Etching machine capable of regulating gas flow, and etching method

Abstract

An etching machine capable of regulating gas flow, and an etching method using the described etching machine capable of regulating gas flow. The etching machine comprises: a reaction chamber (101), a nozzle (139), a wafer stage and a gas flow control system. The gas flow control system comprises: a first gas flow baffle ring (117), the first gas flow baffle ring (117) being arranged in the reaction chamber (101) and being located between the nozzle (139) and the wafer stage, and a vent hole being provided at the position of the first gas flow baffle ring (117) opposite to the nozzle (139). In the etching machine, the first gas flow baffle ring (117) is provided to gather gas flow towards the center and above a wafer, so as to allow same to react with the wafer more directly, thereby improving the etching uniformity.

Description

Etching machine with adjustable airflow and etching method

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on June 29, 2023, with application number 202310800841.X and invention name “An etcher and etching method with adjustable airflow”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention relates to the technical field of etching machines, and in particular to an etcher with adjustable airflow and an etching method. Background Art

[0003] Plasma etchers, also known as plasma planar etchers, plasma etchers, plasma surface treatment equipment, or plasma cleaning systems, are used in the semiconductor industry. Inductively coupled plasma etching is the result of a combination of chemical and physical processes. Its basic principle is that under vacuum and low pressure, the radio frequency generated by the ICP radio frequency power supply is output to a ring-shaped coupling coil. A certain proportion of mixed etching gas is coupled through glow discharge to produce a high-density plasma. Under the action of the RF radio frequency of the lower electrode, this plasma bombards the substrate surface, breaking the chemical bonds of the semiconductor in the substrate pattern area, generating volatile substances with the etching gas, which then detach from the substrate in the form of gas and are extracted from the vacuum line.

[0004] Etching equipment requires airflow directed toward the wafer during the process. Different areas of the wafer are exposed to airflow directed downward and at certain angles. Existing airflow structures are typically unadjustable or have limited adjustment, and the RF coil is fixed. Consequently, poor etching uniformity is often not significantly improved.

[0005] Current plasma etchers, due to limitations such as their overall structure, have uneven plasma density and distribution, with airflow dispersed throughout the chamber. This results in poor wafer etching uniformity. Due to the fixed RF structures, such as the plasma coupling coil and air nozzle, significant improvements in uniformity are difficult to achieve. For example, the uniformity of aluminum etchers currently on the market is generally above 8%. Furthermore, the airflow is dispersed and unfocused, with some airflow being directly pumped away by the pump, resulting in unnecessary waste.

[0006] Summary of the Invention

[0007] In view of this, the present invention provides an etcher with adjustable airflow to solve the technical problem of poor uniformity of existing etchers.

[0008] The present invention also provides an etching method using the above-mentioned etcher with adjustable airflow.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] An etcher with adjustable airflow comprises: a reaction chamber, a nozzle, a wafer carrier and an airflow control system; the airflow control system comprises: a first airflow baffle ring; the first airflow baffle ring is arranged in the reaction chamber and is located between the nozzle and the wafer carrier; a vent hole is provided at a position opposite to the nozzle of the first airflow baffle ring.

[0011] Preferably, the first airflow baffle ring is a circular ring, the outer diameter of which matches the inner diameter of the chamber liner in the reaction chamber, and a gap is left between the outer circle of the first airflow baffle ring and the chamber liner to prevent particle aggregation.

[0012] Preferably, the airflow control system further comprises: a first lifting device; the first lifting device can enable the first airflow baffle ring to move up and down.

[0013] Preferably, the first lifting mechanism includes: a first lifting drive and a first transmission mechanism; the first transmission mechanism is located between the wafer carrier and the reaction chamber; and the first lifting drive is arranged outside the reaction chamber.

[0014] Preferably, the first transmission mechanism includes: a first baffle ring lifting rod and a first guide sleeve; the first end of the first baffle ring lifting rod is connected to the first airflow baffle ring, and the second end of the first baffle ring lifting rod is connected to the first lifting drive; the middle part of the first baffle ring lifting rod is arranged in the first guide sleeve, and the first guide sleeve is arranged on the inner surface of the chamber substrate in the reaction chamber, and is located between the wafer carrier and the reaction chamber.

