Multi-wafer etching device

Abstract

The present application discloses a multi-wafer etching device, which includes an etching chamber, a wafer holder, a first intake air regulating mechanism, a second intake air regulating mechanism, a first exhaust air regulating mechanism, and a second exhaust air regulating mechanism. An intake air port and an exhaust air port are provided on the etching chamber. The first intake air regulating mechanism, the second intake air regulating mechanism, the first exhaust air regulating mechanism, and the second exhaust air regulating mechanism all include a regulating plate and a regulator. The regulator can change the spacing of the regulating plates. By adjusting the gap between the regulating plates at the intake air end and / or the exhaust air end, the gas flow path can be changed, so as to balance the etching rates of the upper and lower wafers.

Description

Technical Field

[0001] The present application relates to the field of wafer etching technology, and in particular to a multi-wafer etching device. Background Art

[0002] In the semiconductor manufacturing industry, wafer etching is a key process that plays a decisive role in the performance and quality of chips. With the continuous development of semiconductor technology, in order to improve production efficiency and reduce production costs, multi-wafer etching processes are increasingly being adopted.

[0003] In the multi-wafer etching process, specific process vapors are usually used. These vapors contain active components that can react with the surface materials of the wafers to achieve etching of the wafers. However, the current multi-wafer etching process faces a more difficult problem - as the etching continues, the process vapors themselves have a certain weight, and under the action of gravity, these vapors will gradually settle downwards.

[0004] Since multiple wafers are stacked vertically in the etching equipment, the process vapor deposits downward, causing the vapor concentration around the lower wafer to be significantly higher than that of the upper wafer. Since the etching rate depends largely on the process vapor concentration around the wafer, the etching speed of the lower wafer is significantly faster than that of the upper wafer.

[0005] This difference in etching speed will lead to inconsistent etching depths between wafers, making it difficult to ensure wafer processing accuracy, which in turn affects chip performance and yield. Summary of the invention

[0006] The purpose of the present application is to overcome the deficiencies in the prior art and provide a multi-wafer etching device.

[0007] The present application provides a multi-wafer etching device, comprising: an etching chamber for providing a space for wafer etching, with an air inlet provided on one side of the etching chamber and an air outlet provided on the other side opposite thereto; a wafer holder disposed in the etching chamber for supporting wafers, the wafer holder being a multi-layer support structure capable of simultaneously carrying multiple wafers and enabling the wafers to be spaced apart in the vertical direction; a first air inlet adjustment mechanism disposed in the etching chamber and on the side of the first air distribution plate away from the air inlet, the first air inlet adjustment mechanism including a plurality of first adjustment plates and a first adjuster, the plurality of first adjustment plates being spaced apart in the vertical direction, and the first adjuster being used to adjust the gap between the first adjustment plates; a second air inlet adjustment mechanism also disposed in the etching chamber and on the side of the first air distribution plate away from the air inlet, the second air inlet adjustment mechanism including a plurality of second adjustment plates and a second adjuster, the plurality of second adjustment plates being spaced apart in the vertical direction, and the second adjuster being used to adjust the gap between the second adjustment plates, the first adjustment plates and the second adjustment plates being arranged side by side in the vertical direction; a first air outlet adjustment mechanism disposed in the etching chamber and near the air outlet, the first air outlet adjustment mechanism including a plurality of third adjustment plates and a third adjuster, the plurality of third adjustment plates being spaced apart in the vertical direction, and the third adjuster being used to adjust the gap between the third adjustment plates, the first adjustment plates and the third adjustment plates being disposed opposite to each other in the horizontal direction, and the wafer holder being located between the first adjustment plates and the third adjustment plates; a second air outlet adjustment mechanism also disposed in the etching chamber and near the air outlet, the second air outlet adjustment mechanism including a plurality of fourth adjustment plates and a fourth adjuster, the plurality of fourth adjustment plates being spaced apart in the vertical direction, and the fourth adjuster being used to adjust the gap between the fourth adjustment plates, the second adjustment plates and the fourth adjustment plates being disposed opposite to each other in the horizontal direction, and the wafer holder being located between the second adjustment plates and the fourth adjustment plates, the third adjustment plates and the fourth adjustment plates being arranged side by side in the vertical direction; during the etching process, the process steam enters the first air cavity through the air inlet, and the first air cavity helps the process steam to diffuse and uniformly flow out from the first air holes; the flowing process steam acts on the wafers on the wafer holder through the gap between the first adjustment plates and the second adjustment plates, thereby realizing the etching of the wafers; the process steam that does not participate in the reaction and the by-products generated by the etching can be discharged through the air outlet after passing through the gap between the third adjustment plates and the fourth adjustment plates; as the etching progresses, under the influence of gravity, the process steam will naturally deposit downward, resulting in a higher etching rate of the wafers in the lower layer than that of the wafers in the upper layer; the first air inlet adjustment mechanism is disposed above the second air inlet adjustment mechanism; by increasing the gap between the first adjustment plates through the first adjuster and decreasing the gap between the second adjustment plates through the second adjuster, the process steam will preferentially flow through the first air outlet adjustment mechanism, thereby increasing the process steam flow rate in the upper layer and promoting the etching of the wafers in the upper layer;By increasing the gap between the third adjustment plates through the third regulator and reducing the gap between the fourth adjustment plates through the fourth regulator, the process steam will preferentially flow through the first outlet adjustment mechanism, thereby preventing the process steam from depositing downward, thereby optimizing the etching effect of the upper and lower wafers. ;

[0008] Further, the first regulator, the second regulator, the third regulator and / or the fourth regulator include: an adjusting shaft, which is rotatably arranged in the etching chamber and extends in the vertical direction, and a plurality of groups of symmetrically distributed guide grooves are provided on the adjusting shaft, and a group of guide grooves serving as the symmetry axis extends horizontally along the circumference of the adjusting shaft, and the other guide grooves extend obliquely compared to the symmetry axis, and the inclination angle gradually increases from both sides of the symmetry axis to form a continuous gradient layout; an adjusting driving member, used to drive the adjusting shaft to rotate; a plurality of adjusting sliders, an adjusting slider being slidably arranged in any guide groove, and any adjusting slider being connected to an adjusting plate; when it is necessary to change the distribution of the inlet or outlet airflow, the adjusting shaft is driven to rotate by the adjusting driving member, and the adjusting slider can slide along the guide groove, and affected by the layout of the guide groove, a set of adjusting plates connected to the adjusting slider can move in the vertical direction and change the spacing.

[0009] Furthermore, the multi-wafer etching device also includes: a first gas uniformizing plate, which is arranged in the etching chamber and adjacent to the air inlet, and a plurality of first air holes are opened on the first gas uniformizing plate, and the plurality of first air holes are evenly spaced along the vertical direction, and a first air cavity is formed between the first gas uniformizing plate and the air inlet, and the first air inlet regulating mechanism and the second air inlet regulating mechanism are located on the side of the first gas uniformizing plate away from the air inlet; a second gas uniformizing plate, which is arranged in the etching chamber and adjacent to the air outlet, and a plurality of second air holes are opened on the second gas uniformizing plate, and the plurality of second air holes are evenly spaced along the vertical direction, and a second air cavity is formed between the second gas uniformizing plate and the air outlet; the process steam that does not participate in the reaction and the by-products generated by etching will enter the second air cavity through the second air holes during the discharge process, and the second air cavity can buffer the fluctuation of the pumping speed, balance the pressure change, and play a role in maintaining the stability of the air pressure in the etching chamber.

[0010] Furthermore, the multi-wafer etching device also includes a temperature control mechanism, which is used to heat the etching chamber to maintain 60°C in the etching chamber; the temperature control mechanism includes a heating belt, and heating belts are attached to each outer wall of the etching chamber to fully heat the etching chamber and ensure that the temperature in the etching chamber is uniform everywhere.

[0011] Furthermore, the air inlet is connected to the process steam supply equipment through the air inlet pipe, and the air outlet is connected to the vacuum equipment through the air outlet pipe, and the air inlet pipe and / or the air outlet pipe are also affixed with a heating belt; and / or, the temperature control mechanism also includes a heating wire, the etching chamber includes an outer jacket and an inner liner, the outer jacket is made of metal material, and the inner liner is made of high temperature resistant and corrosion resistant material, and the heating wire is embedded between the outer jacket and the inner liner.

[0012] Furthermore, a lifting cavity is provided below the etching cavity. A lifting platform is arranged in the lifting cavity, and the wafer is placed on the lifting platform. After etching a batch of wafers, the lifting platform descends with the wafer holder, so that the wafer holder enters the lifting cavity. A wafer inlet / outlet is provided on the lifting cavity. Through the wafer inlet / outlet, the unloading of the etched wafers and the loading of the wafers to be etched can be realized. After the wafer holder holds the wafers to be etched, the lifting platform ascends with the wafer holder, so that the wafer holder enters the etching cavity for the wafers to be etched.

[0013] Furthermore, the wafer holder is detachably arranged on the lifting platform; the wafer holder loaded with the etched wafers is unloaded to achieve rapid unloading; the wafer holder loaded with the wafers to be etched is loaded to achieve rapid loading.

