TW201403703A - Etching device and corresponding etching method - Google Patents

Abstract

The invention relates to an etching device and a corresponding etching method. The etching device comprises a reaction chamber, a chip bearing table, a radio frequency generator, an air inlet unit, an air outlet unit and a programmable logic controller (PLC); the PLC is connected with the radio frequency generator and an airflow controller and used for simultaneously conducting circulated control on the radio frequency generator and the airflow controller, so that the etching device can alternatively etch a chip to be etched and form polymers on side walls of grooves and through holes formed in etching. The PLC is used for simultaneously conducting circulated control on the radio frequency generator and the airflow controller, thus being capable of improving the control synchronicity to the radio frequency generator and the airflow controller, and shortening the switching time of the etching stage and the polymer formation stage.

Description

Etching device and corresponding etching method

The present invention relates to the field of semiconductor fabrication, and more particularly to an etching apparatus and a corresponding etching method.

In the field of semiconductor manufacturing technology, especially in the fields of MEMS (Micro Electro Mechanical Systems) and 3D packaging technology, deep via or deep trench etching is generally required for materials such as germanium. For example, in the 3D packaging technology, the germanium substrate needs to be etched to form a deep silicon via (TSV) having a depth of several hundred micrometers, and the aspect ratio of the deep via is much larger than 10.

1 to 3 are schematic cross-sectional views showing an etching process of a deep trench or a deep via hole according to a prior art.

Referring to FIG. 1, a hard mask layer 11 is formed on the surface of the semiconductor substrate 10, a photoresist layer is formed on the surface of the hard mask layer 11, and the photoresist layer is exposed and developed to form a patterned a photoresist layer 12; referring to FIG. 2, the hard mask layer 11 is etched by using the patterned photoresist layer 12 as a mask, so that an opening is formed in the hard mask layer 11 The opening corresponds to a subsequently formed deep trench.

Referring to FIG. 3, the patterned photoresist layer is removed, and the semiconductor substrate 10 is dry etched by using the mask layer 11 having an opening as a mask, and the semiconductor substrate 10 is engraved in the semiconductor substrate 10. The etch forms a deep trench 13 on the sidewall of which the polymer 14 is formed, the polymer 14 is used to protect the deep trench sidewalls, wherein the process of forming the polymer and the etching process are simultaneously performed. Row.

When the depth of the deep trench and the deep via hole reaches several tens of micrometers or even hundreds of micrometers, the aspect ratio of the deep trench and the deep via hole is usually greater than 20 or even 100, and the sidewall is formed as the etching time increases. The amount of polymer is also increasing, and the thickness of the polymer is also increasing. The excessively thick polymer affects the etching gas into the deep trench and the deep via hole for further etching, which reduces the etching rate. .

The problem to be solved by the present invention is to provide an etching device for etching deep trenches or deep via holes and a corresponding etching method, so that sidewalls of deep trenches or deep via holes formed by etching are smooth.

In order to solve the above problems, the technical solution of the present invention provides an etching apparatus, comprising: a reaction chamber, a film stage, a radio frequency generator, an air intake unit, an exhaust unit, a programmable logic controller; Located in the reaction chamber for carrying a substrate to be etched; the air intake unit includes a plurality of intake passages connected to the reaction chamber and a plurality of air flow controllers connected to the intake passages, The gas flow controller controls a source gas and a gas flow rate that are introduced into the reaction chamber; the RF generator plasmaizes the source gas and etches or etches the substrate to be etched using the plasma of the source gas a trench, a sidewall of the via forming a polymer; the exhaust unit is configured to discharge residual gas in the reaction chamber; the programmable logic controller is connected to the RF generator and the airflow controller, and is controlled by the programmable logic At the same time, the RF generator and the air flow controller are controlled in a loop, so that the etching device can alternately etch the etched substrate and form a trench and a via sidewall formed by etching. Compounds.

Optionally, the programmable logic controller sends an analog control signal and a time control signal to the radio frequency generator and the air flow controller, so that the radio frequency generator and the air flow controller are controlled according to the analogy within a time range determined by the time control signal. The signal controls the power of the RF generator and the source gas and flow rate into the reaction chamber.

Optionally, the programmable logic controller sends different analog control signals to the RF generator and the airflow controller during the etching phase and the forming polymer phase, so that the RF generator and the airflow controller are in accordance with the corresponding phase. The analog control signal controls the power of the RF generator and the source gas and flow rate into the reaction chamber.

Optionally, a pressure controller is further included, and the air pressure controller is connected to the exhaust unit, and the pressure in the reaction chamber is controlled by controlling the exhaust amount.

Optionally, the programmable logic controller is further connected to the air pressure controller, and the programmable logic controller simultaneously performs loop control on the radio frequency generator, the air flow controller, and the air pressure controller, so that the etching The device can alternately etch the etched substrate and form a polymer on the trench formed by the etch and the sidewall of the via.