[0015] Preferably, the first transmission mechanism also includes: a first adjustment block and a first fixed seat; the first end of the first baffle ring lifting rod is connected to the first end face of the first adjustment block through the first adjustment block screw, the second end face of the first adjustment block is connected to the first airflow baffle ring through the first fixing screw, and the second end of the first baffle ring rod is connected to the first lifting drive through the first fixed seat.

[0016] Preferably, the airflow control system further comprises: a superimposed baffle ring; the outer circle of the superimposed baffle ring is detachably mounted on the inner circle of the first airflow baffle ring.

[0017] Preferably, the number of the stacked baffle rings is multiple, with inner and outer arrangements. The outer circle of the inner stacked baffle ring can be detachably mounted on the inner circle of the outer stacked baffle ring, and the outer circle of the outermost stacked baffle ring can be detachably mounted on the inner circle of the first airflow baffle ring.

[0018] Preferably, the inner diameter of the first airflow baffle ring is 120% of the wafer diameter, and the inner diameter of the innermost stacked baffle ring is 80% of the wafer diameter.

[0019] Preferably, the airflow control system also includes: a second airflow baffle ring; the second airflow baffle ring is arranged between the wafer carrier and the reaction chamber, and is located below the first airflow baffle ring, and an annular air passage is formed between the outer circle of the second airflow baffle ring and the reaction chamber.

[0020] Preferably, the second airflow baffle ring is a circular ring coaxial with the wafer carrier, and the inner diameter thereof matches the outer diameter of the wafer carrier.

[0021] Preferably, the airflow control system further comprises: a second lifting device; the second lifting device can make the second airflow blocking ring move up and down.

[0022] Preferably, the second lifting device includes: a second lifting drive and a second transmission mechanism; the second transmission mechanism is located between the wafer carrier and the reaction chamber; and the second lifting drive is arranged outside the reaction chamber.

[0023] Preferably, the second transmission mechanism includes: a second baffle ring lifting rod and a second guide sleeve; the first end of the second baffle ring lifting rod is connected to the second airflow baffle ring, and the second end of the second baffle ring lifting rod is connected to the second lifting drive; the middle part of the second baffle ring lifting rod is arranged in the second guide sleeve, and the second guide sleeve is arranged on the inner surface of the chamber substrate in the reaction chamber and is located between the wafer carrier and the reaction chamber.

[0024] Preferably, the second transmission mechanism also includes: a second adjusting block and a second fixed seat; the first end of the second baffle ring lifting rod is connected to the first end face of the second adjusting block through a second adjusting block screw, the second end face of the second adjusting block is connected to the second airflow baffle ring through a second fixing screw, and the second end of the second baffle ring lifting rod is connected to the second lifting drive through the second fixed seat.

[0025] Preferably, the height difference between the first airflow baffle ring and the second airflow baffle ring is 20-70 mm.

[0026] An etching method, using the above-mentioned etcher with adjustable airflow, comprises the following steps:

[0027] S1, forming a SiO2 insulating layer and an Al layer in sequence on a semiconductor substrate;

[0028] S2. Setting the airflow control system, including: adjusting the diameter of the vent hole;

[0029] S3, etching the Al layer.

[0030] Preferably, the setting of the airflow control system further includes: adjusting the height difference between the first airflow baffle ring and the second airflow baffle ring.

[0031] Preferably, before setting the airflow control system, the method further comprises: obtaining the optimal values ​​of the vent hole diameter and the height difference, comprising the steps of:

[0032] The height difference remains unchanged, the etching rate uniformity under different vent hole diameters is obtained, and the vent hole diameter corresponding to the optimal etching rate uniformity is obtained by comparison;

[0033] The vent hole diameter corresponding to the optimal etching rate uniformity remains unchanged, the etching rate uniformity under different height differences is obtained, and the height difference corresponding to the optimal etching rate uniformity is obtained by comparison.

[0034] Preferably, obtaining the optimal values ​​of the vent hole diameter and the height difference includes:

[0035] The diameter of the vent hole is set to 220 mm, and the etching rate uniformity is obtained when the height difference is 20, 30, 40, and 50 mm, respectively, and the height difference corresponding to the optimal etching rate uniformity is obtained by comparison;

[0036] The height difference is set to 30 mm, and the etching rate uniformity is obtained when the vent hole diameters are 210, 220, and 230 mm, respectively. The vent hole diameters corresponding to the optimal etching rate uniformity are obtained by comparison.