[0014] Furthermore, the lifting platform includes: a platform part for installing the wafer holder and capable of making a lifting movement under the drive of a lifting driver; a cover part arranged directly above the platform part; a connecting rod for connecting the platform part and the cover part; when the wafer holder is placed on the lifting platform, the wafer holder is located between the platform part and the cover part; the multi-wafer etching device further includes an auxiliary air supply pipeline arranged in the lifting platform and communicating with a process steam supply device; a first air outlet hole is provided on the bottom surface of the cover part facing the platform part, and the first air outlet hole communicates with the auxiliary air supply pipeline, and / or, a second air outlet hole is provided on the side surface of the connecting rod facing the wafer holder, and the second air outlet hole communicates with the auxiliary air supply pipeline; during the etching process, the process steam can be sprayed onto the wafers through the first air outlet hole and / or the second air outlet hole.

[0015] Furthermore, a communication channel is provided between the etching cavity and the lifting cavity. The lifting platform and the wafer holder can move between the etching cavity and the lifting cavity through the communication channel; after the lifting platform enters the etching cavity with the wafer holder, the platform part can seal the communication channel to prevent the process steam from entering the lifting cavity; after the lifting platform enters the lifting cavity with the wafer holder, the cover part can seal the communication channel to avoid interference between the processing operations in the lifting cavity and the etching cavity.

[0016] Furthermore, a cover is provided at the top of the wafer holder. Auxiliary air holes are provided on the side of the cover facing the wafers, and the auxiliary air holes communicate with the process steam supply device; the total etching time is 2N. After the etching time exceeds N, at the air inlet end, the gap between the first adjusting plates is increased and the gap between the second adjusting plates is decreased, and at the air outlet end, the gap between the third adjusting plates is increased and the gap between the fourth adjusting plates is decreased. At the same time, the auxiliary air holes are enabled, so that the process steam is sprayed onto the wafers from top to bottom, which can effectively improve the etching difference between the upper and lower wafers.

[0017] The present application provides a multi-wafer etching device, including an etching chamber, a wafer holder, a first intake air regulating mechanism, a second intake air regulating mechanism, a first exhaust air regulating mechanism, and a second exhaust air regulating mechanism. An intake port and an exhaust port are provided on the etching chamber. The first intake air regulating mechanism, the second intake air regulating mechanism, the first exhaust air regulating mechanism, and the second exhaust air regulating mechanism all include a regulating plate and a regulator. The regulator can change the distance between the regulating plates. By adjusting the gap between the regulating plates at the intake end and / or the exhaust end, the gas flow path can be changed, thereby balancing the etching rates of the upper and lower wafers. Description of the Drawings

[0018] Figure 1 It is a schematic structural diagram of a multi-wafer etching device provided by the present application;

[0019] Figure 2 For Figure 1 the enlarged structural diagram of the structure within the circle A in

[0020] Figure 3 For Figure 1 the enlarged structural diagram of the structure within the circle B in

[0021] Figure 4 For Figure 1 the schematic structural diagram of the first air distribution plate, the first intake air regulating mechanism, and the second intake air regulating mechanism in the multi-wafer etching device shown;

[0022] Figure 5 For Figure 4 the structural cross-sectional view after omitting the adjustment driving member;

[0023] Figure 6 For Figure 4 the schematic structural diagram of the adjustment rotating shaft in

[0024] Figure 7 It is a schematic structural diagram of another multi-wafer etching device provided by the present application. Detailed Description of the Embodiments

[0025] To make the above objects, features, and advantages of the present application more obvious and understandable, the following will describe the detailed embodiments of the present application in conjunction with the accompanying drawings. Many specific details are set forth in the following description to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein. Those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0026] The present application provides a multi-wafer etching device, including: an etching chamber 100 for providing space for wafer etching, with an air inlet 101 provided on one side of the etching chamber 100 and an air outlet 102 provided on the opposite side; a wafer holder 200 disposed in the etching chamber 100 for supporting wafers. The wafer holder 200 is a multi-layer support structure capable of simultaneously carrying multiple wafers and arranging these wafers at intervals in the vertical direction; a first air distribution plate 310 disposed in the etching chamber 100 and adjacent to the air inlet 101. The first air distribution plate 310 is provided with a plurality of first air holes, and the plurality of first air holes are equally spaced in the vertical direction. A first air cavity 103 is formed between the first air distribution plate 310 and the air inlet 101.

[0027] In a specific embodiment, the process steam is VHF (hydrogen fluoride vapor), supplemented with gaseous ethanol (EtOH) and nitrogen (N2). The process steam can enter the etching chamber 100 through the air inlet 101. After contacting the wafer, the process steam will chemically react with the silicon dioxide (SiO2) on the wafer surface to generate volatile products.

[0028] Specifically, the chemical reaction formula is: SiO2 + 4HF → SiF4↑ + 2H2O↑. Among them, gaseous SiF4 (silicon tetrafluoride) and H2O (water vapor) can be removed by a vacuum device through the air outlet 102, thereby achieving precise removal of silicon dioxide.

[0029] Among them, ethanol acts as a passivating agent, which can inhibit lateral etching, making the etching mainly proceed in the direction perpendicular to the wafer surface, and can also improve the anisotropy of etching, helping to form an accurate etching pattern. In addition, gaseous ethanol can also combine with water to form an azeotrope, which can reduce the residual water vapor and avoid interfering with the process, thereby ensuring the stability and accuracy of etching.

[0030] Nitrogen acts as a carrier gas to dilute the concentration of hydrogen fluoride. By adjusting the ratio of nitrogen to hydrogen fluoride, the reaction rate can be effectively controlled to avoid over-etching or uneven etching caused by too intense a reaction. When vaporizing ethanol, nitrogen can also lower the boiling point of ethanol by pressurization, facilitating the vaporization of ethanol. At the same time, nitrogen pressurization also helps to prevent the liquefaction of gaseous ethanol to ensure that ethanol remains gaseous during the etching process, thereby maintaining the gaseous stability of the process steam.

[0031] Specifically, reference can be made to Figure 1 , in the illustrated embodiment, the air inlet 101 is provided on the right side of the etching chamber 100, and the air inlet 101 is connected to a process steam supply device through an air inlet pipe. The air outlet 102 is provided on the left side of the etching chamber 100, and the air outlet 102 is connected to a vacuum device through an air outlet pipe.

[0032] Continue to refer to Figure 1, the wafer holder 200 is installed inside the etching chamber 100. The wafer holder 200 includes at least two vertical rods, and a plurality of support blocks are arranged on any one of the vertical rods. The plurality of support blocks on the same vertical rod are equally spaced in the vertical direction, and the support blocks on different vertical rods and in the same plane can cooperate to support a wafer. With such an arrangement, the shielding area of the wafer holder 200 for the wafer is small, so that the wafer can fully contact the process steam.

[0033] On the wafer holder 200, multiple wafers are stacked vertically, and there is a gap between the wafers. Each wafer can fully contact the process steam, and the wafers do not interfere with each other, so as to meet the requirement of etching multiple wafers simultaneously.

[0034] With reference to Figure 2 , the first gas distribution plate 310 is arranged in the etching chamber 100 and on the left side of the gas inlet 101. There is a gap between the first gas distribution plate 310 and the right chamber wall where the gas inlet 101 is located, and the gap forms a sealed first gas chamber 103. A plurality of first air holes are arranged on the first gas distribution plate 310 at equal intervals in the vertical direction, and the first air holes communicate the first gas chamber 103 and the etching chamber 100.

[0035] The process steam introduced through the gas inlet 101 will first enter the first gas chamber 103. After diffusing in the first gas chamber 103, the process steam can evenly flow into each of the first air holes and flow uniformly to the etching area (i.e., the position where the wafer holder 200 is located) through these first air holes. The existence of the first gas chamber 103 can make the process steam achieve uniform distribution before entering the etching area, thus ensuring the uniformity of etching.

[0036] The multi-wafer etching device provided by this application further includes: a first intake air regulating mechanism 410, which is disposed in the etching chamber 100 and on the side of the first air distribution plate 310 away from the air inlet 101. The first intake air regulating mechanism 410 includes a plurality of first regulating plates 411 and a first regulator 412. The plurality of first regulating plates 411 are arranged at intervals in the vertical direction, and the first regulator 412 is used to adjust the gap between the first regulating plates 411; a second intake air regulating mechanism 420, which is also disposed in the etching chamber 100 and on the side of the first air distribution plate 310 away from the air inlet 101. The second intake air regulating mechanism 420 includes a plurality of second regulating plates 421 and a second regulator 422. The plurality of second regulating plates 421 are arranged at intervals in the vertical direction, and the second regulator 422 is used to adjust the gap between the second regulating plates 421. The first regulating plates 411 and the second regulating plates 421 are arranged side by side in the vertical direction; a first exhaust air regulating mechanism 430, which is disposed in the etching chamber 100 and near the air outlet 102. The first exhaust air regulating mechanism 430 includes a plurality of third regulating plates 431 and a third regulator 432. The plurality of third regulating plates 431 are arranged at intervals in the vertical direction, and the third regulator 432 is used to adjust the gap between the third regulating plates 431. The first regulating plates 411 and the third regulating plates 431 are arranged opposite to each other in the horizontal direction, and the wafer holder 200 is located between the first regulating plates 411 and the third regulating plates 431; a second exhaust air regulating mechanism 440, which is also disposed in the etching chamber 100 and near the air outlet 102. The second exhaust air regulating mechanism 440 includes a plurality of fourth regulating plates 441 and a fourth regulator 442. The plurality of fourth regulating plates 441 are arranged at intervals in the vertical direction, and the fourth regulator 442 is used to adjust the gap between the fourth regulating plates 441. The second regulating plates 421 and the fourth regulating plates 441 are arranged opposite to each other in the horizontal direction, and the wafer holder 200 is located between the second regulating plates 421 and the fourth regulating plates 441. The third regulating plates 431 and the fourth regulating plates 441 are arranged side by side in the vertical direction.

