Patent Application
20220115248
The present invention relates to an etching device using an etching chamber, and more particularly, to an etching device using an etching chamber with improved etching performance.
A silicon nitride film has been used as a representative insulating film in a semiconductor manufacturing process. The silicon nitride film has a structure in which the silicon nitride film is in contact with a silicon oxide film, a polysilicon film, a silicon wafer surface, or the like, and is deposited by a chemical vapor deposition (CVD) process and removed by a dry etching and a wet etching.
The dry etching is performed in a vacuum state mainly by putting a fluorine-based gas and an inert gas. However, the dry etching has a limit to commercial use because a device for performing the dry etching is expensive. Therefore, the wet etching using phosphoric acid is widely used rather than the dry etching. Specifically, in the wet etching, a desired target layer is selectively etched from an object (substrate, or the like) by a chemical reaction of an etchant, and depending on required characteristics, an etching degree, or the like, an etchant having a composition ratio corresponding thereto can be easily mixed to perform the etching. Therefore, compared to the dry etching, it is possible to provide improved work compatibility. Moreover, it is possible to process many objects at once, and thus, the device is inexpensive. However, in the wet etching, a portion of the etchant is vaporized during the etching. Therefore, a temperature of the object may be lowered by heat of the vaporization, a concentration of the etchant is difficult to control due to the vaporization of the etchant, and thus, a critical dimension (CD) loss occurs. Accordingly, in order to keep the concentration of the etchant constant, currently, a large amount of deionized water and etchant are added to an etching tank to etch the object, and in this case, an economic loss is large due to the addition of the large amount of deionized water and etchant.
Therefore, inventors of the present invention have studied to keep the concentration of the etchant constant and have completed the present invention by finding that when pressurizing an etchant storage chamber and/or an etching chamber, the vaporization of the etchant can be prevented, and thus, a selectivity of the silicon nitride film to the silicon oxide film can be remarkably improved.
In this regard, Korean Patent No. 10-0691479 (Feb. 28, 2007) discloses an etching device for a large-area substrate.
The present invention is directed to providing an etching device using an etching chamber with improved etching performance.
One aspect of the present invention provides an etching device using an etching chamber, including an etchant storage chamber in which an etchant is stored, a connection unit communicating with the etchant storage chamber, an etching chamber which communicates with the etchant storage chamber through the connection unit and in which an object is etched, and a pressurization maintaining unit configured to maintain at least one of the etchant storage chamber and the etching chamber in a pressurized atmosphere.
The pressurization maintaining unit may include at least one of a first pressurization maintaining unit configured to adjust a pressure of the etchant storage chamber and a second pressurization maintaining unit configured to adjust a pressure of the etching chamber.
The first pressurization maintaining unit may include a first pressurization unit configured to maintain the etchant storage chamber at a set pressure, a temperature control unit configured to control a temperature inside the etchant storage chamber, and a first exhaust unit configured to exhaust a gas inside the etchant storage chamber to an outside.
The second pressurization maintaining unit may include a second pressurization unit configured to maintain the etching chamber at a set temperature and a second exhaust unit configured to exhaust a gas inside the etchant chamber to an outside.
The second exhaust unit may exhaust the gas inside the etching chamber to the outside to generate a pressure difference between the etching chamber and an inside of the etchant storage chamber.
The connection unit may include an etchant moving portion configured to move the etchant from the etchant storage chamber to the etching chamber, a selective blocking unit provided in the etchant moving portion to selectively block the etchant moving portion, and an etchant supply unit configured to promote movement of the etchant.
The etching chamber may include a mounting table on which the object is placed and an etching performance improvement unit provided in the mounting table to improve etching performance of the object.
The etching chamber may include a cup portion in which an accommodation portion is formed therein, and the mounting table may be rotatably provided above the cup portion.
The etching chamber may include a first chamber in which the cup portion is disposed in an internal pressure chamber, and a second chamber provided to be openable or closeable on one side of the first chamber and having an etchant inlet formed to supply the etchant into the second chamber.
The cup portion may include a support placed on a bottom surface of the pressure chamber.
A rotating shaft, which forms a vertical rotation center and to which a rotational driving force from a rotation driving unit is transmitted, may be provided on a lower portion of the mounting table.
The rotating shaft may vertically pass through a first fastening portion of the first chamber and may be provided with a first sealing member inserted into the first fastening portion to surround the rotating shaft in a state of being pressed against the rotating shaft in a rotation direction of the rotating shaft.
The first sealing member may include a first lip portion protruding from an inner peripheral surface to be pressed against the rotating shaft obliquely in a radial direction, and the first lip portion may be provided as one or more first lip portions arranged in a vertical direction.
The etching performance improvement unit may be recessed so that the object is placed thereon in a state of being inserted and immersed in the etchant.
The etching performance improvement unit may include a seating surface formed along an edge of the etching performance improvement unit so that the object is placed thereon and a stepped portion formed along the edge of the seating surface to accommodate the etchant above the object.
The mounting table may include a passage passing through the mounting table vertically.
A raising/lowering unit configured to raise or lower the object may be further provided, the object is located above the mounting table when the raising/lowering unit is raised, and the object is placed on the etching performance improvement unit when the raising/lowering unit is lowered.