Optionally, the programmable logic controller sends an analog control signal and a time control signal to the radio frequency generator, the air flow controller, and the air pressure controller, so that the radio frequency generator, the air flow controller, and the air pressure controller are determined by the time control signal. The power of the RF generator, the source gas flowing into the reaction chamber, the flow rate, and the gas pressure in the reaction chamber are respectively controlled according to the analog control signal in a time range.

Optionally, the programmable logic controller sends different analog control signals to the RF generator, the airflow controller, and the air pressure controller during an etching phase and a polymer forming phase, so that the RF generator, the airflow controller, The air pressure controller controls the power of the radio frequency generator and the source gas, the flow rate, and the air pressure in the reaction chamber that are introduced into the reaction chamber according to the analog control signal in the corresponding phase.

Optionally, the etching device is a reactive ion etching device, and an inductive coupling isolating A daughter etching device or a capacitive coupling plasma etching device.

Optionally, when the etching device is an inductively coupled plasma etching device, the RF generator includes two RF generating units, wherein the first RF generating unit is connected to an inductor coil located at a top or a sidewall of the reaction chamber. For plasmaizing the source gas, the second RF generating unit is connected to the substrate, so that a bias voltage is applied between the substrate to be etched on the substrate and the plasma of the source gas, so that the plasma is directed toward The surface of the substrate to be etched moves.

Optionally, the air intake passage of the air intake unit includes at least two, one of which is connected to the first gas for etching the substrate to be etched, and the other is connected to the second gas for forming the polymer. a gas, when the etching device is in an etching stage by using the programmable logic controller, opening a gas flow controller corresponding to the first gas, and closing a gas flow controller corresponding to the second gas, so that the first gas is introduced into the reaction In the cavity, and by adjusting the power of the RF generator, the plasma of the first gas is etched to etch the substrate; when the programmable logic controller is used to cause the etching device to be in the polymer forming stage, Closing the air flow controller corresponding to the first gas, opening the air flow controller corresponding to the second gas, so that the second gas is introduced into the reaction chamber, and adjusting the power of the radio frequency generator, so that the plasma of the second gas is etched The sidewalls of the trench form a polymer.

Optionally, the etching device further includes an endpoint determining unit that determines a depth of the etched trench according to the total etch time, and sends a termination signal to the programmable logic controller when the depth of the etched trench reaches a predetermined value. The process of stopping etching and forming a polymer.

The technical solution of the present invention further provides an etching method using the etching device, comprising: applying an etching signal to the programmable logic controller, wherein the programmable logic controller simultaneously controls the RF generator and the airflow The loop control is performed, so that the etching device can alternately etch the etched substrate and form a polymer on the sidewall of the etched trench until the depth of the etched trench reaches a predetermined value, stopping etching and forming. Polymer process.

Optionally, the gas that is introduced into the reaction chamber includes at least a etched silicon wafer. a first gas and a second gas for forming a polymer, wherein the etching device is in an etching stage by using the programmable logic controller, opening a gas flow controller corresponding to the first gas, and closing the gas flow corresponding to the second gas a controller that causes the first gas to pass into the reaction chamber and simultaneously modulates the power of the RF generator such that the plasma of the first gas etches the substrate; and then utilizes the programmable logic controller The etching device is in a polymer forming phase, closing a gas flow controller corresponding to the first gas, opening a gas flow controller corresponding to the second gas, so that the second gas is introduced into the reaction chamber, and simultaneously adjusting the RF generator The power is such that the plasma of the second gas forms a polymer on the sidewalls of the etched trench.

Optionally, the first gas is one of SF ₆ and NF ₃ , and the second gas is one or more of C ₄ F ₈ , C ₄ F ₆ , CHF ₃ , and CH ₂ F ₂ .

Optionally, when the etching device is an inductively coupled plasma etching device, the RF generator includes two RF generating units, wherein the first RF generating unit is connected to an inductor coil located at a top or a sidewall of the reaction chamber. The second RF generating unit is connected to the carrier. When the etching device is in an etching stage, the power of the first RF generating unit ranges from 1000 W to 5000 W, and the power range of the second RF generating unit is 10W~100W; when the etching device is in the polymer forming stage, the power of the first RF generating unit ranges from 500W to 3000W, and the power of the first RF generating unit is smaller than the first RF when the etching stage occurs. The power of the unit, the power of the second RF generating unit ranges from 10W to 100W.

Optionally, the time of the etching phase is 0.5 seconds to 5 seconds.

Optionally, the time for forming the polymer phase is from 0.5 seconds to 5 seconds.

Optionally, the total etching time is used to determine the depth of the etched trench. When the total etch time reaches a certain value, the programmable logic controller simultaneously controls the RF generator, the airflow controller to turn off, etch and form a polymer. stop.