[0037] As can be seen from the above technical solutions, the etcher with adjustable airflow provided by the present invention concentrates the plasma gas by providing a first airflow baffle ring, thereby solving the technical problem of poor uniformity of the etcher.

[0038] The etching machine can also meet the needs of different processes by detachably installing a superimposed baffle ring on the inner circle of the first airflow baffle ring, without having to disassemble and replace the first airflow baffle ring;

[0039] The etcher further improves uniformity by adjusting the height difference between the first airflow baffle ring and the second airflow baffle ring;

[0040] The present invention also provides an etching method. Since the above-mentioned etcher with adjustable airflow is adopted, it also has corresponding beneficial effects. For details, please refer to the above description, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0042] FIG1 is a schematic diagram of the overall structure of an etcher with adjustable gas flow provided by an embodiment of the present invention;

[0043] FIG2 is a schematic structural diagram of a chamber of an etcher with adjustable gas flow provided by an embodiment of the present invention;

[0044] 3 is a schematic diagram of the airflow direction of an etcher with adjustable airflow provided by an embodiment of the present invention;

[0045] FIG4 is a schematic diagram showing a partially enlarged structure of a chamber of an etcher with adjustable gas flow provided by an embodiment of the present invention;

[0046] FIG5 is a schematic diagram of the airflow direction (before flow control) of the prior art;

[0047] FIG6 is a schematic diagram of the airflow direction (after flow control) of the etcher with adjustable airflow provided by an embodiment of the present invention;

[0048] FIG7 is a schematic diagram of a method for improving uniformity of an etcher with adjustable gas flow provided by an embodiment of the present invention;

[0049] FIG8 is a comparison diagram of 8-inch uniformity at different inner diameters with a height difference of 30 mm provided by Example 1 of the present invention;

[0050] FIG9 is a comparison diagram of 8-inch uniformity at different height differences with an inner diameter of 220 mm provided in Example 2 of the present invention;

[0051] FIG10 is a comparison diagram of 6-inch uniformity under different inner diameters with a height difference of 30 mm provided by Example 3 of the present invention.

[0052] Among them, 101-reaction chamber, 102-lower cylinder fixing seat, 103-second lifting drive, 104-second fixing seat, 105-lower cylinder lifting plate fixing screw, 106-second baffle ring lifting rod, 107-second adjustment block, 108-second airflow baffle ring, 109-upper cylinder fixing seat, 110-first lifting drive, 111-first fixing seat, 112-first baffle ring lifting rod, 113-chamber liner, 114-first guide sleeve, 115-second guide sleeve, 116-first adjustment block, 117-first airflow baffle ring, 118-127-superimposed baffle ring, 128-first fixing screw, 129- First adjusting block screw, 130-second adjusting block screw, 131-second fixing screw, 132-electrode insulation seat, 133-electrode cover, 134-electrostatic suction cup, 135-bias electrode, 136-shielding cover, 137-plasma coupling coil, 138-ceramic dielectric window, 139-nozzle, 140-excitation source matching network, 141-excitation source RF power supply, 142-gas source, 143-pressure control valve, 144-vacuum pump, 145-bias matching network, 146-bias RF power supply, 147-chamber cover, 148-wafer focusing ring. DETAILED DESCRIPTION

[0053] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0054] The adjustable airflow etcher provided in an embodiment of the present invention includes: a reaction chamber 101, a nozzle 139, a wafer carrier, and an airflow control system. The structure thereof can be referred to FIG1 . It should be noted that the wafer carrier is located in the middle of the reaction chamber 101 and is used to place the wafer.

[0055] The airflow control system includes: a first airflow baffle ring 117, the structure of which can be referred to Figures 1, 2 and 4;

[0056] The first air flow baffle ring 117 is disposed in the reaction chamber 101 and is located between the nozzle 139 and the wafer stage;

[0057] A vent hole is formed at a position of the first airflow baffle ring 117 opposite to the nozzle 139 .

[0058] The working principle and purpose of the above scheme are as follows:

[0059] In the prior art, the gas ejected from the nozzle has uneven density and distribution in the area above the wafer stage, and diffuses disorderly around the area. The gas flow direction can be seen in FIG5 .