The raising/lowering unit may include a body liftable or lowerable from a lower portion of the cup portion, and a support pin which protrudes upward from the body, is liftable or lowerable through the passage, and supports a lower portion of the object.
The body may include a raising/lowering pin to which a raising/lowering driving force is transmitted from a raising/lowering driving unit.
The raising/lowering pin may vertically pass through a second fastening portion of the first chamber and may be provided with a second sealing member which protrudes from a lower portion of the body, is inserted into the second fastening portion, and surrounds the raising/lowering pin in a state of being pressed against the raising/lowering pin in a width direction of the raising/lowering pin.
The second sealing member may include a first lip portion protruding from an inner peripheral surface to be pressed against the raising/lowering pin obliquely in the width direction, and the second lip portion may be provided as one or more second lip portions arranged in a vertical direction.
A cleaning unit, which cleans the etchant after etching is completed, may be provided in the etching chamber.
The cleaning unit may include a supply line connected to an inside of the etching chamber, and a cleaning water supply unit configured to supply cleaning water through the supply line.
The etchant storage chamber and the etching chamber may be disposed to communicate with each other inside an etching unit sealed from the outside, and the inside of the etching unit may be maintained in a pressurized atmosphere.
The pressurized atmosphere may be maintained at 0.1 bar to 10 bar, and the etching chamber may include a discharge unit for exhausting the etchant supplied into the etching chamber to the outside.
The etching device using an etching chamber may further include a storage unit for storing the object, and the storage unit may consecutively move unetched objects to the etching chamber 130 one by one to perform etching and may consecutively move etched objects to the outside of the etching chamber.
The etching chamber may be a batch type chamber in which a plurality of objects are disposed and etched at the same time, or the etching chamber may be a single wafer type chamber in which the etchant is sprayed onto the object and the object is etched.
The etchant may selectively use at least one or a mixture of one or more of HF, NHO3, H2O2, IPA, NH4OH, H2O, H3PO4, and H2SO4.
In an etching device using an etching chamber according to the present invention, it is possible to prevent vaporization of an etchant by pressurizing an etchant storage chamber and/or an etching chamber. Therefore, a concentration of the etchant is kept constant, and thus, an etching selectivity can be remarkably improved.
In addition, since the concentration of the etchant is kept constant due to the pressurization, additional deionized water and an additional input of the etchant are not required to maintain the concentration. Accordingly, it is possible to improve a product yield and reduce consumption of the etchant.
Hereinafter, the present invention will be described in more detail. However, the present invention may be implemented in various different forms, and the present invention is not limited to embodiments described herein and is only defined by claims to be described below. In addition, terms used in the present invention are only used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the entire specification of the present invention, “including” a certain component means that other components may be further included, rather than excluding other components, unless specifically stated to the contrary.
As illustrated in
First, an etchant L is stored in the etchant storage chamber 110, and an etchant accommodation space is formed inside the etchant storage chamber 110. Here, the etchant storage chamber 110 may be made of a metal (stainless steel or the like), and an inside of the etchant storage chamber 110 may be coated with a separate material (Teflon or the like).
One end of the connection unit 120 communicates with the inside of the etchant storage chamber 110, the other end thereof communicates with an inside of the etching chamber 130 described below, and the etchant L is moved through the connection unit 120 during an etching process. The connection unit 120 may include an etchant moving portion 121 through which the etchant L is moved from the etchant storage chamber 110 to the etching chamber 130 described below, a selective blocking unit 122 which is provided in the etchant moving portion 121 and selectively blocks the etchant moving portion 121, and an etchant supply unit 123 for promoting movement of the etchant L.
The etching chamber 130 communicates with the etchant storage chamber 110 through the connection unit 120, and an accommodation space in which an etching object (substrate or the like) W is disposed is formed inside the etching chamber 130. A mounting table 131 may be provided inside the etching chamber 130, and an etching performance improvement unit for improving etching performance of the object W may be formed on an upper portion of the mounting table 131.
The object W may be placed on the mounting table 131 in the etching chamber 130, and the mounting table 131 may be installed to be horizontally rotatable inside the etching chamber 130 and rotated at a constant speed by a driving force of a driving unit (not illustrated).
The etching performance improvement unit is for improving the etching performance of the object W disposed on an upper surface of the mounting table 131, and the etching performance improvement unit may be formed to protrude from an upper end of the mounting table 131. In more detail, the etching performance improvement unit may be formed along a periphery of the mounting table 131, and the etching performance improvement unit may protrude upward from the mounting table 131. The etching performance improvement unit may be formed to have a width greater than a vertical thickness of the object W. In this way, the etching performance improvement unit forms an accommodation space above the mounting table 131, and thus, the object W placed on the mounting table 131 may be positioned lower than the upper end of the etching performance improvement unit.
In this state, when the etchant L is supplied to the upper portion of the mounting table 131, the etchant L is accommodated in the accommodation space formed by the etching performance improving unit, and the etching object W may be etched in a state of being immersed in the etchant L at a predetermined level.