Compared with the prior art, the present invention has the following advantages: the etching device of the embodiment of the invention adopts a programmable logic controller and a radio frequency The living device and the air flow controller are connected, and the programmable logic controller is used to simultaneously perform loop control on the RF generator and the air flow controller, so that the etching device can alternately etch the substrate for etching and The trench formed by etching and the sidewall of the via hole form a polymer, which can improve the synchronization of the control of the RF generator and the air flow controller, and reduce the switching time of the etching phase and the formation of the polymer phase.

10‧‧‧Substrate

11‧‧‧ Hard mask layer

12‧‧‧Photoresist layer

13‧‧‧deep trench

14‧‧‧ polymer

110‧‧‧Reaction chamber

120‧‧‧Sheet

131‧‧‧First RF generating unit

132‧‧‧Second RF generating unit

133‧‧‧Inductance coil

140‧‧‧Air intake unit

141‧‧‧Intake passage

142‧‧‧Airflow controller

150‧‧‧Exhaust unit

160‧‧‧Programmable Logic Controller

210‧‧‧Reaction chamber

220‧‧‧Sheet

231‧‧‧First RF Generator

232‧‧‧Second RF generator

240‧‧‧Air intake unit

241‧‧‧Intake passage

242‧‧‧Airflow controller

250‧‧‧Exhaust unit

260‧‧‧Programmable Logic Controller

270‧‧‧Pneumatic controller

1 to FIG. 3 are schematic cross-sectional structural views of an etching process of a deep trench or a deep via hole according to a prior art; FIG. 4 is a schematic structural view of an etching apparatus according to an embodiment of the present invention; Another schematic diagram of the structure of the etching apparatus; FIG. 6 is a schematic flow chart of the etching method of the embodiment of the present invention.

Since the etching rate of the prior art is low, the inventors have proposed an etching method comprising: etching a plasma etching of a substrate to be etched; forming a polymer phase, forming a trench in the etching, The sidewalls of the vias form a polymer; the etching phase and the forming polymer phase alternate until the deep trench or deep via etching is completed. With the etching method, a very thick polymer is not formed on the sidewalls, and the etching rate is not affected. However, since the plasma etching is not completely anisotropic, the bottom of the deep trench or deep via is etched away from each other while further etching down the bottom of the deep trench or deep via. The sidewalls are such that the sidewalls formed by each etching step are curved, and the rear sidewalls of the polymer form small protrusions, which may reduce the smoothness of the deep trenches or deep via sidewalls. Although theoretically shortening the etching time and forming the polymer phase can improve the smoothness of the deep trench or deep via sidewall, when the etching phase time is too short, the existing etching device is time-controlled. The accuracy is not high, and it takes a certain time to switch from the formation of the polymer phase to the etching phase, resulting in an actual etching time being too short and an etch rate being lowered.

To this end, the embodiment of the present invention first provides an etching device, please refer to the figure. 4, the etching device comprises: a reaction chamber 110, a film stage 120, a radio frequency generator, an air intake unit 140, an exhaust unit 150, a programmable logic controller 160; the wafer stage 120 is located in the reaction chamber 110 is used to carry a substrate to be etched; the air intake unit 140 includes a plurality of air intake passages 141 connected to the reaction chamber 110 and a plurality of air flow controllers 142 connected to the air intake passages 141. The airflow controller 142 controls source gas and gas flow into the reaction chamber 110; the radio frequency generator plasmats the source gas and etches or etches the substrate to be etched using the plasma of the source gas The trench formed by the etch and the sidewall of the via form a polymer; the exhaust unit 150 is connected to the reaction chamber 110 for discharging residual gas in the reaction chamber 110; the programmable logic controller 160 and the RF generator, The airflow controller 142 is connected, and the programmable logic controller 160 is used to simultaneously perform loop control on the RF generator and the airflow controller 142, so that the etching device can alternately etch the substrate to be etched and Etched trench The grooves and the sidewalls of the through holes form a polymer.

In the embodiment of the present invention, the etching device is an inductively coupled plasma etching device, and the RF generator includes a first RF generating unit 131 and a second RF generating unit 132, wherein the first RF generating unit 131 is located The inductor coil 133 on the side wall of the reaction chamber 110 is connected for plasmaizing the source gas that is introduced into the reaction chamber, and the second RF generating unit 132 is connected to the carrier 120 so that the substrate 120 is placed on the stage 120. A bias voltage is applied between the etched substrate and the plasma formed by the source gas to move the plasma toward the surface of the substrate to be etched, so that the plasma can enter the deep trench or the deep via hole for etching, and In order to protect the sidewalls of the deep trench or deep via, it is necessary to form a polymer on the sidewall of the deep trench or deep via, using the bias voltage generated by the second RF generating unit 132 to make a source for forming the polymer. Gas The plasma enters deep trenches or deep vias formed by etching, forming a polymer on the sidewalls of the deep trenches or deep vias.