[0037] During the etching process, the process steam enters the first air cavity 103 through the air inlet 101. The first air cavity 103 helps the process steam to diffuse and uniformly flow out from the first air holes; the flowing process steam acts on the wafers on the wafer holder 200 through the gap between the first regulating plates 411 and the second regulating plates 421, so as to realize the etching of the wafers; the process steam that does not participate in the reaction and the by-products generated by the etching can be discharged through the air outlet 102 after passing through the gap between the third regulating plates 431 and the fourth regulating plates 441.

[0038] As the etching progresses, under the influence of gravity, the process steam will naturally deposit downward, resulting in a higher etching rate of the wafers in the lower layer than that of the wafers in the upper layer.

[0039] The first intake air regulating mechanism 410 is disposed above the second intake air regulating mechanism 420; by means of the first regulator 412, the gap between the first regulating plates 411 is increased, and by means of the second regulator 422, the gap between the second regulating plates 421 is decreased. The process steam will preferentially flow through the first outlet air regulating mechanism 430, thereby increasing the process steam flow rate in the upper layer and promoting the etching of the wafers located in the upper layer; by means of the third regulator 432, the gap between the third regulating plates 431 is increased, and by means of the fourth regulator 442, the gap between the fourth regulating plates 441 is decreased. The process steam will preferentially flow through the first outlet air regulating mechanism 430, thereby preventing the process steam from depositing downward, and further optimizing the etching effects of the upper and lower wafers.

[0040] Specifically, reference can be made to Figure 1 , in the illustrated embodiment, the first intake air regulating mechanism 410 and the second intake air regulating mechanism 420 are disposed on the right side inside the chamber. The first air distribution plate 310 is located between the two intake air regulating mechanisms and the right chamber wall where the intake port 101 is located. The wafer holder 200 is located on the left side of the two intake air regulating mechanisms. The process steam flowing out uniformly through the first air holes can pass through the gaps between the regulating plates of the first intake air regulating mechanism 410 and the second intake air regulating mechanism 420 and flow to the etching area.

[0041] Continue to refer to Figure 1 , the first intake air regulating mechanism 410 includes a plurality of first regulating plates 411 arranged at intervals in the vertical direction. The second intake air regulating mechanism 420 includes a plurality of second regulating plates 421 arranged at intervals in the vertical direction. The first regulating plates 411 and the second regulating plates 421 are arranged side by side in the vertical direction. There is a gap for the process steam to flow through between any two adjacent regulating plates. Through the first regulating plates 411 and the second regulating plates 421, a grille-like wall is formed on the intake path of the process steam. When the process steam passes through, it will be dispersed into multiple airflows by the regulating plates, so as to form a stable laminar flow or quasi-laminar flow, thereby reducing turbulence and eddy currents, which is beneficial to improving the etching uniformity. It enables each stream of process steam to blow onto one layer of wafers and can also improve the air-receiving effect of the wafers.

[0042] The first regulator 412 and the second regulator 422 can adopt any regulating structure that is convenient for changing the gap between the plates. For example, an electric cylinder is combined with a connecting rod to cause the regulating plate to displace and change the distance, or the regulator is combined with the regulating plate to form a louver form, and the distance is changed by flipping the regulating plate.

[0043] The first regulator 412 can adjust the size of the gap between the first regulating plates 411 to control the flow rate of the process steam flowing to the upper layer area.

[0044] The second regulator 422 can adjust the size of the gap between the second regulating plates 421 to control the flow rate of the process steam flowing to the lower layer area.

[0045] The first intake air regulating mechanism 410 and the second intake air regulating mechanism 420 work together to more precisely regulate the flow rate and distribution of process steam entering the etching area, ensuring that the process steam acts more effectively on the upper wafer and slowing down the etching rate of the lower wafer.

[0046] Continue to refer to Figure 1 , the first exhaust gas regulating mechanism 430 and the second exhaust gas regulating mechanism 440 are arranged on the left side inside the chamber, near the exhaust gas outlet 102. The first exhaust gas regulating mechanism 430 and the first intake air regulating mechanism 410 are arranged opposite to each other in the left-right direction, and the second exhaust gas regulating mechanism 440 and the second intake air regulating mechanism 420 are also arranged opposite to each other in the left-right direction. The wafer holder 200 is located between the intake air regulating mechanism and the exhaust gas regulating mechanism. The unreacted process steam and the by-products generated by etching will flow out through the exhaust gas regulating mechanism along the exhaust gas outlet 102 and the exhaust gas pipeline under the influence of the pressure difference inside and outside the chamber.

[0047] Continue to refer to Figure 1 , the first exhaust gas regulating mechanism 430 includes a plurality of third regulating plates 431 arranged at intervals in the vertical direction, and the second exhaust gas regulating mechanism 440 includes a plurality of fourth regulating plates 441 arranged at intervals in the vertical direction. The third regulating plates 431 and the fourth regulating plates 441 are arranged side by side in the vertical direction, and there is a gap for the process steam and the by-products to flow through between any two adjacent regulating plates.

[0048] The third regulator 432 and the fourth regulator 442 can also adopt any adjustment structure that is convenient for changing the gap between the plates, and the details will not be elaborated here.

[0049] The third regulator 432 can adjust the size of the gap between the third regulating plates 431 to control the flow rate of the process steam and the by-products leading to the upper area.

[0050] The fourth regulator 442 can adjust the size of the gap between the fourth regulating plates 441 to control the flow rate of the process steam and the by-products leading to the lower area.

[0051] The first exhaust gas regulating mechanism 430 and the second exhaust gas regulating mechanism 440 work together to more precisely regulate the direction and flow rate of the process steam discharged, which is beneficial to preventing the process steam from depositing downward.

[0052] It should be added that when it is necessary to improve the problem of downward deposition of process steam, the gap between the first adjusting plates 411 can be increased only, or the gap between the second adjusting plates 421 can be decreased only, so as to promote the process steam to mainly flow to the upper layer area; or the gap between the third adjusting plates 431 can be increased only, or the gap between the fourth adjusting plates 441 can be decreased only, so as to promote the process steam in the cavity to flow upward to the upper layer area and then be discharged, thereby hindering the downward sinking of the process steam to a certain extent; the gap between the first adjusting plates 411 can be increased and the gap between the second adjusting plates 421 can be decreased, but the gaps between the third adjusting plates 431 and the fourth adjusting plates 441 remain unchanged; or the gap between the first adjusting plates 411 can be increased, the gap between the second adjusting plates 421 can be decreased, and at the same time the gap between the third adjusting plates 431 can be increased and the gap between the fourth adjusting plates 441 can be decreased. By making multiple sets of adjusting plates work together, the gap between the adjusting plates facing the upper layer area and the gap between the adjusting plates facing the lower layer area can be further widened, so as to better increase the steam concentration in the upper layer area, while promoting the etching of the upper layer wafers, slowing down the etching of the lower layer wafers, and then improving the etching uniformity of multiple wafers.

[0053] In a specific embodiment, the first adjusting plates 411 and the second adjusting plates 421 are equally spaced, and the third adjusting plates 431 and the fourth adjusting plates 441 are also equally spaced; the process steam (composed of hydrogen fluoride steam, gaseous ethanol and nitrogen) is introduced into the etching chamber 100 from the air inlet 101; the process steam first enters the first air chamber 103, diffuses in the first air chamber 103, and then uniformly flows out through the first air holes; the flowing-out process steam then enters the first air inlet adjusting mechanism 410 and the second air inlet adjusting mechanism 420, and flows to the etching area through the gap between the first adjusting plates 411 and the second adjusting plates 421; after the process steam contacts the silicon oxide material on the wafer surface, hydrogen fluoride reacts with silicon oxide to generate gaseous silicon tetrafluoride and water vapor. The gaseous by-products such as silicon tetrafluoride and water vapor generated by the reaction, as well as the process steam that has not participated in the reaction, will flow to and pass through the air outlet adjusting mechanism, and finally be discharged through the air outlet 102 to achieve the precise removal of silicon oxide; after etching for a period of time, the process steam has been deposited in the lower layer area; by the first adjuster 412, the gap between the first adjusting plates 411 is increased, and by the second adjuster 422, the gap between the second adjusting plates 421 is decreased, so that the process steam preferentially flows to the first air inlet adjusting mechanism 410, thereby increasing the process steam flow rate in the upper layer and promoting the etching of the upper layer wafers; at the same time, by the third adjuster 432, the gap between the third adjusting plates 431 is increased, and by the fourth adjuster 442, the gap between the fourth adjusting plates 441 is decreased, so that the process steam flowing to the air outlet 102 mainly flows to the first air outlet adjusting mechanism 430, thereby hindering the downward deposition of the process gas and slowing down the etching of the lower layer wafers, and optimizing the etching effects of the upper and lower layer wafers.