In addition, the etching chamber 130 may further include a discharge unit (not illustrated) for discharging the etchant L supplied into the etching chamber 130 to the outside, and the discharge unit may include a discharge line connected to the inside of the etching chamber 130 and a discharge driving unit which is connected to the discharge line to provide a discharge pressure.
In addition, an information display gauge may be installed outside the etching chamber 130 and the etchant storage chamber 110 to display an internal pressure, a temperature, or the like to the outside.
In addition, the etching chamber 130 may include a cleaning unit 160 for cleaning the etchant L after the etching is completed, and the cleaning unit 160 may include a supply line 161 which is connected to the inside of the etching chamber 130 and a cleaning water supply unit 162 which supplies a cleaning water through the supply line 161.
In addition, the etching device using an etching chamber according to one embodiment of the present invention may further include a storage unit (not illustrated) for storing the object W.
The storage unit may consecutively move the unetched objects W to the etching chamber 130 one by one to perform etching and may consecutively move the etched objects W to the outside of the etching chamber 130.
In addition, the etching chamber 130 may have a batch type structure in which a plurality of objects W are disposed and etched at the same time, or a single wafer type structure in which the etchant L is sprayed onto the object W and the object W is etched.
The pressurization maintaining unit is for maintaining at least one of the etchant storage chamber 110 and the etching chamber 130 in a pressurized atmosphere during the etching process and may include at least one of a first pressurization maintaining unit for adjusting a pressure of the etchant storage chamber 110 and a second pressurization maintaining unit for adjusting a pressure of the etching chamber 130.
In this case, as shown in
The first pressurization unit 141 may have a pressure control function for maintaining the internal pressure of the etching chamber 130 at a set process pressure, and to this end, a pressure sensing unit (not illustrated) for measuring the internal pressure of the etchant storage chamber 110 may be electrically connected to the first pressurization unit 141.
In addition, the temperature control unit 142 may have a temperature control function for maintaining the internal temperature at a set process temperature, and to this end, a temperature sensing unit (not illustrated) for measuring the internal temperature of the etchant storage chamber 110 may be electrically connected to the temperature control unit 142. For example, the temperature control unit 142 may include a heating member 142a which is installed in the inner space of the etchant storage chamber 110 and a power supply unit (not illustrated) which applies power to the heating member 142a. In this case, a container for accommodating the etchant L may be disposed inside the etchant storage chamber 110, and the heating member 142a may be installed in contact with the outside of the container.
The second pressurization maintaining unit may include a second pressurization unit 151 for maintaining the etching chamber 130 at a set pressure, and a second exhaust unit 152 for discharging the gas inside the etching chamber 130 to the outside.
The second pressurization unit 151 may have a structure capable of supplying compressed gas into the etching chamber 130 and may have a pressure control function for maintaining the internal pressure of the etching chamber 130 at a set process pressure.
The first pressurization unit 141 may have a pressure control function for maintaining the internal pressure of the etching chamber 130 at a set process pressure, and to this end, a pressure sensing unit (not illustrated) for measuring the internal pressure of the etchant storage chamber 110 may be electrically connected to the first pressurization unit 141.
In addition, the temperature control unit 142 may have a temperature control function for maintaining the internal temperature at a set process temperature, and to this end, a temperature sensing unit (not illustrated) for measuring the internal temperature of the etchant storage chamber 110 may be electrically connected to the temperature control unit 142.
The second exhaust unit 152 may discharge the gas inside the etching chamber 130 to the outside during the etching process to generate a pressure difference between the inside of the etchant storage chamber 110 and the outside thereof.
The pressurization maintaining units may form a pressurized atmosphere inside the etchant storage chamber 110 and the etching chamber 130 during the etching process, and at this time, the pressurized atmosphere may be maintained at 0.1 bar to 10 bar.
Meanwhile, the etchant storage chamber 110 and the etching chamber 130 may be disposed to communicate with each other inside an etching unit sealed from the outside, and the inside of the etching unit may be maintained in a pressurized atmosphere.
Hereinafter, an operation of the etching device using an etching chamber according to one embodiment of the present invention will be described with reference to
First, the first pressurization unit 141 and the temperature control unit 142 are driven to pressurize the inside of the etchant storage chamber 110 in which the etchant L is accommodated at the set process pressure, and at the same time, maintain the process temperature.
In this way, in a process of increasing an internal temperature of the etchant storage chamber 110 to the set process temperature, the first exhaust unit 143 may be driven to exhaust the internal gas of the etchant storage chamber 110 to the outside.
Thereafter, the second pressurization unit 151 is driven to pressurize the inside of the etching chamber 130 in which the object W is disposed at the set process pressure so that the internal pressure in the etching chamber 130 is the same as the internal pressure of the etchant storage chamber 110.
When the internal pressures of the etchant storage chamber 110 and the etching chamber 130 reach the set pressure, the selective blocking unit 122 of the etchant moving portion 121 is opened to open the etchant moving portion 121. In this case, the inside of the etchant storage chamber 110 may communicate with the inside of the etching chamber 130 by the opening of the etchant moving portion 121, and the gas inside the etching chamber 130 may be exhausted to the outside by driving the second exhaust unit 152. In this process, a pressure difference between the etchant storage chamber 110 and the etching chamber 130 is generated due to an exhaust operation of the second exhaust unit 152, and the etchant L stored inside the etchant storage chamber 110 is introduced into the etching chamber 130 through the etchant moving portion 121 by the pressure difference to etch the object W.