In other embodiments, the inductor coil is located at the top of the reaction chamber, and the first RF generating unit is connected to an inductor coil located at the top of the reaction chamber, and the inductor coil located at the top of the reaction chamber can also pass the RF signal. The source gas entering the reaction chamber is plasmated.

In other embodiments, the etching device may also be a reactive ion etching device, a capacitively coupled plasma etching device, or the like.

The air intake unit 140 includes a plurality of intake passages 141 connected to the reaction chamber 110. The number of the intake passages 141 is at least two, and one of them passes through the first for etching the substrate to be etched. a gas, the other gas is introduced into the second gas for forming a polymer, and when the etching device is in the etching stage by the programmable logic controller, the gas flow controller corresponding to the first gas is turned on, and the gas is turned off. a gas flow controller corresponding to the second gas, such that the first gas is introduced into the reaction chamber, and by adjusting the power of the RF generator, the substrate to be etched by the plasma of the first gas is etched; The logic controller causes the etching device to be in a polymer forming phase, shutting down the gas flow controller corresponding to the first gas, opening a gas flow controller corresponding to the second gas, so that the second gas passes into the reaction chamber and passes through The power of the RF generator is adjusted, and a plasma of the second gas is used to etch the sidewalls of the trench to form a polymer.

In this embodiment, the etching device includes three intake passages 141, one of which is used to open the first gas, and the first gas is one of SF ₆ and NF ₃ ; the other one is used for Passing in a second gas, the second gas being one of C ₄ F ₈ , C ₄ F ₆ , CHF ₃ , CH ₂ F ₂ ; one of which is used to pass an accompanying gas, such as N ₂ , Ar, O ₂ or the like is used to dilute the reaction gas, increase the etching rate, and the like.

Each of the intake passages 141 is connected to a gas flow controller (MFC) 142. By controlling each of the air flow controllers 142, the gases in each of the corresponding intake passages 141 have different air flows. Therefore, using the gas flow The controller 142 can control the flow of the source gas and the source gas that are introduced into the reaction chamber 110 at different time periods.

The exhaust unit 150 includes a vacuum pump connected to the reaction chamber 110 for discharging unreacted source gas in the reaction chamber 110 and by-product gas generated by the reaction.

The Programmable Logic Device (PLD) 160 mainly includes a Field Programmable Gate Array (FPGA) or a Complex Programmable Logic Device (CPLD). In this embodiment, the programmable logic controller is a complex programmable logic device. Because the complex programmable logic device has better time predictability, it is beneficial to accurately control the time and benefit of the RF generator generating different RF signals. The timing of the different source gases that are passed into the reaction chamber is precisely utilized by the gas flow controller 142.

In the embodiment of the present invention, the programmable logic controller 160 is connected to the radio frequency generator and the airflow controller 142, and can respectively send an analog control signal and a time control signal to the radio frequency generator and the airflow controller 142. The magnitude of the analog control signal sent by the radio frequency generator corresponds to the frequency of the radio frequency signal generated by the radio frequency generator, and the time control signal sent to the radio frequency generator corresponds to the time of the radio frequency signal generated by the radio frequency generator. The magnitude of the analog control signal sent to the airflow controller 142 corresponds to the magnitude of the airflow in the intake passage 141 controlled by the airflow controller 142, and the time control signal sent to the airflow controller 142 corresponds to The ventilation time of the intake passage 141. In this embodiment, the time control signals sent to the radio frequency generator and the airflow controller 142 are equal, and the first radio frequency generating unit 131, the second radio frequency generating unit 132, and the airflow controller 142 are synchronously controlled to make the first The radio frequency generating unit 131, the second radio frequency generating unit 132, and the airflow controller 142 control the power of the radio frequency generator and the source gas and the flow rate into the reaction chamber according to the corresponding analog control signal within a time range determined by the time control signal. And according to the difference of the analog control signals, The etching device is controlled to be in an etch phase or in a polymer forming phase.

In the embodiment of the present invention, the programmable logic controller 160 may also be connected to an external monitoring computer (not shown) for monitoring the etching process and inputting relevant parameters of the entire etching process. For example, the etching phase, the duration of the formation of the polymer phase, and the corresponding operating parameters of the RF generator, the airflow controller 142, and the like in each phase. After the monitoring computer inputs the relevant parameters of the entire etching process, the monitoring computer sets the programmable logic controller 160 so that the analog control signal and the time control signal generated by the programmable logic controller 160 and the newly set entire etching are performed. The relevant parameters of the process correspond.