[0060] The present invention provides a first airflow baffle ring 117. Gas is ejected from the nozzle 139 and passes through the vent holes of the first airflow baffle ring 117. The vent holes can gather the airflow toward the center above the wafer and then spray it toward the wafer on the wafer stage. In the present invention, the gas passing through the vent holes has uniform density and distribution and is sprayed toward the wafer in an orderly manner. The airflow direction can be seen in FIG6 .

[0061] As can be seen from the above, the gas is gathered by providing the first gas flow baffle ring 117 , thereby solving the technical problem of poor uniformity of the etcher.

[0062] Specifically, the first airflow baffle ring 117 is a circular ring with an outer diameter that matches the inner diameter of the sidewall of the chamber liner 113 within the reaction chamber 101. Its structure can be seen in Figure 1 . A gap is left between the outer diameter of the first airflow baffle ring 117 and the sidewall of the chamber liner 113 to prevent particle accumulation. This design allows particles to fall under the action of gravity and prevents them from accumulating between the first airflow baffle ring 117 and the sidewall of the chamber liner 113.

[0063] Preferably, the airflow control system further comprises: a first lifting device;

[0064] The first lifting mechanism enables the first airflow baffle ring 117 to move up and down. This design adjusts the height L2 of the first airflow baffle ring 117, i.e., the distance between the first airflow baffle ring 117 and the bottom surface of the chamber liner 113, thereby changing the distance between the nozzle 139 and the wafer (see FIG3 ). This controls the airflow direction and flow rate, thereby adjusting the etching uniformity. It should be noted that the chamber liner 113 includes an axially extending sidewall portion and a radially extending bottom portion.

[0065] In this solution, the first lifting mechanism includes: a first lifting drive 110 and a first transmission mechanism, the structure of which can be referred to Figures 1 and 2;

[0066] The first transmission mechanism is located between the wafer stage and the reaction chamber 101, which can fully utilize the space inside the chamber without affecting the operation of the original structure. In this embodiment, the wafer stage can specifically include an electrode insulation base 132, an electrode cover 133, an electrostatic chuck 134, a bias electrode 135 and a wafer focus ring 148.

[0067] The first lifting drive 110 is disposed outside the reaction chamber 101 . This design can save space in the chamber.

[0068] Furthermore, the first transmission mechanism includes: a first baffle ring lifting rod 112 and a first guide sleeve 114, the structure of which can be referred to Figures 1 and 2;

[0069] The first end of the first baffle ring lifting rod 112 is connected to the first airflow baffle ring 117, and the second end of the first baffle ring lifting rod 112 is connected to the first lifting drive 110. In this design, the first lifting drive 110 drives the first airflow baffle ring 117 to move up and down through the first baffle ring lifting rod 112;

[0070] The middle portion of the first retaining ring lifting rod 112 is disposed in a first guide sleeve 114. The first guide sleeve 114 is disposed on the bottom surface of a chamber liner 113 disposed in the reaction chamber 101 and is located between the wafer stage and the reaction chamber 101. It should be noted that the first guide sleeve 114 serves a guiding function.

[0071] Specifically, the first transmission mechanism further includes: a first adjustment block 116 and a first fixing seat 111, the structure of which can be referred to Figures 1 and 2;

[0072] The first end of the first baffle ring lifting rod 112 is connected to the first end face of the first adjustment block 116 via a first adjustment block screw 129. The second end face of the first adjustment block 116 is connected to the first airflow baffle ring 117 via a first fixing screw 128. The second end of the first baffle ring rod 112 is connected to the first lifting drive 110 via a first fixing seat 111. It should be noted that the first adjustment block 116 serves as an adjustment support; it should also be noted that the first fixing seat 111 serves as a fixing support.

[0073] Preferably, the airflow control system also includes: a superimposed baffle ring, the specific structure of which can be referred to Figures 2 and 4. The outer circle of the superimposed baffle ring can be detachably installed on the inner circle of the first airflow baffle ring 117. It should be noted that through this design, different superimposed baffle rings can be replaced according to process requirements without the need to disassemble and replace the first airflow baffle ring 117, which is convenient and quick; it should also be noted that the inner circle of the first airflow baffle ring 117 is the aforementioned vent, which is coaxial with the nozzle 139.