[0054] By adjusting the gap between the regulating plates at the air inlet end and / or the air outlet end, the gas flow path is changed, and the etching rates of the upper and lower wafers can be balanced.

[0055] In summary, the multi-wafer etching apparatus provided by the present application enables the process steam to act on multiple wafers uniformly through the cooperation of the first gas distribution plate 310 and the two groups of air inlet regulating mechanisms, which helps to improve the etching effect of each wafer; by adjusting the gap between the regulating plates at the air inlet end and / or the air outlet end, the gas flow direction and distribution can be changed, so as to balance the etching rates of the upper and lower wafers, reduce product quality problems caused by the difference in etching rates, and is beneficial to improving the consistency and yield rate of a batch of products.

[0056] Optionally, during the etching process, the air pressure in the chamber is maintained at 550 Torr.

[0057] The normal boiling point of ethanol is 78 °C. At 550 Torr, the boiling point of ethanol will decrease (about 55 - 65 °C), so as to maintain ethanol in a gaseous state, avoid incomplete vaporization of ethanol to form droplets, which may interfere with etching uniformity or cause side reactions (such as carbon-based contaminants).

[0058] In addition, at normal or high pressure, steam is more likely to deposit downward under the action of gravity due to density differences. The design of medium and low pressure (550 Torr) can reduce the gas density difference, weaken the influence of gravity on the steam distribution, and to a certain extent reduce the difference in etching rates between the upper and lower wafers.

[0059] In one embodiment, with reference to Figure 1 、 Figure 4 and Figure 5 , the first gas distribution plate 310 is arranged in a square frame shape. The top of the first gas distribution plate 310 is connected to the inner top wall of the etching chamber 100, and the bottom of the first gas distribution plate 310 is connected to the inner bottom wall of the etching chamber 100. The side of the first gas distribution plate 310 facing away from the air inlet 101 is open, and a plurality of regulating plates are arranged at intervals in the open side of the first gas distribution plate 310 in the vertical direction.

[0060] In this embodiment, there is also a gas distribution cavity between the first gas distribution plate 310 and the adjusting plates of the first intake air adjusting mechanism 410 and the second intake air adjusting mechanism 420. When the number of adjusting plates is more than the number of first air holes, the gas distribution cavity helps the process steam to diffuse towards the adjusting plates, avoiding the process steam flowing out mainly concentrating near the first air holes. In the present application, the spacing between the adjusting plates is variable. Assume that, in the initial state, a set of adjusting plates are evenly distributed along the vertical direction, and the intervals between the first air holes and the adjusting plates correspond one by one. Then, once the spacing between the adjusting plates is changed, the first air holes no longer face the intervals. When the first air holes face the intervals, the process steam flowing out through the first air holes can quickly, naturally, and accurately spray towards the wafer rack 200; when the first air holes no longer face the intervals, the first air holes will jet air towards the adjusting plates, affecting the flow of the process steam. Setting up the gas distribution cavity can play the role of storing gas and stabilizing pressure, and even if the first air holes no longer face the intervals, it can reliably guide the process steam to flow smoothly towards the intervals.

[0061] In this way, the first gas cavity 103, the first gas distribution plate 310, and the gas distribution cavity work together, enabling the process steam to evenly blow towards the entire wafer rack 200 and act on each layer of wafers, which is beneficial to improving the uniformity of etching multiple wafers.

[0062] In this embodiment, the first gas distribution plate 310 also provides positions for the installation of the adjusting plates and the adjusting drivers, avoiding high-intensity processing of the etching cavity 100, and making the pre-installation and post-maintenance of the equipment more convenient.

[0063] Optionally, multiple rows and columns of first air holes are provided on the first gas distribution plate 310, and the multiple first air holes are arranged in an array. At this time, the first air holes are distributed not only vertically but also horizontally. The first gas cavity 103 has more air outlet holes, and the process steam flowing through the first gas distribution plate 310 can flow out at more points, which is beneficial to improving the comprehensiveness of gas distribution.

[0064] Optionally, on the first gas distribution plate 310, the positions of the first air holes in the vertical direction are adjustable; the first air holes can change their positions following the first adjusting plate 411 and / or the second adjusting plate 421 to ensure that each first air hole always faces a gap formed by two adjusting plates spaced apart.

[0065] In one embodiment, the first gas distribution plate 310 includes a fixed main board and a movable auxiliary board. The fixed main board is hermetically connected to the etching cavity 100. A long hole extending in the vertical direction is provided on the fixed main board. The movable auxiliary board is slidably connected to the fixed main board. Multiple short holes spaced apart in the vertical direction are provided on the movable auxiliary board; the long hole and the short hole are opposite in position; the intervals between adjacent two short holes can block the long hole, and the positions where the long hole communicates with the short holes form the first air holes; by moving the movable auxiliary board in the vertical direction, the positions of the first air holes can be changed.

[0066] Furthermore, the movable auxiliary plate is composed of multiple small plates spliced together. Each small plate is provided with a first air hole, and a bellows is connected between two adjacent small plates to prevent process steam from flowing out of the parts other than the short holes; any small plate is connected to a first adjusting plate 411 or a second adjusting plate 421. In this way, the small plate can move up and down following the adjusting plate, and the position of the first air hole can follow accordingly.

[0067] Optionally, the adjusting plates at the air inlet end (the first adjusting plate 411 and the second adjusting plate 421) are always symmetrically arranged with the adjusting plates at the air outlet end (the third adjusting plate 431 and the fourth adjusting plate 441).

[0068] Specifically, reference can be made to Figure 1 , in the illustrated embodiment, the number and positions of the adjusting plates on the left and right sides correspond one by one, and the intervals between the adjusting plates at the air inlet end and the gaps between the adjusting plates at the air outlet end also correspond one by one.

[0069] The symmetrical arrangement of the adjusting plates on both sides provides a symmetrical and regular channel for the flow of gas. At the air inlet end, the symmetrical layout of the adjusting plates makes the process steam receive uniform resistance and the air flow direction is stable when flowing towards the etching area, which is beneficial to the formation of laminar flow or quasi-laminar flow. The stable laminar flow or quasi-laminar flow enables the process steam to act on each wafer evenly, which is beneficial to improving the etching uniformity. At the air outlet end, the symmetrical adjusting plates also ensure the smoothness and stability of gas discharge, avoiding the air flow disorder caused by local pressure changes. The symmetrical design of the adjusting plates on both sides can reduce the turbulence and eddy current phenomena of the air flow in the etching chamber 100, enable the process steam to act on the wafer more evenly, and enable the waste gas to be discharged more stably, thereby maintaining the stability of the gas environment in the etching chamber 100 and ensuring the consistency of the etching reaction.

[0070] The symmetrical layout of the adjusting plates optimizes the gas flow and management in both the air inlet and air outlet stages, so that the process steam can fully participate in the reaction. At the same time, the waste gas and by-products can be discharged in a timely and smooth manner to maintain a stable gas environment in the chamber.

[0071] The first regulator 412, the second regulator 422, the third regulator 432, and the fourth regulator 442 can adopt the same configuration, or can adopt different configurations according to the actual needs of installation and regulation.

[0072] Taking the first regulator 412 as an example for illustration.

[0073] In one embodiment, the first regulator 412 adopts a structure of a connecting rod with a collar. Specifically, a connecting rod is provided in the etching chamber 100, and the connecting rod extends in the vertical direction. A plurality of first adjusting plates 411 are inserted through the connecting rod. The lowermost first adjusting plate 411 is fixedly arranged, and the other first adjusting plates 411 can all slide along the connecting rod. A limiting collar is arranged between any two adjacent first adjusting plates 411, and the limiting collar is slidably arranged on the horizontal connecting rod. A traction rope is also arranged between any two connected first adjusting plates 411, and the length of the unfolded traction rope is greater than the length of the limiting collar.

[0074] When it is necessary to reduce the gap between the first adjusting plates 411, push the uppermost first adjusting plate 411 until it abuts against the limiting collar, and then continue to push the next first adjusting plate 411... In this way, until all the first adjusting plates 411 and the limiting collar are in contact with each other.

[0075] When it is necessary to increase the gap between the first adjusting plates 411, pull the uppermost first adjusting plate 411 to pull the traction rope, and then the next first adjusting plate 411 can be pulled up... In this way, until all the traction ropes are in a state of tensioning the first adjusting plates 411.

[0076] In another embodiment, an elastic member (such as a spring) and a limiting block are arranged between any two adjacent first adjusting plates 411. The lowermost first adjusting plate 411 is fixedly arranged, and the other first adjusting plates 411 can all move in the vertical direction.

[0077] When it is necessary to reduce the gap between the first adjusting plates 411, apply pressure to the uppermost first adjusting plate 411 to make it move downward. After the elastic member is compressed, it can press down the next first adjusting plate 411... In this way, until all the first adjusting plates 411 and the limiting block are in contact with each other.

[0078] When it is necessary to increase the gap between the first adjusting plates 411, remove the pressure on the uppermost first adjusting plate 411, and the elastic member will recover, so that all the first adjusting plates 411 can be reset.

[0079] This application does not limit the specific configuration of the regulator.