The etching device using an etching chamber according to another embodiment of the present invention will be described with reference to
The etching device includes an etchant storage chamber 300 in which the etchant L is stored and a single wafer type or batch type etching chamber 400 in which the etching object W is etched, and the etchant storage chamber 300 and the etching chamber 400 are connected to each other so that the etchant L is moved but are sealed from the outside. Moreover, when the object W is etched, the inside of at least one of the etchant storage chamber 300 and the etching chamber 400 may be maintained in a pressurized atmosphere.
First, the etching device using an etching chamber which does not include the etching unit 200 will be described with reference to
In one embodiment of the present invention, the etching device using an etching chamber may include the etchant storage chamber 300 in which the etchant L is stored and the single wafer type etching chamber 400 in which the object W is etched. In this case, the etchant storage chamber 300 and the etching chamber 400 may be connected to each other so that the etchant L is moved and may be sealed from the outside. Meanwhile, the connection may be performed through a connection unit 500, and at this time, the connection unit 500 is not limited as long as the etchant L may be moved, the etchant storage chamber 300 and the etching chamber 400 may be pressed against each other so that a portion of the contact surface may be opened or closed through opening or closing and preferably may be connected by a pipe as illustrated in
In addition, the outside may mean all spaces except the insides of the etchant storage chamber 300 and the etching chamber 400, and there is no restriction on the form of sealing from the outside, but preferably, as illustrated in
In one embodiment of the present invention, the etching device 100 using an etching chamber that does not include the etching unit 200 may pressurize each of the etchant storage chamber 300 and/or the etching chamber 400, and in this case, the etching device 100 using the etching chamber for the pressurization may further include a pressurization unit 700 and an exhaust unit 800 for discharging pressurized air. In this case, the pressurization unit 700 and the exhaust unit 800 may be connected to each of the etchant storage chamber 300 and the etching chamber 400, the connection may be preferably performed through a pipe, and a valve may be installed in the pipe so that a degree of pressurization may be easily controlled.
Next, the etching device 100 using an etching chamber which includes the etching unit 200 will be described with reference to
Hereinafter, detailed descriptions of portions overlapping with portions in the etching device 100 using an etching chamber which does not include the etching unit 200 are omitted, but the above descriptions may be applied in the same manner even when descriptions are omitted in the etching device 100 using an etching chamber including the etching unit 200.
In one embodiment of the present invention, the etching device 100 using the etching chamber may further include the etching unit 200 which accommodates the etchant storage chamber 300 and the etching chamber 400 and is sealed from the outside. In this case, one of the etchant storage chamber 300 and the etching chamber 400 may be opened, and when the object W is etched, the entire inside of the etching unit 200 may be maintained in a pressurized atmosphere.
In one embodiment of the present invention, the etching device 100 using an etching chamber for pressurization may further include the pressurization unit 700 and the exhaust unit 800 for discharging the pressurized air. In this case, each of the pressurization unit 700 and the exhaust unit 800 may be connected to the etching unit 200, the connection may be preferably connected through a pipe, and a valve may be installed in the pipe so that the degree of pressurization may be easily controlled. That is, in the etching device 100 using an etching chamber which includes the etching unit 200, the etchant storage chamber 300 and the etching chamber 400 are accommodated in the etching unit 200 and formed as a system and thus have a configuration of pressurizing the entire inside of the etching unit 200. Accordingly, in order to pressurize the etchant L, one of the etchant storage chamber 300 and the etching chamber 400 may be open.
Meanwhile, the etchant L has a property of a liquid, and thus, preferably, the etchant storage chamber 300 and the etching chamber 400 may have an open upper portion.
Hereinafter, contents which may be applied to both the etching device 100 using the etching chamber which does not include the etching unit 200 and the etching device 100 using the etching chamber which includes the etching unit 200 will be described in detail.
In one embodiment of the present invention, in the etching device 100 using an etching chamber, the etchant L stored in the etchant storage chamber 300 may be moved to the etching chamber 220 and the object W may be etched inside the etching chamber 400. That is, the etchant L may be moved to both the etchant storage chamber 300 and the etching chamber 400 but preferably may be moved in one direction from the etchant storage chamber 300 to the etching chamber 400. Meanwhile, as illustrated in
In the mounting table 410 according to one embodiment of the present invention, after the object W is placed on a support pin (not illustrated), the object W may be fixed (chucked) using a chuck (not illustrated).
Meanwhile, as illustrated in
In one embodiment of the present invention, the etching device 100 using the etching chamber may be maintained in a pressurized atmosphere when the object W is etched, and at this time, the pressurized atmosphere may be maintained at a pressure of 0.1 bar to 10 bar.