In this embodiment, since the programmable logic controller 160 is directly connected to the RF generator and the airflow controller 142, the RF power generated by the RF generator and the airflow controlled by the airflow controller 142 can be synchronously controlled, so that the RF When the RF power of the generator is the RF power corresponding to the etching process, the source gas introduced by the air intake unit 140 is also the source gas corresponding to the etching process, and the RF power of the RF generator is corresponding to the polymer forming process. At the time of RF power, the source gas that the air intake unit 140 is connected to is also a source gas corresponding to the formation of the polymer process, thereby avoiding the switching cost of the etching phase and the formation of the polymer phase due to the asynchronous operation of the RF generator and the airflow controller 142. Excessive time makes it impossible to perform effective etching in a part of the etching stage. Therefore, the etching apparatus of the embodiment of the present invention can greatly reduce the switching time of the etching stage and the formation of the polymer stage.

In order to reduce the height of the small protrusions formed during deep trench and deep via etching, and to improve the smoothness of the deep trenches and deep via sidewalls, it is necessary to shorten the time of each etching process and each polymer deposition process. To increase the frequency of switching between the etching process and the polymer deposition process, but since the RF generator and the air flow controller in the prior art etching device are controlled by an external monitoring computer through the serial line, the transmission rate of the serial line Slower, the accuracy of time control is not high, the monitoring computer will control the RF generator and the airflow controller through the serial line. There may be time error, and the minimum time for each etching stage and polymer phase is 0.5. In seconds The slight out-of-synchronization affects the etching process and the process of forming a polymer on the sidewalls, so that deep trenches and deep vias cannot be etched smoothly. The programmable logic controller 160 of the embodiment of the present invention is directly connected to the radio frequency generator and the airflow controller 142. The programmable logic controller 160 directly controls the radio frequency generator and the airflow controller 142, and the frequency generated by the radio frequency generator. The synchronism with the gas introduced into the reaction chamber 110 is higher, and even if the etching time and the time for forming the polymer phase can be as small as 0.5 second, the etching of the substrate can be well performed for etching and etching. The deep through holes and deep trenches measure the sidewalls to form a polymer.

In other embodiments, the programmable logic controller is coupled to the RF generator and the airflow controller, and continuously transmits different analog control to the RF generator and the airflow controller during the etching phase and the forming polymer phase, respectively. The signal causes the RF generator and the airflow controller to control the power of the RF generator and the source gas and flow into the reaction chamber according to the analog control signal in the corresponding phase. Depending on the analog control signal, the etching device can be controlled to be in an etch phase or in a polymer forming phase.

In the embodiment of the present invention, the etching device further includes an endpoint determining unit (not shown), the endpoint determining unit is connected to the programmable logic controller and the monitoring computer, and the monitoring computer can send the total etching time to The endpoint determining unit determines the depth of the etched trench according to the total etch time. When the depth of the etched trench reaches a predetermined value, the endpoint determining unit sends a termination signal to the programmable logic controller, the programmable The logic controller stops sending the analog control signal and the time signal to the RF generator and the air flow controller to stop the etching and forming the polymer.

Another embodiment of the present invention provides another etching apparatus. Referring to FIG. 5, the etching apparatus includes a reaction chamber 210, a wafer stage 220, a first RF generator 231, a second RF generator 232, and an intake air. The unit 240, the exhaust unit 250, the programmable logic controller 260, the air pressure controller 270; the wafer stage 220 is located in the reaction chamber 210 for carrying the substrate to be etched; The air intake unit 240 includes a plurality of air intake passages 241 connected to the reaction chamber 210 and a plurality of air flow controllers 242 connected to the air intake passages 241, and the air flow controller 242 is used to control the access to the reaction chamber 210. Source gas and gas flow rate; the first RF generator 231 plasmas the source gas and generates a bias voltage by the second RF generator 232 to etch the source gas plasma to etch the substrate Or forming a polymer in the groove formed by etching, the sidewall of the through hole; the exhaust unit 250 is connected to the reaction chamber 210 for discharging residual gas in the reaction chamber 210, and the gas pressure controller 270 and the exhaust gas The unit 250 is connected to control the pressure in the reaction chamber by controlling the amount of exhaust gas; the programmable logic controller 260 and the first RF generator 231, the second RF generator 232, the air flow controller 242, and the air pressure controller 270 Connected, using the programmable logic controller 260 to perform loop control on the first RF generator 231, the second RF generator 232, the airflow controller 242, and the air pressure controller 270 simultaneously, so that the etching device can Alternatively treat the substrate is etched and etching trenches formed by etching, the through-hole sidewall forming polymer.

Since the pressure of the reaction chamber required for the etching phase or the formation of the polymer phase may be different, when the gas pressure required for the reaction chamber 210 is large, the gas pressure controller 270 is used to control the exhaust unit 250 to reduce the unit time. The amount of residual gas discharged from the exhaust unit 250, when the required air pressure of the reaction chamber 210 is small, the exhaust unit 250 is controlled by the air pressure controller 270 to increase the residual of the exhaust unit 250 per unit time. The amount of gas.