[0080] In a specific embodiment, the first regulator 412, the second regulator 422, the third regulator 432, and / or the fourth regulator 442 include: an adjustment rotating shaft 412a rotatably disposed in the etching chamber 100 and extending in the vertical direction. A plurality of sets of symmetrically distributed guiding grooves are provided on the adjustment rotating shaft 412a. A set of guiding grooves serving as the axis of symmetry extends horizontally along the circumferential direction of the adjustment rotating shaft 412a, and the other guiding grooves extend obliquely with respect to the axis of symmetry, and the inclination angles gradually increase from the axis of symmetry to both sides, forming a continuously changing layout; an adjustment driving member 412b for driving the adjustment rotating shaft 412a to rotate self; a plurality of adjustment sliders 412c, and one adjustment slider 412c is slidably disposed in any one of the guiding grooves, and any one of the adjustment sliders 412c is connected to an adjustment plate. When it is necessary to change the distribution of the intake or exhaust gas flow, the adjustment driving member 412b drives the adjustment rotating shaft 412a to rotate self, and the adjustment slider 412c can slide along the guiding groove. Affected by the layout of the guiding groove, a set of adjustment plates connected to the adjustment slider 412c can move in the vertical direction and change the distance. The different angles through which the adjustment rotating shaft 412a rotates result in different distances between the adjustment plates.

[0081] Specifically, reference may be made to Figures 1 to 6 , in the illustrated embodiment, the first regulator 412, the second regulator 422, the third regulator 432, and the fourth regulator 442 all adopt the adjustment rotating shaft 412a in combination with the adjustment driving member 412b; the first intake air adjustment mechanism 410 and the second intake air adjustment mechanism 420 are symmetrically disposed along the vertical direction, and the first exhaust gas adjustment mechanism 430 and the second exhaust gas adjustment mechanism 440 are symmetrically disposed along the vertical direction.

[0082] Taking the first regulator 412 as an example for illustration.

[0083] Figure 1 In the illustrated embodiment, the adjustment rotating shaft 412a of the first regulator 412 extends in the vertical direction, and the upper end passes through the etching chamber 100 and is connected to the adjustment driving member 412b disposed outside. The adjustment driving member 412b can adopt any driving structure such as a rotary cylinder or a motor that is convenient for driving the adjustment rotating shaft 412a to rotate. The adjustment driving member 412b is disposed outside the chamber, which is convenient for installation, maintenance, etc.

[0084] Continue to refer to Figure 6, the surface of the adjustment shaft 412a is provided with multiple groups of guide grooves, and the multiple groups of guide grooves are distributed in a symmetrical fan shape. The group of guide grooves located in the middle can be regarded as the symmetry axis in the fan shape, and the group of guide grooves extends horizontally along the circumference of the adjustment shaft 412a; the remaining guide grooves extend obliquely compared to the symmetry axis, and the farther away from the symmetry axis, the greater the inclination angle of the guide grooves (for example, the inclination angle of the group of guide grooves as the symmetry axis is 0°, the inclination angle of the adjacent guide grooves is 5°, and the inclination angles of the guide grooves outward are 10°, 15°...), thus forming a continuous gradient layout.

[0085] Combined with reference Figure 2 and Figure 6 Each set of guide grooves is slidably provided with an adjusting slider 412c, and the adjusting slider 412c can move along the guide grooves. Each adjusting slider 412c is connected to a first adjusting plate 411.

[0086] It is easy to imagine that if the movement direction of the first adjustment plate 411 is not restricted, the first adjustment plate 411 may rotate along with the adjustment slider 412c.

[0087] To this end, a vertically extending slide groove is provided on the inner wall of the etching chamber 100 or the side wall of the square frame-shaped first gas homogenizing plate 310, and at least one end of the first adjustment plate 411 is slidably disposed in the slide groove. The slide groove can limit the movement direction of the first adjustment plate 411, so that the first adjustment plate 411 can only move in the vertical direction when subjected to force.

[0088] Specifically, when the gap between the first adjustment plates 411 needs to be reduced, the adjustment drive member 412b drives the adjustment shaft 412a to rotate counterclockwise, so that the adjustment sliders 412c move from the inclined distal end to the proximal end, and the adjustment sliders 412c drive the first adjustment plates 411 to move closer to each other.

[0089] When the gap between the first adjustment plates 411 needs to be increased, the adjustment driving member 412b drives the adjustment shaft 412a to rotate clockwise, so that the adjustment sliders 412c spread from the inclined proximal end to the distal end, and the adjustment sliders 412c drive the first adjustment plates 411 to move away from each other.

[0090] Since the multiple groups of guide grooves are distributed in a symmetrical fan shape, it can be known that the further away from the proximal end, the larger the spacing between the first adjustment plates 411; similarly, the further away from the distal end, the smaller the spacing between the first adjustment plates 411. Therefore, in actual operation, the rotation angle of the adjustment shaft 412a can be controlled according to the flow distribution requirements, so that the adjustment slider 412c stays at different positions in the guide groove, so that the first adjustment plates 411 have different spacings, thereby meeting more diverse air intake or air outlet needs.

[0091] In addition, by controlling the inclination angle of the control guide grooves, the adjusting plates can be kept evenly spaced all the time, or the adjusting plates can be distributed at different intervals after the interval adjustment. For example, the inclination degree of the guide grooves arranged above the symmetry axis is greater than that of the guide grooves arranged below the symmetry axis; after the adjusting rotating shaft 412a rotates and the gap between the first adjusting plates 411 increases, from top to bottom, the intervals between the adjusting plates become smaller and smaller; in this way, the gas flow distribution can be further regulated, and the etching of the upper-layer wafers can be promoted better and more precisely.

[0092] Optionally, the multi-wafer etching device provided by the present application further includes a second gas distribution plate 320, which is arranged in the etching chamber 100 and near the air outlet 102; a plurality of second air holes are formed in the second gas distribution plate 320, and the plurality of second air holes are evenly spaced in the vertical direction; a second gas chamber 104 is formed between the second gas distribution plate 320 and the air outlet 102; the unreacted process steam and the by-products generated by etching will enter the second gas chamber 104 through the second air holes during the discharge process, and the second gas chamber 104 can buffer the pumping speed fluctuation and balance the pressure change, so as to maintain the air pressure stability in the etching chamber 100.

[0093] Specifically, reference can be made to Figure 1 and Figure 3 In the illustrated embodiment, the second gas distribution plate 320 and the first gas distribution plate 310 are symmetrically arranged in the left-right direction, and the structure of the second gas distribution plate 320 is similar to that of the first gas distribution plate 310, and will not be elaborated here. There is a gap between the second gas distribution plate 320 and the left side wall where the air outlet 102 is located, and the gap forms a sealed second gas chamber 104.

[0094] During the etching process, the unreacted process steam and the by-products generated by etching will flow from the etching area to the air outlet 102 under the influence of the pressure difference inside and outside the chamber generated by the pumping of the vacuum pumping device. During the outflow process, the gas will first pass through the gap between the third adjusting plate 431 and the fourth adjusting plate 441, and then contact the second gas distribution plate 320. The second gas distribution plate 320 can prevent the gas from directly rushing towards the air outlet 102, thereby stabilizing the air pressure near the air outlet 102. At the same time, the second air holes on the second gas distribution plate 320 can play a role in current limiting and flow splitting, so as to facilitate the gas to enter the second gas chamber 104 evenly. The second gas chamber 104 can use its own space volume to buffer the incoming gas.

[0095] When the vacuum pumping equipment is working, if the pumping speed fluctuates, the gas in the second air chamber 104 can supplement or adjust the pressure to a certain extent, avoiding large fluctuations in the air pressure in the etching chamber 100 caused by sudden changes in the pumping speed. For example, when the pumping speed suddenly increases, the gas stored in the second air chamber 104 can be quickly supplemented to prevent a sudden drop in the air pressure in the etching area; when the pumping speed decreases, the second air chamber 104 can temporarily store the excess gas to avoid a sudden increase in the air pressure in the etching area, thereby maintaining the air pressure stability in the etching chamber 100.

[0096] The setting of the second gas distribution plate 320 and the second air chamber 104 effectively solves the problem of air pressure fluctuation, which is beneficial to the etching reaction to proceed under a stable air pressure environment.

[0097] Optionally, the multi-wafer etching device provided by the present application further includes a temperature control mechanism, which is used to heat the etching chamber 100 so that the temperature in the etching chamber 100 is maintained at 60 °C.

[0098] The VHF process has a risk of low-temperature liquefaction corrosion. Maintaining the environmental temperature in the etching chamber 100 at 60 °C can effectively maintain the gaseous state of the process steam and ensure the continuous and normal progress of the etching.

[0099] The temperature control mechanism can adopt any structure capable of realizing heating, such as a heating rod, an electric heating wire, etc.

[0100] Due to the risk of corrosion in the chamber, the temperature control mechanism is preferably arranged outside the chamber or in the chamber wall.

[0101] Optionally, the temperature control mechanism includes a heating tape, and heating tapes are attached to the outer walls of the etching chamber 100 to comprehensively heat the etching chamber 100 and ensure that the temperature inside the etching chamber 100 is uniform everywhere.

[0102] Specifically, a resistance wire is provided inside the heating tape. After the resistance wire is energized, heat will be generated, and the heat can be transferred to the chamber wall in contact with it through heat conduction, so as to increase the temperature inside the chamber from the outside to the inside. During the etching process, the heating tape works continuously and can automatically adjust the heating power according to the temperature data fed back by the temperature sensor in the etching chamber 100 to ensure that the temperature inside the etching chamber 100 always remains at the set 60 °C, providing a stable temperature environment for wafer etching.

