejector pin rises from the helium injection port, lifting the wafer until it is detached from the robotic arm. The robotic arm retracts into the Loadlock cavity, the ejector pin descends, and the wafer is placed on the ESC.

[0075] 2) Run the etching process program.

[0076] 3) After the etching process is completed, shut off the back cooling gas and evacuate the ventilation pipeline of the etching equipment to a vacuum.

[0077] 4) Start the device used to reduce the wafer drop rate during the etching process.

[0078] 5) The vacuum gauge detects the real-time vacuum value V1 in the ventilation pipeline of the etching equipment, and the vacuum gauge is preset to a vacuum value V.

[0079] 6) When V1 > V, proceed to step 3); when V1 < V, the electromagnetic shut-off valve in the device used to reduce the wafer drop rate in the etching process is opened, and nitrogen gas is introduced into the ventilation pipeline of the etching equipment.

[0080] 7) Nitrogen gas enters the ventilation pipe of the etching equipment and is then introduced to the back of the wafer. Under the action of the gas pressure difference, the wafer is lifted up and restricted to offset within the limit pin.

[0081] 8) When the vacuum gauge detects V1 > V, the electromagnetic shut-off valve closes, the wafer slowly falls back onto the ESC, and the ventilation line of the etching equipment is evacuated to a higher vacuum.

[0082] 9) The ejector pins rise to lift the wafer.

[0083] 10) The robotic arm enters the reaction chamber above the ESC from the Loadlock chamber, the ejector pin descends, and the wafer falls onto the robotic arm to be retrieved back to the Loadlock chamber.

[0084] By employing devices and methods to reduce wafer drop rates during the etching process, nitrogen gas is introduced into the ventilation pipe after the etching process is completed. The nitrogen gas enters the back side of the wafer through the injection port, forming a uniform airflow on the back side of the wafer that lifts the wafer upward. The upper part of the wafer is in a vacuum environment below 1 mtorr, while the back side is subjected to the low pressure of the nitrogen gas. The pressure difference generates a sufficiently large buoyancy that causes the wafer to detach from the residual electrostatic force and float upward.

[0085] The wafer is slightly lifted on the ESC and confined within the area defined by the limiting pins before being lowered. Then, the wafer is lifted again using a ejector pin, allowing the robotic arm to properly pick it up and place it into the Loadlock. This invention solves the wafer skipping problem caused by the residual electrostatic force of the ESC, reducing the wafer skipping rate from >50% to ≤3% in actual testing.

[0086] like Figure 13 As shown, this embodiment of the invention also provides an etching apparatus 4, including an etching device 40 and the aforementioned device 41 for reducing the wafer drop rate during the etching process. The etching device 40 is used to etch wafers, and the device 41 for reducing the wafer drop rate during the etching process is used to eliminate the residual electrostatic adhesion effect on the wafer after the etching process is completed, so that the wafer can be stably removed from the etching device.

[0087] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. An apparatus for reducing wafer loss rate in etching processes, characterized in that, Includes ventilation controller and ceramic shielding plate; One end of the ventilation controller is used to connect to the air inlet pipe, and the other end is used to connect to the ventilation pipe of the etching equipment. The ceramic shielding plate is disposed on the lower electrode base of the etching equipment. The ventilation controller is used to introduce gas into the etching equipment after etching is completed, so that the wafer floats and falls, thereby eliminating the residual electrostatic adhesion effect on the wafer after etching. The ventilation controller also includes a mass flow controller; the mass flow controller is used to adjust the gas flow rate when the ventilation controller's air inlet pipe is open. The ventilation controller also includes a needle valve, which is disposed on the air inlet pipe of the ventilation controller and is used to control the amount of air entering the air inlet pipe of the ventilation controller. The ventilation controller includes a first relay, a second relay, a third relay, a push-button switch, a solenoid shut-off valve, and a vacuum gauge; The first relay, the second relay, the third relay, and the push-button switch are used to form the control circuit of the ventilation controller; The vacuum gauge is connected in series with the coil of the first relay; The electromagnetic shut-off valve is connected in series with the normally closed contact of the first relay, the normally open contact of the second relay, and the delayed disconnect normally closed contact of the third relay. The normally open contact of the second relay is connected in parallel with the push-button switch, and then connected in series with the coil of the second relay, the time-delayed normally closed contact of the third relay, and the normally closed contact of the first relay. The coil of the third relay is connected in series with the normally open contact of the second relay; The ceramic shielding disk is used to limit the range of movement of the wafer during the wafer's floating process.

2. The apparatus for reducing wafer loss rate in etching processes as described in claim 1, characterized in that, The vacuum gauge is used to detect the real-time vacuum value at the ventilation pipe of the etching equipment and upload the real-time vacuum value to the control circuit of the ventilation controller; the electromagnetic shut-off valve is installed on the air inlet pipe, and the control circuit of the ventilation controller controls the electromagnetic shut-off valve according to the real-time vacuum value to control the opening and closing of the air inlet pipe of the ventilation controller.

3. The apparatus for reducing wafer loss rate in etching processes as described in claim 2, characterized in that, The electromagnetic shut-off valve is connected to the air inlet pipe of the air controller, the mass flow controller is connected to the electromagnetic shut-off valve, the vacuum gauge is located at the outlet of the mass flow controller, and the mass flow controller is connected to the air inlet pipe of the etching equipment.

4. The apparatus for reducing wafer loss rate in etching processes as described in claim 1, characterized in that, The ceramic shielding disk is provided with a limiting pin, which is located at a certain distance from the inner circumference edge on the upper surface of the ceramic shielding disk. The limiting pin is used to limit the movement range of the wafer.

5. A method for reducing wafer drop rate in etching processes, applicable to the apparatus for reducing wafer drop rate in etching processes as described in any one of claims 1-4, characterized in that, include: The real-time vacuum value in the ventilation pipeline of the etching equipment is detected by the ventilation controller. When the real-time vacuum value is greater than the first preset value, a vacuum extraction operation is performed on the etching equipment. When the vacuum value is less than the first preset value, gas is introduced into the ventilation pipeline of the etching equipment to make the wafer float. The ceramic shielding disk prevents the floating wafer from deviating from the preset area; After the ventilation controller detects that the real-time vacuum value is greater than the first preset value, it stops ventilation, allowing the wafer to fall.

6. An etching apparatus, characterized in that, Includes etching equipment and the apparatus for reducing wafer loss rate during etching processes as described in any one of claims 1-4; The etching equipment is used to etch wafers, and the device for reducing the wafer drop rate during the etching process is used to eliminate the residual electrostatic adhesion effect on the wafer after the etching process is completed, so that the wafer can be stably removed from the etching equipment.

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