[0074] In this solution, the number of stacked baffle rings is multiple, and the specific structure can be referred to Figures 2 and 4. The outer circle of the inner stacked baffle ring can be removably installed on the inner circle of the outer stacked baffle ring, and the outer circle of the outermost stacked baffle ring can be removably installed on the inner circle of the first airflow baffle ring 117. By designing and arranging multiple baffle rings with different inner diameters in a stacked manner to meet different process requirements, the assembly can be achieved by overlapping the inner and outer circles into a conical structure with a larger upper part and a smaller lower part.

[0075] Furthermore, the inner diameter of the first airflow baffle ring 117 is 120% of the wafer diameter, and the inner diameter of the innermost overlapping baffle ring is 80% of the wafer diameter. It should be noted that the diameter of the first airflow baffle ring 117 (wafer size ± 20%), for example, if the diameter of an 8-inch wafer is 200 mm, the diameter of the first airflow baffle ring 117 ranges from 160 to 240 mm.

[0076] Specifically, the airflow control system further includes: a second airflow baffle ring 108, the structure of which can be referred to Figures 1 and 2,

[0077] The second airflow baffle ring 108 is disposed between the wafer stage and the reaction chamber 101, and is located below the first airflow baffle ring 117. An annular air passage is formed between the outer diameter of the second airflow baffle ring 108 and the reaction chamber 101. It should be noted that the second airflow baffle ring 108 cooperates with the first airflow baffle ring 117 to control the velocity of the fluid and thereby adjust its uniformity (see FIG7 ). It should also be noted that an annular air passage can be formed by setting the outer diameter of the second airflow baffle ring 108 to be smaller than the inner diameter of the reaction chamber 101.

[0078] Preferably, second airflow baffle ring 108 is a circular ring coaxial with the wafer stage, with an inner diameter matching the outer diameter of the wafer stage. Its structure can be seen in Figure 4 . It should be noted that second airflow baffle ring 108 and the wafer stage have a clearance fit. Furthermore, this design increases the fluid retention area, thereby adjusting uniformity (see Figure 7 ).

[0079] In this solution, the airflow control system further comprises: a second lifting device;

[0080] The second lifting device can make the second airflow baffle ring 108 move up and down. This design changes the distance L3 between the second airflow baffle ring 108 and the first airflow baffle ring 117 by adjusting the height L1 of the second airflow baffle ring 108, that is, the distance between the second airflow baffle ring 108 and the bottom surface of the chamber liner 113 (refer to Figure 3), thereby controlling the airflow direction and flow rate, and then adjusting the uniformity of etching.

[0081] Furthermore, the second lifting device includes: a second lifting drive 103 and a second transmission mechanism, the structure of which can be referred to Figures 1 and 2;

[0082] The second transmission mechanism is located between the wafer stage and the reaction chamber 101, which can fully utilize the space inside the chamber without affecting the operation of the original structure;

[0083] The second lifting drive 103 is disposed outside the reaction chamber 101 . This design can save space in the chamber.

[0084] Furthermore, the second transmission mechanism includes: a second baffle ring lifting rod 106 and a second guide sleeve 115, the structure of which can be referred to Figures 1 and 2;

[0085] The first end of the second baffle ring lifting rod 106 is connected to the second airflow baffle ring 108, and the second end of the second baffle ring lifting rod 106 is connected to the second lifting drive 103. In this design, the second lifting drive 103 drives the second airflow baffle ring 108 to move up and down through the second baffle ring lifting rod 106;

[0086] The middle portion of the second retaining ring lifting rod 106 is disposed in a second guide sleeve 115. The second guide sleeve 115 is disposed on the bottom surface of a chamber liner 113 disposed in the reaction chamber 101 and is located between the wafer stage and the reaction chamber 101. It should be noted that the second guide sleeve 115 serves a guiding function.

[0087] Specifically, the second transmission mechanism further includes: a second adjustment block 107 and a second fixing seat 104, the structure of which can be referred to Figures 1 and 2;

[0088] The first end of the second baffle ring lifting rod 106 is connected to the first end surface of the second adjustment block 107 via a second adjustment block screw 130. The second end surface of the second adjustment block 107 is connected to the second airflow baffle ring 108 via a second fixing screw 131. The second end of the second baffle ring lifting rod 106 is connected to the second lifting drive 103 via a second fixing base 104. It should be noted that the second adjustment block 107 serves as an adjustment support; it should also be noted that the second fixing base 104 serves as a fixing support.