[0103] More specifically, to ensure the comprehensiveness of heating, except for the parts where the material inlets and outlets (such as wafer inlets and outlets, air inlet 101, air outlet 102) are opened on the outer wall of the etching chamber 100, the outer wall of the etching chamber 100 is covered with heating tapes. By arranging heating tapes on the outer wall of the etching chamber 100 in an all-round way, heat can be transferred to the inside of the etching chamber 100 more evenly, avoiding problems such as local overheating or overcooling.

[0104] A stable and uniform temperature environment also helps the chemical reaction between process steam and the wafer surface to proceed stably, which is conducive to improving the accuracy and consistency of etching.

[0105] Optionally, the heating tape is firmly attached to the outer wall of the etching chamber 100 through a high-temperature resistant adhesive to ensure the maximization of the heat transfer efficiency between the heating tape and the outer wall.

[0106] Optionally, a heating tape is attached to the intake pipe.

[0107] Hydrofluoric acid is highly corrosive, especially liquid hydrofluoric acid, but the corrosiveness of gaseous hydrofluoric acid (such as hydrogen fluoride vapor) is weakened. By setting a heating tape on the intake pipe and using the heating tape to keep the intake pipe at a relatively high temperature (above 55 °C), it is possible to prevent the process steam from liquefying when flowing through.

[0108] During the etching process, the heating tape on the intake pipe works continuously to ensure that the process steam remains in a gaseous state during transportation, thereby reducing the corrosion risk of liquid hydrofluoric acid and ensuring that the process steam can stably enter the etching chamber 100 and participate in the reaction.

[0109] Optionally, a heating tape is attached to the outlet pipe.

[0110] During the discharge of by-products generated by etching and unreacted process steam, if they are liquefied when cooled, there is not only a corrosion risk, but also a possibility of blocking the outlet pipe and affecting the vacuum pumping effect. In severe cases, it may even lead to equipment failure.

[0111] By setting a heating tape on the outlet pipe, it is possible to effectively prevent gas condensation and ensure smooth exhaust.

[0112] Optionally, the heating tape is wound along the outer wall of the pipe and is focused on covering key parts of the pipe (such as connection parts and bends where temperature reduction is likely to occur) to ensure that the entire pipe can be fully heated.

[0113] Optionally, the intake pipe and / or the outlet pipe is a double-layer pipe. The inner pipe is used for ventilation, and the heating tape is set between the inner and outer pipes; the space between the inner and outer pipes is evacuated, or the space between the inner and outer pipes is filled with heat-insulating materials, which is beneficial to reducing heat dissipation and maintaining the heating effect.

[0114] Optionally, the temperature control mechanism further includes heating wires. The etching chamber 100 includes an outer jacket and an inner lining. The outer jacket is made of a metal material, and the inner lining is made of a high-temperature resistant and corrosion resistant material. The heating wires are embedded between the outer jacket and the inner lining.

[0115] Specifically, the outer jacket is made of stainless steel (such as 316L) or aluminum alloy, which has the advantages of high mechanical strength, low cost, and easy processing.

[0116] The inner lining is made of quartz or nickel-based alloy (such as Hastelloy C-276). In this way, even when the inner lining is in direct contact with corrosive gases (such as HF, ethanol), it is not easily eroded. At the same time, quartz can withstand temperatures exceeding 1000°C, or nickel-based alloy can withstand temperatures exceeding 500°C, which is safer to be used in a cavity that needs to be heated.

[0117] The quartz inner lining can be fixed in the outer casing by mechanical clamps or high-temperature resistant adhesives; the nickel-based alloy inner lining can be connected to the outer casing by welding or bolts. The inner lining completely covers the inner wall of the outer casing to prevent corrosive gases from contacting the outer casing.

[0118] Install the heating wire between the outer casing and the inner lining, which neither hinders the heating of the inner lining and the inner cavity, nor exposes the heating wire to the corrosive environment or exposes it outside, resulting in heat spillage and affecting the heating effect.

[0119] Optionally, the heating wire is distributed in a mesh or spiral shape, which can fully cover the inner lining and ensure the heating uniformity.

[0120] Optionally, the etching chamber 100 is divided into multiple heating zones (such as the top, bottom, left, and right), and each heating zone is equipped with a set of independent PID controllers and thermocouples, which can real-time feedback the temperature at each position to facilitate the targeted adjustment of the power of the temperature control mechanism.

[0121] Optionally, a lifting and moving cavity 510 is provided below the etching chamber 100. A lifting platform 520 is provided in the lifting and moving cavity 510, and the wafer rack 200 is arranged on the lifting platform 520; after etching a batch of wafers, the lifting platform 520 descends with the wafer rack 200, so that the wafer rack 200 enters the lifting and moving cavity 510. There is a wafer inlet and outlet on the lifting and moving cavity 510. Through the wafer inlet and outlet, the unloading of the etched wafers and the loading of the wafers to be etched can be realized; after the wafer rack 200 loads the wafers to be etched, the lifting platform 520 ascends with the wafer rack 200, so that the wafer rack 200 enters the etching chamber 100 to facilitate the wafers to be etched.

[0122] Specifically, refer to Figure 7 , in the illustrated embodiment, the bottom of the etching chamber 100 is connected to the lifting and moving cavity 510, and the lifting platform 520 can move between the two cavities through vertical displacement. The lifting and moving cavity 510 can accommodate the lifting platform 520 and the wafer rack 200, providing an operating space for the loading and unloading of wafers. There is a wafer inlet and outlet on one side of the lifting and moving cavity 510, and an external wafer loading and unloading device (such as a manipulator) can interact inside and outside through the wafer inlet and outlet.

[0123] The wafer carrier 200 holds a batch of wafers. After etching is completed in the etching chamber 100, the lifting platform 520 descends, causing the wafer carrier 200 to enter the lifting cavity 510. Through the wafer inlet and outlet, the wafer loading and unloading equipment can take out the etched wafers. After a batch of wafers is taken out, the wafer loading and unloading equipment can place new wafers to be etched into the lifting cavity 510. After the wafer carrier 200 holds a new batch of wafers, the lifting platform 520 ascends, causing the wafer carrier 200 to enter the etching chamber 100.

[0124] It is easy to understand that if wafer loading and unloading operations are performed inside the etching chamber 100, it may affect parameters such as the gas environment and temperature inside the chamber, thereby interfering with the stability of etching. By setting up the lifting cavity 510 and transferring the loading and unloading operations to the lifting cavity 510, it is possible to avoid setting the wafer inlet and outlet on the etching chamber 100, thus solving problems such as air leakage, heat dissipation, and uneven temperature in the etching area caused by the existence of the wafer inlet and outlet.

[0125] Optionally, the wafer carrier 200 is detachably arranged on the lifting platform 520; the wafer carrier 200 carrying the etched wafers is unloaded to achieve rapid unloading; the wafer carrier 200 carrying the wafers to be etched is loaded to achieve rapid loading.

[0126] Making the wafer carrier 200 detachable from the lifting platform 520. After etching is completed, when the wafer carrier 200 descends into the lifting cavity 510, the wafer carrier 200 can be removed through the wafer inlet and outlet, and all the wafers can be taken out at the same time. Then, a new wafer carrier 200 carrying the wafers to be etched is loaded into the lifting platform 520, and the next round of etching can start immediately.

[0127] The detachable design in combination with the lifting function enables rapid loading and unloading of wafers, which can shorten the replacement time of each batch of wafers, thereby improving the overall production efficiency.

[0128] In one embodiment, there are clamping blocks on the lifting platform 520, and the shape of the clamping blocks can be a right trapezoid or an L shape; there are clamping grooves at the bottom of the wafer carrier 200. During installation, align the clamping grooves at the bottom of the wafer carrier 200 with the clamping blocks, press down and push the wafer carrier 200, and the clamping blocks will be snapped into the clamping grooves to complete the installation. During disassembly, push the wafer carrier 200 in the reverse direction to make the clamping blocks disengage from the clamping grooves, and the wafer carrier 200 can be removed from the lifting platform 520.

[0129] In another embodiment, there are multiple groups of threaded holes corresponding to each other on the lifting platform 520 and the wafer carrier 200. During installation, align the threaded holes on the lifting platform 520 with the threaded holes on the wafer carrier 200, and the two can be tightened using screws. During disassembly, unscrew the screws to separate the wafer carrier 200 and the lifting platform 520.

[0130] In another embodiment, one of the lifting platform 520 and the wafer holder 200 is provided with a magnet, and the other is provided with a metal sheet. During installation, the magnet attracts the metal sheet to fix the two. During disassembly, the fixing between the two can be released by applying an external force to overcome the magnetic attraction force.

[0131] This application does not limit the specific connection method between the wafer holder 200 and the lifting platform 520.

[0132] Optionally, the lifting platform 520 includes: a platform part 521 for installing the wafer holder 200 and capable of making a lifting movement under the drive of a lifting driver; a cover part 522 provided directly above the platform part 521; a connecting rod 523 for connecting the platform part 521 and the cover part 522; when the wafer holder 200 is placed on the lifting platform 520, the wafer holder 200 is located between the platform part 521 and the cover part 522.