By maintaining the inside of the etching device 100 using the etching chamber as described above in a pressurized atmosphere, it is possible to prevent vaporization (to prevent vaporization of moisture and/or additives included in the etchant) of the etchant L. Accordingly, a concentration of etchant L may be kept constant, and thus, an etching selectivity of the object W may be remarkably improved. In this case, the etching selectivity may be expressed as a ratio of an etching rate of a film for etching with respect to an etching rate of an unetched film among films formed on the object W, and for example, in the case of a silicon nitride film etching process which is one of main manufacturing processes of a semiconductor chip, the etching selectivity may be expressed as a ratio of an etching rate of a silicon nitride film with respect to an etching rate of a silicon oxide film.
In general, when etching the silicon nitride film, phosphoric acid and a phosphoric acid composition imparting characteristics to phosphoric acid are mainly used. The phosphoric acid or phosphoric acid composition has characteristics that the silicon nitride film is well etched under certain conditions, but the etching rate of the silicon oxide film formed on a side surface and a lower portion of the silicon nitride film is remarkably low.
As the main factor indicating the etching selectivity, in general phosphoric acid, moisture contained together with phosphoric acid, which is the main component, may be exemplary. In the phosphoric acid composition, in addition to the phosphoric acid and moisture which are the main components, Si-based or Si-containing additives, which are major additive components, low-molecular-weight glycol-based silicon oxide etching inhibitors, ammonium salt-based hydrous silica solvents, or the like may be exemplary.
However, except for pure phosphoric acid and Si-based additives which are inorganic components, moisture, low-molecular weight silicon oxide film etching inhibitors, hydrous silica solvents, or the like are easily vaporized under high temperature conditions. For this reason, there is a problem in that properties of the etchant are changed due to vaporization of the components contained in the composition during an etching process for a long time (one minute or more) under high temperature (100° C. or higher) conditions. In order to solve the problem, a device for removing the silicon nitride film is designed to constantly replenish moisture vaporized in a storage tank or an in-line heating device for heating a solution or a chamber where the etching is performed or is designed to constantly replenish a new liquid.
For this reason, when storage or etching processing conditions of the etchant are not well managed, a defect rate of a product increases, and when an amount of use increases to avoid this, consumption of the etchant increases, and there may be a problem that a product cost increases.
Meanwhile, when the storage tank which heats (preheats) the etchant in a high-temperature etching process or the etching chamber 400 where the actual etching occurs is pressurized, the concentration of the etchant L is kept constant due to the pressurization. Accordingly, since characteristics of the etchant L are not changed, the defect rate of the process can be lowered. Moreover, in order to maintain the concentration, it is not necessary to add deionized water and the etchant separately added in the related art, and thus, cost can be greatly reduced in terms of economy.
In one embodiment of the present invention, when the pressurized atmosphere is maintained at a pressure of less than 0.1 bar, the pressure is too low, it is not possible to prevent the vaporization of the etchant L described above. Moreover, when the pressured atmosphere is maintained at a pressure of more than 10 bar, the pressure is too high, and it is difficult to configure the device. Accordingly, the etching characteristics can be changed easily due to a small pressure difference, which is not desirable in terms of economic efficiency.
In one embodiment of the present invention, the etching device 100 using an etching chamber may further include a temperature control unit 600 which controls the temperature of the etchant L in the etchant storage chamber 300.
The temperature control unit 600 may be a heating unit for heating the etchant L or a cooling unit for cooling the etchant L, is not limited as long as it is a device capable of controlling the temperature of the etchant L inside the etchant storage chamber 300, and may be a device for maintaining an appropriate temperature according to a type of etchant L. In addition, the temperature control unit 600 may also control a temperature inside the etching chamber 400, and in this case, one temperature control unit 600 may control the temperatures of both the etchant storage chamber 300 and the etching chamber 400, or the temperature control unit 600 may be separately installed in each of the chambers 300 and 400. That is, in the etching device 100 using an etching chamber, by heating or cooling the temperature of the etchant L inside the etchant storage chamber 300 in advance, the etchant L may be sprayed immediately to the etching chamber 400, and thus, it is possible to reduce a process time and perform serial processes.
In one embodiment of the present invention, when the etchant L is a silicon nitride film etchant containing phosphoric acid, a temperature thereof may be controlled at 150° C. to 250° C. and preferably 150° C. to 210° C. When the temperature is outside the above range and is controlled to be less than 150° C., the etching rates of the silicon nitride film and the silicon oxide film are low, and it is difficult to check effects. Moreover, when the temperature is controlled above 250° C. (preferably 210° C.), the etching rates of the silicon nitride film and the silicon oxide film are extremely high, a vapor pressure of the vaporized moisture is high, and thus, it can be difficult to check the effects. However, although the silicon nitride film etchant is exemplified above, it is not limited thereto, and when other etchants are used, it may be controlled to a suitable temperature. The etchant L according to one embodiment of the present invention may selectively use at least one or a mixture of one or more of HF, NHO3, H2O2, IPA, NH4OH, H2O, H3PO4, and H2SO4.
In one embodiment of the present invention, the etching device 100 using an etching chamber may further include a discharge unit (not illustrated) for discharging the etchant L in a lower portion of the etching chamber 400. The discharge unit is for discharging the etchant L in the etching chamber 400 to the outside after the etching is completed and is not limited as long as the etchant L is discharged to the outside. However, preferably, the etchant L may be discharged through a pipe.