In this embodiment, the programmable logic controller 260 sends an analog control signal and a time control signal to the first RF generator 231, the second RF generator 232, the airflow controller 242, and the air pressure controller 270, so that the first The RF generator, the second RF generator, the airflow controller, and the air pressure controller synchronously control the power of the RF generator, the source gas flowing into the reaction chamber, and the source gas according to the analog control signal within a time range determined by the time control signal, Flow rate and air pressure in the reaction chamber.

In other embodiments, the programmable logic controller continuously transmits different analogies to the first RF generator, the second RF generator, the airflow controller, and the air pressure controller during the etching phase and the polymer formation phase. Controlling the signal such that the first RF generator, the second RF generator, the airflow controller, and the air pressure controller control the power of the RF generator and the source gas, the flow rate and the flow into the reaction chamber according to the analog control signal in corresponding stages The pressure inside the reaction chamber.

The embodiment of the present invention further provides an etching method using the above etching apparatus. Referring to FIG. 6 , a schematic flowchart of an etching method according to an embodiment of the present invention includes: Step S101 : applying an etching signal to the a programmable logic controller that simultaneously performs loop control on the RF generator and the airflow controller, so that the etching device can alternately etch the substrate and etch the trench The sidewall forms a polymer; in step S102, when the depth of the etched trench reaches a predetermined value, the process of etching and forming the polymer is stopped.

The etching method is used to etch a trench or a via hole on a substrate to be etched, in particular for etching to form a deep trench or a deep via having a depth greater than 1 micrometer.

In this embodiment, the substrate to be etched is a ruthenium substrate, and the etch device is an inductively coupled plasma etch device.

Referring to FIG. 4, when the etching device is in an etching stage, the power of the first RF generating unit 131 ranges from 1000 W to 5000 W, and the power of the second RF generating unit 132 ranges from 10 W to 100 W. The gas of the reaction chamber 110 includes a first gas which is one of SF ₆ and NF ₃ , and the accompanying gas is N ₂ , Ar, etc., and the radio frequency signal generated by the first radio frequency generating unit is used to make A source gas such as SF ₆ , NF ₃ , N ₂ , or Ar forms a plasma, and the substrate to be etched is etched by the plasma to form a trench or a sidewall. Since the etching phase and the polymer forming phase are alternated, the trench or via sidewall of the polymer inhibits plasma from etching to the sidewall, and the plasma can only etch the bottom of the trench or via. The sidewalls without the polymer at the bottom of the trench or via are etched to ensure anisotropy throughout the etch process. Since the switching time of the etching apparatus in the etching stage and the polymer forming stage is short in the etching apparatus of the embodiment of the invention, the time of each etching stage and the formation of the polymer stage can also be short, the time of the one etching stage. The range is from 0.5 second to 5 seconds. In this embodiment, the time of one etching phase is 2 seconds.

When the etching device is in the polymer forming stage, the power of the first RF generating unit 131 ranges from 500 W to 3000 W, and the power of the first RF generating unit is less than the power of the first RF generating unit in the etching stage. The power of the second RF generating unit 132 ranges from 10 W to 100 W, and the gas that passes into the reaction chamber 110 includes a second gas and an accompanying gas, and the second gas is C ₄ F ₈ , C ₄ F ₆ , CHF ₃ , One or more of CH ₂ F ₂ , and the accompanying gas is N ₂ , Ar, O ₂ or the like. Using a radio frequency signal generated by the first radio frequency generating unit to cause a source gas such as C ₄ F ₈ , C ₄ F ₆ , CHF ₃ , CH ₂ F ₂ , N ₂ , Ar, O _{2 to} form a plasma, using the plasma pair The exposed sidewalls and the bottom of the one-step etching phase form a polymer. Since the polymer located at the bottom of the trench or via is easily removed in a subsequent etching stage, the polymer located on the sidewall prevents the plasma from being etched in the sidewall. Etching is performed to ensure anisotropy throughout the etching process. Since the etching time of the etching apparatus of the embodiment of the present invention in the etching stage and the polymer forming stage is short, the time of each etching stage and the formation of the polymer stage can also be short, and the one forming the polymer stage can be short. The time range is from 0.5 second to 5 seconds. In this embodiment, the time for forming one polymer phase is 2 seconds. Wherein, the time for forming the polymer phase may be the same as or different from the etching phase. Moreover, since the etching time and the time for forming the polymer phase are short, the height of the protrusion formed by the sidewall can be reduced, and the smoothness of the sidewall of the deep trench or deep via formed by etching can be improved.