[0133] Among them, the lifting driver can adopt any structure such as an oil cylinder or an electric cylinder that can drive the platform part 521 to make a lifting movement in the vertical direction. The lifting driver can be arranged inside the lifting cavity 510 (during the etching process, the lifting cavity 510 is isolated from the etching cavity 100, and the process steam will not enter the lifting cavity 510, so the lifting driver will not be corroded), or it can be arranged outside the lifting cavity 510.

[0134] Specifically, reference can be made to Figure 7 , in the illustrated embodiment, the platform part 521 and the cover part 523 are arranged opposite to each other in the vertical direction, and the two are fixed by three groups of connecting rods 523. One group of connecting rods 523 is arranged on the side of the platform part 521 away from the wafer inlet and outlet, and the other two groups of connecting rods 523 are arranged opposite to each other in the left-right direction. During loading, the wafer holder 200 is fed between the platform part 521 and the cover part 523 through the wafer inlet and outlet. The wafer holder 200 can pass between the two groups of left and right connecting rods 523 and abut against the opposite group of connecting rods 523. Making the wafer holder 200 abut against the connecting rod 523 can indicate that the placement is in place.

[0135] Optionally, the multi-wafer etching device further includes an auxiliary gas supply pipeline, which is arranged in the lifting platform 520 and communicates with the process steam supply device; the bottom surface of the cover part 522 facing the platform part 521 is provided with a first air outlet hole, and the first air outlet hole communicates with the auxiliary gas supply pipeline, and / or the side surface of the connecting rod 523 facing the wafer holder 200 is provided with a second air outlet hole, and the second air outlet hole communicates with the auxiliary gas supply pipeline; during the etching process, the process steam can be sprayed onto the wafer through the first air outlet hole and / or the second air outlet hole.

[0136] In one embodiment, a plurality of first air outlets are provided on the bottom surface of the cover portion 522, and the plurality of first air outlets are equidistantly arranged along the circumferential direction inside; the diameter of the circle where the plurality of first air outlets are located is slightly larger than the diameter of the wafer. When the process steam is ejected through the first air outlets, a curtain of air can be formed to act on the wafer comprehensively. At the same time, the process steam ejected through the first air outlets mainly acts on the upper-layer wafer, which can promote the etching of the upper-layer wafer more precisely.

[0137] When a plurality of sets of connecting rods 523 are provided between the table portion 521 and the cover portion 523, the second air outlets can be opened only on one set of connecting rods 523, or the second air outlets can be opened on each of the plurality of sets of connecting rods 523. Increasing the number of connecting rods 523 with the second air outlets opened can optimize the coverage range of the process steam and improve the air-receiving effect of the wafer.

[0138] In one embodiment, referring to Figure 7 , three sets of connecting rods 523 are provided between the table portion 521 and the cover portion 523. A plurality of second air outlets are provided on one set of connecting rods 523 located on the side of the table portion 521 away from the wafer inlet and outlet. The plurality of second air outlets are equidistantly distributed in the vertical direction, and any one of the second air outlets is aligned with a wafer. When each wafer in the wafer rack 200 is directly opposite a second air outlet, the process steam is ejected from the second air outlet, and each wafer can receive air nearby, thereby comprehensively improving the etching efficiency. The second air outlets can also be opened only corresponding to the upper-layer wafers. When needed, the upper-layer wafers can be supplemented with air through the second air outlets, which can promote the etching of the upper-layer wafers.

[0139] In a specific embodiment, the first air outlets are provided on the bottom surface of the cover portion 522, and the second air outlets are provided on the side surfaces of the connecting rods 523. The table portion 521, the connecting rods 523, and the cover portion 522 are all hollow structures, and the hollow inner cavities of the three are interconnected. At this time, the interconnected hollow inner ring constitutes an auxiliary air supply pipeline. A valve is provided on the auxiliary air supply pipeline. When air supplementation is needed, the valve is opened, and the process steam can then enter the connecting rods 523 and the cover portion 522 along the auxiliary air supply pipeline, and finally be ejected towards the wafer through the first air outlets and the second air outlets.

[0140] In actual use, it may be only necessary to eject air from the first air outlets, or it may be only necessary to eject air from the second air outlets, or it may be necessary to eject air from the first air outlets and the second air outlets at different times.

[0141] At this time, two hollow flow channels can be constructed in the table portion 521, the connecting rods 523, and the cover portion 522 as the auxiliary air supply pipelines. One of the hollow flow channels is connected to the first air outlets, and the other hollow flow channel is connected to the second air outlets; a valve is provided on each of the two hollow flow channels, and the corresponding valve can be opened according to needs for air ejection.

[0142] In another embodiment, the base portion 521, the connecting rod 523, and the cover portion 522 are all hollow structures. The auxiliary air supply pipe is a flexible pipe, which is inserted into the hollow inner cavities of the three. At this time, two groups of flexible pipes are inserted into the lifting platform 520. One group of flexible pipes is connected to the first air outlet hole, and the other flexible pipe is connected to the second air outlet hole; a valve is provided on each of the two flexible pipes, and the corresponding valve can be opened as needed to blow air.

[0143] During the simultaneous etching of multiple wafers, affected by gravity, the process steam will deposit downward, resulting in a higher etching rate of the lower wafer than that of the upper wafer. By providing the first air outlet hole in the cover portion 522, targeted air supply can be carried out for the upper wafer. By increasing the process steam flow rate around the upper wafer, the etching efficiency of the upper and lower wafers can be optimized, and the etching difference can be reduced. When the second air outlet hole is provided only corresponding to the upper wafer, a similar effect can also be achieved.

[0144] The traditional etching method may also cause inconsistent etching degrees between wafers. By providing the second air outlet hole on the connecting rod 523 and making the second air outlet hole correspond to the wafers one by one, each wafer can be blown more precisely with the process steam, which is beneficial to improving the etching effect of the wafers and ensuring the etching uniformity of the wafers.

[0145] Setting the first air outlet hole and the second air outlet hole increases the blowing path of the process steam, which can increase the contact area and reaction opportunity between the wafer and the process steam. Especially for the etching of the upper wafer, it has a promoting effect, can effectively improve the overall etching efficiency, and is beneficial to shortening the etching time.

[0146] Optionally, a communication channel is provided between the etching chamber 100 and the lifting chamber 510. The lifting platform 520 and the wafer rack 200 can move between the etching chamber 100 and the lifting chamber 510 through the communication channel; after the lifting platform 520 carries the wafer rack 200 into the etching chamber 100, the base portion 521 can seal the communication channel, thereby preventing the process steam from entering the lifting chamber 510; after the lifting platform 520 carries the wafer rack 200 into the lifting chamber 510, the cover portion 523 can seal the communication channel to avoid interference between the processing operations in the lifting chamber 510 and the etching chamber 100.

[0147] Specifically, reference can be made to Figure 7 In the illustrated embodiment, the base portion 521 and the cover portion 523 are symmetrically arranged along the vertical direction, and both are arranged in a frustum shape. The communication channel is a cylindrical channel, and the inner diameter of the communication channel is smaller than the outer diameters of the base portion 521 and the cover portion 523, so that the base portion 521 and the cover portion 523 cannot enter the communication channel. When the lifting platform 520 rises, the base portion 521 can abut against the communication channel from bottom to top, thereby indicating that the rising is in place. When the lifting platform 520 descends, the cover portion 523 can abut against the communication channel from top to bottom, thereby indicating that the descending is in place.

[0148] To improve the sealing performance between the table part 521 and the connection channel and between the cover part 523 and the connection channel when they are in contact, sealing rings can be embedded on the front side where the table part 521 contacts the connection channel and on the back side where the cover part 523 contacts the connection channel. When the sealing rings are compressed and deformed, they can compensate for the possible gaps after contact, thus ensuring the sealing effect.

[0149] During the etching process, the table part 521 seals the connection channel, which can not only prevent the process steam from entering the lifting cavity 510, thereby protecting the equipment components in the lifting cavity 510, but also ensure the stability of the process environment in the etching chamber 100 so that the etching can proceed normally.

[0150] When loading and unloading the wafer, the cover part 523 seals the connection channel, separating the etching chamber 100 from the lifting cavity 510. In the independently sealed etching chamber 100, operations such as cleaning and process pretreatment can be carried out, such as cleaning the residual process steam and by-products, inspecting and adjusting the equipment in the chamber, etc. The processing operations in the two chambers do not interfere with each other, which helps to improve the operation synchronization of the equipment and reduce the idle time of the equipment.

[0151] Optionally, a cover is provided at the top of the wafer rack 200, and auxiliary air holes are provided on the side of the cover facing the wafer, and the auxiliary air holes are connected to the process steam supply equipment.

[0152] The cover is provided with auxiliary air holes, which is similar to the first air outlet provided on the cover part 522 in the above text, and its function is to supplement gas to the upper-layer wafer specifically. Details are not described again.

[0153] In one embodiment, the total etching duration is 2N. After the etching duration exceeds N, at the gas inlet end, the gap between the first adjusting plates 411 is increased and the gap between the second adjusting plates 421 is decreased; at the gas outlet end, the gap between the third adjusting plates 431 is increased and the gap between the fourth adjusting plates 441 is decreased. At the same time, the auxiliary air holes are enabled, so that the process steam sprays downward onto the wafer, which can effectively improve the etching difference between the upper and lower layers of wafers.