In addition, the discharge unit may be also installed in a lower portion of the etchant storage chamber 300, and the discharge unit may be for discharging the etchant L remaining in the etchant storage chamber 300 after the etching is completed.
In one embodiment of the present invention, the etching device 100 using an etching chamber may further include a cleaning liquid storage chamber (not illustrated) for storing a cleaning liquid for cleaning the inside of the etching chamber 400, and the cleaning liquids storage chamber may be connected to the etching chamber 400.
The cleaning liquid storage chamber is for storing the cleaning liquid for cleaning the inside of the etching chamber 400 after the etching is completed. Preferably, the etchant L in the etching chamber 400 may be discharged to the outside when the etching is completed, and thereafter, the cleaning liquid may be introduced into the etching chamber 400 to perform cleaning. In this case, the cleaning liquid is not limited as long as it is a material for cleaning the etchant L remaining in the etching chamber 400, and for example, deionized water may be used as the cleaning liquid.
Meanwhile, the cleaning liquid may clean the inside of the etchant storage chamber 300, and in this case, the cleaning liquid storage chamber may be connected to the etchant storage chamber 300.
The etching device using an etching chamber according to one embodiment of the present invention will be described with reference to
The etching chamber 900 may be provided to be openable and closeable and communicates with the etchant storage chamber 300 through the connection unit 500, the etchant L is supplied to an internal pressure chamber 901 in a closed state during the etching process, and the pressure chamber 901 is maintained in a pressurized atmosphere by the pressurization unit 700.
The etching chamber 900 may include a first chamber 910, in which the pressure chamber 901 is formed, and a second chamber 920 provided to be openable and closeable above the first chamber 910. The pressure chamber 901 of the first chamber 910 may be open upward, and a first fastening portion 911 to which a rotating shaft 953 described below is coupled and a second fastening portion 912 to which a raising/lowering pin 963 described below is coupled may be formed to vertically pass through a lower portion of the first chamber 910. The second chamber 920 may be coupled to and separated from an upper portion of the first chamber 910 to open and close the pressure chamber 901, and when the second chamber 920 is coupled to the first chamber 910, an etchant inlet 921 is formed so that the etchant L is supplied into the pressure chamber 901. The etchant storage chamber 300 may be connected to the etchant inlet 921 by the connection unit 500.
In addition, the second chamber 920 may have a cleaning water inlet 922 formed to supply cleaning water from the outside, the cleaning water inlet 922 may be connected to the cleaning water supply unit 162 by the supply line 161, and the pressurization unit 700 for pressurizing the inside of the pressure chamber 901 and the exhaust unit 800 for discharging the internal pressure of the pressure chamber 901 to the outside may be connected to the etching chamber 900.
The cup portion 940 may be disposed inside the pressure chamber 901, an accommodation portion 941 for accommodating the etchant L and the cleaning water may be formed to be recessed in an upper portion of the cup portion 940, and a discharge unit 942 for discharging the etchant L to the outside of the first chamber 910 may be formed in the cup portion 940.
One or more supports 943 may protrude from a bottom of the cup portion 940, the support 943 may be placed on a bottom surface of the pressure chamber 901 to support the cup portion 940 at a predetermined height, and in this case, the cup portion 940 may be spaced apart and upward from the bottom surface of the pressure chamber 901.
Meanwhile, unlike the method of fixing the object W using the chuck after placing the object W on the support pin of the mounting table 410, in the mounting table 950 according to another embodiment of the present invention, a method of placing the object W by forming an etching performance improvement unit in the mounting table 950 may be used.
The mounting table 950 according to one embodiment of the present invention may be rotatably disposed inside or above the cup portion 940 with respect to a vertical rotation center. The etching performance improvement unit on which the etching object W is placed is formed on an upper portion of the mounting table 950. The mounting table 950 may have a disk shape, the rotating shaft 953 forming the vertical rotation center may protrude vertically from the lower portion of the mounting table 950, and the rotating shaft 953 may vertically pass through the first fastening portion 911 of the first chamber 910 to be coupled thereto.
A rotation driving unit 955 may be mechanically connected to the rotating shaft 953, and the mounting table 950 may be rotated by a rotational force transmitted from the rotation driving unit 955 to the rotating shaft 953.
A ring-shaped first sealing member that surrounds the rotating shaft 953 in a rotation direction in a state of being pressed against the rotating shaft 953 may be further provided in the first fastening portion 911, and the first sealing member may be formed of a material such as Teflon (polytetrafluoroethylene (PTFE)).
The first lip portion may protrude from an inner peripheral surface of the first sealing member, and first lip portions may be consecutively formed along the inner peripheral surface of the first sealing member. The first lip portion may protrude obliquely upward or downward to be pressed against the rotating shaft 953 obliquely in a radial direction (rotation direction), and one or more of the first lip portions may be arranged in a vertical direction of the first sealing member.
In the first sealing member, the first lip portion is pressed against an outer surface of the rotating shaft 953, and thus, airtight performance between the first fastening portion 911 and the rotating shaft 953 may be secured.
In addition, a bearing that rotatably supports the rotating shaft 953 in the radial direction of the rotating shaft 953 may be coupled to the first fastening portion 911, the bearing may be located above and below the first sealing member, and a washer member surrounding the rotating shaft 953 in the radial direction of the rotating shaft 953 may be coupled between the bearing and the first sealing member.