In this embodiment, when the monitoring computer sends an etch signal to the programmable logic controller, the programmable logic controller starts to work, and the programmable logic controller sends the RF generator and the airflow controller respectively. Analog control signal and time control signal, first described The etching device enters an etching stage, and the substrate to be etched is etched. After etching for 2 seconds, the programmable logic controller issues analog control signals and time control signals to the RF generator and the air flow controller respectively. The etching device enters a polymer forming stage, and after forming a polymer on the sidewall of the etching trench to form a polymer for 2 seconds, the programmable logic controller separately sends an analog control signal and time to the RF generator and the airflow controller. The control signal causes the etching device to switch to the etching stage again for etching, so that the etching device can alternately etch the substrate to etch and form a polymer on the sidewall of the etched trench.

The endpoint determining unit determines the depth of the etched trench according to the total etch time. When the depth of the etched trench reaches a predetermined value, the endpoint determining unit sends a termination signal to the programmable logic controller, the programmable logic The controller stops sending the analog control signal and the time signal to the RF generator and the air flow controller to stop the etching and forming the polymer.

In other embodiments, the programmable logic controller is connected to the RF generator, the air flow controller, and the air pressure controller, and the programmable logic controller simultaneously performs the RF generator, the air flow controller, and the air pressure controller. The loop control enables the etching apparatus to alternately etch the etched substrate and form a polymer on the trench formed by the etch and the sidewall of the via.

In summary, the etching apparatus of the embodiment of the present invention uses a programmable logic controller to be connected to the RF generator and the air flow controller, and uses the programmable logic controller to simultaneously perform loop control on the RF generator and the air flow controller. The etching device can alternately etch the etched substrate and form a polymer on the trench formed by the etch and the sidewall of the via hole, thereby improving the synchronization of the RF generator and the airflow controller, and reducing the engraving. The switching time of the etch phase and the formation of the polymer phase.

The present invention has been disclosed in the preferred embodiments as described above, but it is not intended to limit the invention, and the present invention may be utilized by the method and technical contents disclosed above without departing from the spirit and scope of the invention. The technical solution makes possible changes and modifications, and therefore, the content of the technical solution according to the present invention is the same as the above without departing from the technical solution of the present invention. Any simple modifications, equivalent changes, and modifications made by the embodiments are within the scope of the present invention.

110‧‧‧Reaction chamber

120‧‧‧Sheet

131‧‧‧First RF generating unit

132‧‧‧Second RF generating unit

133‧‧‧Inductance coil

140‧‧‧Air intake unit

141‧‧‧Intake passage

142‧‧‧Airflow controller

150‧‧‧Exhaust unit

160‧‧‧Programmable Logic Controller

Claims (18)