[0154] In a specific embodiment, for the VHF process, the total process duration is 5 min. After etching for 3 min, from bottom to top, the etching rate of the wafer significantly becomes slower and slower. The gap between the first adjusting plates 411 is increased to increase the amount of process steam flowing toward the upper-layer wafer; the gap between the second adjusting plates 421 is decreased to reduce the amount of process steam flowing toward the lower-layer wafer; at the same time, the gap between the third adjusting plates 431 is increased and the gap between the fourth adjusting plates 441 is decreased to maintain the stability of the gas flow. After etching for 5 min, the measurement results show that the overall etching rate is basically flat, the difference is very small, and the single-wafer etching uniformity is also improved, all within 5%.

[0155] In another embodiment, in the VHF process, the total process duration is 5 minutes. After etching for 3 minutes, from bottom to top, the etching rate of the wafer significantly becomes slower and slower. The auxiliary air holes are enabled so that the process steam sprays onto the wafer from top to bottom. After etching for 5 minutes, the measurement results show that the overall etching rate is basically flat and the uniformity is also improved, all being below 5%.

[0156] In yet another embodiment, in the VHF process, the total process duration is 5 minutes. After etching for 3 minutes, from bottom to top, the etching rate of the wafer significantly becomes slower and slower. The gap between the first adjusting plates 411 is increased, the gap between the second adjusting plates 421 is decreased, the gap between the third adjusting plates 431 is increased, and the gap between the fourth adjusting plates 441 is decreased. At the same time, the auxiliary air holes are enabled so that the process steam sprays onto the wafer from top to bottom. After etching for 5 minutes, the measurement results show that the overall etching rate is basically flat, the difference is very small, and the etching uniformity of a single wafer is also improved, all being below 3%.

[0157] The above embodiments only represent several implementation manners of the present application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patented application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A multi-wafer etching device, characterized in that: include: An etching chamber, with an air inlet on one side and an air outlet on the other side opposite thereto; The wafer rack is arranged in the etching chamber and is a multi-layer support structure; A first air intake regulating mechanism is provided in the etching chamber and located at one side of the air intake port, the first air intake regulating mechanism comprises a plurality of first regulating plates and a first regulator, the plurality of first regulating plates are arranged at intervals in the vertical direction, and the first regulator is used to adjust the gap between the first regulating plates; A second air intake regulating mechanism is also arranged in the etching chamber and located at one side of the air intake port, the second air intake regulating mechanism comprises a plurality of second regulating plates and a second regulator, the plurality of second regulating plates are arranged at intervals in the vertical direction, the second regulator is used to adjust the gap between the second regulating plates, and the first regulating plate and the second regulating plate are arranged side by side in the vertical direction; A first gas outlet regulating mechanism is disposed in the etching chamber and adjacent to the gas outlet, the first gas outlet regulating mechanism comprises a plurality of third regulating plates and a third regulator, the plurality of third regulating plates are arranged at intervals in the vertical direction, the third regulator is used to adjust the gap between the third regulating plates, the first regulating plate and the third regulating plate are arranged opposite to each other in the horizontal direction, and the wafer rack is located between the first regulating plate and the third regulating plate; The second gas outlet regulating mechanism is also arranged in the etching chamber and adjacent to the gas outlet. The second gas outlet regulating mechanism includes a plurality of fourth regulating plates and a fourth regulator. The plurality of fourth regulating plates are arranged at intervals in the vertical direction. The fourth regulator is used to adjust the gap between the fourth regulating plates. The second regulating plate and the fourth regulating plate are arranged opposite to each other in the horizontal direction. The wafer rack is located between the second regulating plate and the fourth regulating plate. The third regulating plate and the fourth regulating plate are arranged side by side in the vertical direction.

2. The multi-wafer etching device according to claim 1, characterized in that: The first regulator, the second regulator, the third regulator and / or the fourth regulator include: An adjusting shaft is rotatably disposed in the etching chamber and extends in a vertical direction. The adjusting shaft is provided with a plurality of symmetrically distributed guide grooves. A group of guide grooves serving as a symmetry axis extends horizontally along the circumference of the adjusting shaft. The other guide grooves extend obliquely relative to the symmetry axis, and the inclination angle increases gradually from both sides of the symmetry axis to form a continuously gradient layout. An adjusting driving member, used for driving the adjusting shaft to rotate; A plurality of adjusting sliders, wherein one adjusting slider is slidably disposed in any of the guide grooves, and any of the adjusting sliders is connected to an adjusting plate; When the distribution of the inlet or outlet air flow needs to be changed, the adjustment shaft is driven to rotate by the adjustment drive member, and the adjustment slider can slide along the guide groove. Under the influence of the guide groove layout, a set of adjustment plates connected to the adjustment slider can move in the vertical direction and change the spacing.

3. The multi-wafer etching device according to claim 1, characterized in that: Also includes: A first air-distributing plate is disposed in the etching chamber and adjacent to the air inlet. A plurality of first air holes are formed on the first air-distributing plate. The plurality of first air holes are evenly spaced in the vertical direction. A first air cavity is formed between the first air-distributing plate and the air inlet. The first air inlet regulating mechanism and the second air inlet regulating mechanism are both located on a side of the first air-distributing plate away from the air inlet. A second gas uniforming plate is arranged in the etching chamber and adjacent to the gas outlet. A plurality of second air holes are opened on the second gas uniforming plate. The plurality of second air holes are evenly spaced along the vertical direction. A second air cavity is formed between the second gas uniforming plate and the gas outlet.

4. The multi-wafer etching device according to claim 1, characterized in that: It also includes a temperature control mechanism, which is used to heat the etching chamber to maintain the temperature in the etching chamber at 60° C. The temperature control mechanism comprises a heating belt, and each outer wall of the etching chamber is attached with the heating belt, so as to fully heat the etching chamber and ensure that the temperature in the etching chamber is uniform everywhere.

5. The multi-wafer etching device according to claim 4, characterized in that: The air inlet is connected to the process steam supply equipment through the air inlet pipe, and the air outlet is connected to the vacuum equipment through the air outlet pipe. The heating belt is also attached to the air inlet pipe and / or the air outlet pipe; And / or, the temperature control mechanism also includes a heating wire, the etching chamber includes an outer jacket and an inner liner, the outer jacket is made of metal material, the inner liner is made of high temperature resistant and corrosion resistant material, and the heating wire is embedded between the outer jacket and the inner liner.

6. The multi-wafer etching device according to claim 1, characterized in that: A lifting activity chamber is provided below the etching chamber, a lifting platform is provided in the lifting activity chamber, and the wafer is mounted on the lifting platform; After a batch of wafers are etched, the lifting platform and the wafer rack are lowered, so that the wafer rack enters the lifting activity chamber. The lifting activity chamber is provided with a wafer inlet and outlet, through which the unloading of etched wafers and the loading of wafers to be etched can be realized; After the wafer rack is loaded with the wafer to be etched, the lifting platform carries the wafer rack up, so that the wafer rack enters the etching chamber, so that the wafer can be etched.

7. The multi-wafer etching device according to claim 6, characterized in that: The wafer rack is detachably arranged on the lifting platform; Unloading the wafer rack carrying the etched wafers to achieve rapid unloading; The wafer rack carrying the wafer to be etched is loaded to achieve rapid loading.

8. The multi-wafer etching device according to claim 7, characterized in that: The lifting platform comprises: A platform portion, used for mounting the wafer rack, and capable of performing lifting motion driven by a lifting drive; A cover portion, disposed directly above the platform portion; A connecting rod, used to connect the platform portion and the cover portion; When the wafer rack is placed on the lifting platform, the wafer rack is located between the platform and the cover; The multi-wafer etching device further comprises an auxiliary gas supply pipeline, which is arranged in the lifting platform and connected to the process steam supply equipment; The bottom surface of the cover facing the platform is provided with a first air outlet, the first air outlet is connected to the auxiliary air supply pipeline, and / or the side surface of the connecting rod facing the wafer rack is provided with a second air outlet, the second air outlet is connected to the auxiliary air supply pipeline; During the etching process, process steam can be sprayed toward the wafer through the first gas outlet hole and / or the second gas outlet hole.

9. The multi-wafer etching device according to claim 8, characterized in that: A communication channel is provided between the etching chamber and the lifting and moving chamber, and the lifting platform and the wafer rack can move between the etching chamber and the lifting and moving chamber through the communication channel; After the lifting platform carries the wafer rack into the etching chamber, the platform portion can seal the communication channel to prevent process steam from entering the lifting activity chamber; After the lifting platform carries the wafer rack into the lifting activity chamber, the cover can seal the communication channel to avoid interference between the processing operations in the lifting activity chamber and the etching chamber.

10. The multi-wafer etching device according to claim 1, characterized in that: A cover is provided on the top of the wafer rack, and an auxiliary air hole is provided on a side of the cover facing the wafer, and the auxiliary air hole is connected to a process steam supply device; The total etching time is 2N. After the etching time exceeds N, at the air inlet end, the gap between the first adjustment plates is increased and the gap between the second adjustment plates is decreased. At the air outlet end, the gap between the third adjustment plates is increased and the gap between the fourth adjustment plates is decreased. At the same time, the auxiliary air holes are enabled to allow the process steam to spray toward the wafer from top to bottom, which can effectively improve the etching difference between the upper and lower wafers.

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