The etching performance improvement unit according to one embodiment of the present invention is formed to be recessed so that the object W is placed in a state of being inserted and immersed in the etchant L, and the etching performance improvement unit may include a seating surface 951 that is formed along an edge of the etching performance improvement unit so that the object W is placed thereon and a stepped portion 952 that is formed along the edge of the seating surface 951 to accommodate the etchant L1 above the object W.
The seating surface 951 may be continuously formed along an inner peripheral surface of the mounting table 950, an upper end of the stepped portion 952 may be located higher than the seating surface 951, and the stepped portion 952 may be continuously formed along the edge of the seating surface 951.
In addition, a passage 954 through which air passes upward or downward may vertically pass through the mounting table 950, and thus, the passage 954 allows the air to pass upward and downward. Therefore, when the edge of the object W is placed on the seating surface 951, it is possible to prevent the object W from being raised due to buoyancy.
The raising/lowering unit 960 is for raising or lowering the object W inside the pressure chamber 901. When the raising/lowering unit 960 is raised, the object W is located above the mounting table 950, and when the raising/lowering unit 960 is lowered, the object W is placed on the etching performance improvement unit. The raising/lowering unit 960 is a body 961 that may be raised or lowered from a lower portion of the cup portion 940 and a support pin 962 that protrudes upward from the body 961 to be raised or lowered through the passage 954 and supports the lower portion of the object W.
The raising/lowering pin 963 may vertically protrude from the lower portion of the body 961, the raising/lowering pin 963 may vertically pass through the second fastening portion 912 of the first chamber 910 to be coupled thereto, and a raising/lowering driver 964 may be mechanically connected to the raising/lowering pin 963.
A ring-shaped second sealing member (not illustrated) that surrounds the raising/lowering pin 963 in a state of being pressed against the raising/lowering pin 963 in a width direction may be further provided in the second fastening portion 912, and the second sealing member may be formed of a material such as Teflon (polytetrafluoroethylene (PTFE)).
A second lip portion may protrude from an inner peripheral surface of the second sealing member, and second lip portions may be consecutively formed along the inner peripheral surface of the second sealing member. The second lip portion may protrude obliquely upward or downward to be pressed against the raising/lowering pin 963 obliquely in the width direction of the raising/lowering pin 963, and one or more of the second lip portions may be arranged in the vertical direction of the second sealing member.
In the second sealing member, since the second lip portion is pressed against an outer surface of the raising/lowering pin 963, airtight performance between the second fastening portion 912 and the raising/lowering pin 963 may be secured.
In addition, a ring-shaped first O-ring member may be coupled between the outer peripheral surface of the first sealing member and the first fastening portion 911, and a ring-shaped second O-ring member may be coupled between the outer peripheral surface of the second sealing member and the second fastening portion 912.
The first O-ring member and the second O-ring member may be manufactured using a material such as rubber, and an installation portion is recessed so that the inner peripheral surfaces of the first O-ring member and the second O-ring member are inserted into the outer peripheral surfaces of the first sealing member and the second sealing members.
Meanwhile, a bearing that rotatably supports the raising/lowering pin 963 in the width direction of the raising/lowering pin 963 may be coupled to the second fastening portion 912, the bearing may be located above and below the second sealing member, and a washer member (not illustrated) surrounding the raising/lowering pin 963 in the width direction of the raising/lowering pin 963 may be coupled between the bearing and the second sealing member.
In one embodiment of the present invention, the etchant L may be a silicon nitride film etchant, and the silicon nitride film etchant may include phosphoric acid and water. In this case, a composition of the silicon nitride film etchant may be mixed in an amount of 10 parts by weight to 20 parts by weight of water relative to 100 parts by weight of phosphoric acid, preferably 15 parts by weight to 20 parts by weight, and most preferably, 85 wt % of phosphoric acid and 15 wt % of water.
Hereinafter, examples of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the examples described herein.
(1) Preparation of Silylphosphine Oxide-Based Additive Compound
A silylphosphine oxide-based compound according to one aspect of the present invention was prepared.
First, H3PO4 anhydride (100%, 300 g) and Tetra-Ethyl-Ortho-Silicate (TEOS, 99%, 30 g) were mixed, and then, stirred at 60 rpm for 10 minutes to be mixed.
Next, the mixture was first reacted while being stirred at 60 rpm for 8 hours at a temperature of 60° C.
Next, after the first reaction was completed, a temperature of a reactor was raised to 120° C., the mixture was stirred at 60 rpm for 12 hours, and the secondary reaction was carried out.
Next, after the secondary reaction was completed, the temperature of the reactor was raised to 260° C., the mixture was stirred at 60 rpm for 3 hours, and a tertiary reaction was carried out.
Finally, after the tertiary reaction was completed, the temperature of the reactor was cooled to room temperature to obtain a silylphosphine oxide-based compound.