An etching apparatus comprising: a reaction chamber, a film stage, an RF generator, an air intake unit, an exhaust unit, and a programmable logic controller; wherein the wafer stage is located in the reaction a cavity for carrying a substrate to be etched; the air intake unit includes a plurality of air intake passages connected to the reaction chamber and a plurality of air flow controllers connected to the air intake passage, The air flow controller controls a source gas and gas flow into the reaction chamber; the RF generator plasmaizes the source gas and etches the substrate to be etched using the plasma of the source gas Or forming a polymer in the trench formed by the etching, the sidewall of the via hole; the exhaust unit is configured to discharge residual gas in the reaction chamber; the programmable logic controller and the RF generator, the airflow control Connected to the RF generator and the airflow controller by the programmable logic controller, so that the etching device can alternately etch the substrate for etching and etching Ditch formed by eclipse A through hole formed in the side wall polymers. The etching apparatus of claim 1, wherein the programmable logic controller sends an analog control signal and a time control signal to the radio frequency generator and the air flow controller, so that the radio frequency generator and the air flow control The controller controls the power of the RF generator and the source gas and the flow rate into the reaction chamber according to the analog control signal within a time range determined by the time control signal. The etching apparatus of claim 1, wherein the programmable logic controller supplies the RF generator to the RF stage during an etching phase and a polymer formation phase. The controller sends different analog control signals, so that the RF generator and the airflow controller control the power of the RF generator and the source gas and flow into the reaction chamber according to the analog control signal in a corresponding phase. The etching apparatus of claim 1, further comprising a gas pressure controller connected to the exhaust unit to control the pressure in the reaction chamber by controlling the amount of exhaust gas. The etching apparatus of claim 4, wherein the programmable logic controller is further connected to the air pressure controller, and the programmable logic controller simultaneously uses the radio frequency generator, the air flow controller, The air pressure controller performs loop control so that the etching device can alternately etch the etched substrate and form a polymer on the trench formed by the etch and the sidewall of the via. The etching apparatus of claim 5, wherein the programmable logic controller sends an analog control signal and a time control signal to the radio frequency generator, the air flow controller, and the air pressure controller, so that the radio frequency The generator, the airflow controller, and the air pressure controller respectively control the power of the RF generator, the source gas flowing into the reaction chamber, and the source gas, according to the analog control signal, within a time range determined by the time control signal, Flow rate and air pressure in the reaction chamber. The etching apparatus of claim 5, wherein the programmable logic controller sends different signals to the RF generator, the airflow controller, and the air pressure controller during an etching phase and a polymer forming phase. Analogizing the control signal such that the RF generator, the airflow controller, and the air pressure controller are in accordance with the class in a corresponding phase The control signal controls the power of the RF generator and the source gas, the flow rate, and the gas pressure in the reaction chamber that are introduced into the reaction chamber. The etching device of claim 1, wherein the etching device is a reactive ion etching device, an inductively coupled plasma etching device or a capacitively coupled plasma etching device. The etching device of claim 8, wherein the etching device is an inductively coupled plasma etching device, wherein the RF generator comprises two RF generating units, wherein a first RF generating unit is located The inductive coil of the top or side wall of the reaction chamber is connected to plasma the source gas, and a second RF generating unit is connected to the substrate, so that the substrate to be etched on the substrate is There is a bias voltage between the plasmas of the source gas to move the plasma toward the surface of the substrate to be etched. The etching apparatus of claim 1, wherein the intake passage of the air intake unit comprises at least two, one of which is connected to the first gas for etching the substrate to be etched, and the other Passing a second gas for forming a polymer, when the etch device is in an etch phase by using the programmable logic controller, opening a gas flow controller corresponding to the first gas, and closing the second gas corresponding a gas flow controller, such that a first gas is introduced into the reaction chamber, and by adjusting a power of the RF generator, the plasma of the first gas is etched to be etched; when the programmable The logic controller causes the etching device to be in a polymer forming phase, shutting down the gas flow controller corresponding to the first gas, opening a gas flow controller corresponding to the second gas, allowing the second gas to pass into the reaction chamber, and passing Adjust the RF transmission The power of the burner causes the plasma of the second gas to form a polymer on the sidewalls of the etched trench. The etching apparatus of claim 1, wherein the etching apparatus further comprises an end point determining unit for determining the depth of the etching trench according to the total etching time, when the depth of the etching trench reaches a predetermined value. , a process of issuing a termination signal to the programmable logic controller to stop etching and forming a polymer. An etching method using the etching apparatus according to claim 1, wherein the etching signal is applied to the programmable logic controller, and the programmable logic controller simultaneously applies the RF The generator and the airflow controller perform loop control, so that the etching device can alternately etch the etched substrate and form a polymer on the sidewall of the etched trench until the depth of the etched trench reaches a predetermined level Value, the process of stopping etching and forming a polymer. The etching method of claim 12, wherein the gas introduced into the reaction chamber comprises at least a first gas for etching the tantalum wafer and a second gas for forming a polymer, The programmable logic controller causes the etching device to be in an etching stage, opening a gas flow controller corresponding to the first gas, and closing a gas flow controller corresponding to the second gas, so that the first gas is introduced into the reaction chamber, and At the same time, by adjusting the power of the RF generator, the plasma of the first gas is etched to etch the substrate; then the programmable logic controller is used to make the etching device in the polymer forming phase, and the etching device is turned off. a gas flow controller corresponding to the first gas, opening a gas flow controller corresponding to the second gas, so that the second gas is introduced into the reaction chamber, and simultaneously adjusting the power of the RF generator to make the second gas is quarantined The daughter body forms a polymer on the sidewall of the etched trench. The etching method of claim 13, wherein the first gas is one of SF ₆ and NF ₃ , and the second gas is C ₄ F ₈ , C ₄ F ₆ , CHF ₃ , CH ₂ F ₂ one or more of them. The etching method of claim 12, wherein the etching device is an inductively coupled plasma etching device, the RF generator comprising two RF generating units, wherein the first RF generating unit is located in the reaction The first RF generating unit is connected to the carrier, and the first RF generating unit has a power range of 1000W. ~5000W, the power of the second RF generating unit ranges from 10W to 100W; when the etching device is in the polymer forming stage, the power of the first RF generating unit ranges from 500W to 3000W, The power of the first radio frequency generating unit is smaller than the power of the first radio frequency generating unit in the etching phase, and the power of the second radio frequency generating unit ranges from 10 W to 100 W. The etching method according to claim 12, wherein the etching period is from 0.5 second to 5 seconds. The etching method according to claim 12, wherein the time for forming the polymer phase is from 0.5 second to 5 seconds. The etching method of claim 12, wherein the total etching time is used to determine the depth of the etching trench, and when the total etching time reaches a certain value, the programmable logic The controller simultaneously controls the RF generator, the airflow controller is turned off, and the process of etching and forming the polymer is stopped.