(2) Preparation of Silicon Nitride Film Etchant Composition Containing Silylphosphine Oxide-Based Compound
The silylphosphine oxide-based compound (SiP, 0.1 wt %) prepared in (1), phosphoric acid (H3PO4, 85 wt %), water (H2O, 14.8 wt %), and an inhibitor (0.1 wt %) were mixed at 60 rpm for three hours at room temperature, and a phosphoric acid etchant composition including a silylphosphine oxide-based compound as an additive was prepared.
Preparation of Composition
Without mixing the (1) silylphosphine oxide-based compound of Preparation Example 1, only phosphoric acid (H3PO4, 85 wt %) and water (H2O, 15.0 wt %) were mixed to prepare the phosphoric acid etchant composition.
(1) Preparation of Silyl Phosphate-Based Additive Compound
A silyl phosphate-based compound according to one aspect of the present invention was prepared.
First, H3PO4 anhydride (100%, 300 g) and Tetra-Ethyl-Ortho-Silicate (TEOS, 99%, 30 g) were mixed, and then, stirred at 60 rpm for 10 minutes to be mixed.
Next, the mixture was first reacted while being stirred at 60 rpm for 8 hours at a temperature of 80° C.
Next, after the first reaction was completed, the temperature of the reactor was raised to 120° C., and the mixture was stirred at 60 rpm for 12 hours, and the secondary reaction was carried out.
Finally, after the secondary reaction was completed, the temperature of the reactor was cooled to room temperature to obtain a silyl phosphate-based compound.
(2) Preparation of Silicon Nitride Film Etchant Composition Containing Silyl Phosphate-Based Compound
The silyl phosphate-based compound (SiOP, 0.05 wt %) prepared in (1), phosphoric acid (H3PO4, 85 wt %), water (H2O, 14.85 wt %), and inhibitor (0.1 wt %) were mixed at 60 rpm for three hours at room temperature, and a phosphoric acid etchant composition including a silyl phosphate-based compound as an additive was prepared.
In order to evaluate the performance of the etching device 100 using the single wafer type etching chamber according to the present invention, the etchant composition prepared in Preparation Examples 1 to 3 was used as an etchant, and a wafer on which a silicon nitride film of 250 nm was formed was etched while conditions were changed as illustrated in Table 1 below. In this case, the wafer etching was performed for 3 minutes each, and the rotation speed was 150 rpm.
When the wafer etching was performed under conditions of Examples 1 to 13 and Comparative Examples 1 to 5, an etching rate of the silicon nitride film and an etching rate of the silicon oxide film were measured, and an etching selectivity (etching rate of silicon nitride film/etching rate of silicon oxide film) of the silicon nitride film with respect to the silicon oxide film was calculated and illustrated in Table 2 below.
As illustrated in Table 2, in cases of Examples 1 to 13 in which etching was performed under pressurized conditions using the etching device using the single wafer type etching chamber of the present invention, compared to Comparative Examples 1 to 5 in which the etching was performed at 0 bar, when the conditions other than pressure were the same, it was confirmed that the selectivity of the silicon nitride film to the silicon oxide film was superior.
In order to evaluate the performance of the etching device using the batch type etching chamber according to the present invention, the etchant composition prepared in Preparation Examples 1 to 4 was used as an etchant, and a wafer on which a silicon nitride film of 250 nm was formed was etched while conditions were changed as illustrated in Table 3 below. In this case, the wafer etching was performed for 20 minutes each.
When wafer etching was performed under conditions of Examples 1 to 12 and Comparative Examples 1 to 7, the etching rate of the silicon nitride film and the etching rate of the silicon oxide film were measured, and the etching selectivity (etching rate of silicon nitride film/etching rate of silicon oxide film) of the silicon nitride film with respect to the silicon oxide film was calculated and illustrated in Table 4 below.
As illustrated in Table 4, in cases of Examples 1 to 12 in which etching was performed under pressurized conditions using the etching device using the batch type etching chamber of the present invention, compared to Comparative Examples 1 to 7 in which the etching was performed at 0 bar, when the conditions other than pressure were the same, it was confirmed that the selectivity of the silicon nitride film to the silicon oxide film was superior.
In the etching device using an etching chamber according to the embodiments of the present invention, it is possible to prevent the vaporization of the etchant L by pressurizing the etchant storage chambers 110 and 300 and/or the etching chambers 130 and 400. Therefore, the concentration of the etchant L is kept constant, and thus, the etching selectivity can be remarkably improved.
In addition, since the concentration of the etchant L is kept constant due to the pressurization, additional deionized water and an additional input of the etchant are not required to maintain the concentration of the etchant. Accordingly, it is possible to improve a product yield and reduce consumption of the etchant L, and in economic terms, cost can be greatly reduced.
The present invention is described with reference to the embodiments illustrated in the drawings, but these are only exemplary, and those of ordinary skill in the art will appreciate that various modifications and equivalent other embodiments are possible therefrom. Therefore, a true technical protection scope of the present invention should be determined by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2019-0047050 | Apr 2019 | KR | national |
This application is a national entry of International Application No. PCT/KR2020/005304, filed on Apr. 22, 2020, which claims under 35 U.S.C. § 119(a) and 365(b) priority to and benefits of Korean Patent Application No. 10-2019-0047050, filed on Apr. 23, 2019 in the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2020/005304 | 4/22/2020 | WO | 00 |