[0089] Alternatively, the height difference between the first airflow baffle ring 117 and the second airflow baffle ring 108 is 20-70 mm. The height difference between the first airflow baffle ring 117 and the second airflow baffle ring 108 is L3 (see FIG. 2 ). Different values ​​of L3 determine different flow rates of the airflow.

[0090] An embodiment of the present invention further provides an etching method, using the above-mentioned etcher with adjustable gas flow, comprising the steps of:

[0091] S1, forming a SiO2 insulating layer and an Al layer in sequence on a semiconductor substrate;

[0092] S2. Set up the airflow control system, including: adjusting the diameter of the vent holes:

[0093] S3. Etching the Al layer.

[0094] Furthermore, setting up an airflow control system also includes: adjusting the height difference between the first airflow baffle ring 117 and the second airflow baffle ring 108, namely the aforementioned L3 (refer to Figure 3), so as to control the airflow direction and flow rate, and further adjust the uniformity of etching.

[0095] Specifically, before setting the airflow control system, the method further includes: obtaining optimal values ​​of the vent hole diameter and height difference, including the steps of:

[0096] The height difference remains unchanged, and the etching rate uniformity under different vent hole diameters is obtained, and the vent hole diameter corresponding to the optimal etching rate uniformity is obtained by comparison;

[0097] The diameter of the vent hole remains unchanged, and the etching rate uniformity under different height differences is obtained. The height difference corresponding to the optimal etching rate uniformity is compared.

[0098] Preferably, obtaining the optimal values ​​of the vent hole diameter and height difference includes:

[0099] The diameter of the vent hole is set to 220 mm, and the etching rate uniformity is obtained at height differences of 20, 30, 40 and 50 mm, respectively. The height differences corresponding to the optimal etching rate uniformity are compared. In this solution, the diameter of the vent hole is adjusted to 220 mm, and the height difference L3 between the first airflow baffle ring 117 and the second airflow baffle ring 108 is adjusted to 20, 30, 40 and 50 mm, respectively (refer to Figure 3). Under different height differences, the etching rate uniformity is recorded. It is found that when the height difference is 30 mm, the uniformity of the 8-inch aluminum wafer can reach 3.1%, which can be referred to Figure 9.

[0100] The height difference is set to 30 mm, and the etching rate uniformity is obtained when the vent diameters are 210, 220 and 230 mm respectively. The vent diameters corresponding to the optimal etching rate uniformity are compared. In this solution, the height difference L3 between the first airflow baffle ring 117 and the second airflow baffle ring 108 is adjusted to 30 mm, and the vent diameters are adjusted to 210, 220 and 230 mm respectively (refer to Figures 2 and 3). Under different diameters, the etching rate uniformity is recorded. It is found that when the diameter is 220 mm, the uniformity of an 8-inch aluminum wafer can reach 3.1%. Please refer to Figure 8.

[0101] The present invention will be further described below with reference to specific embodiments:

[0102] As shown in Figures 1 and 2, the main components of the etching chamber of the plasma etcher of the present invention are: a reaction chamber 101, a chamber liner 113, a plasma coupling coil 137, a chamber cover 147, a ceramic dielectric window 138, an excitation source RF power supply 141, an excitation source matching network 140, a shielding cover 136, a gas source 142, a nozzle 139, a bias RF power supply 146, a bias matching network 145, a pressure control valve 143, a vacuum pump 144, an electrode cover 133, a wafer focusing ring 148, a first airflow baffle ring 117, a first guide sleeve 114, a first baffle ring lifting rod 112, a first It consists of a lifting drive 110, a first fixed seat 111, a second airflow baffle ring 108, a second guide sleeve 115, a second baffle ring lifting rod 106, a second lifting drive 103, a second adjusting block screw 130, an electrode insulating seat 132, a lower cylinder fixed seat 102, a lower cylinder lifting plate fixing screw 105, an upper cylinder fixed seat 109, a bias electrode 135, an electrostatic suction cup 134, a first adjusting block screw 129, a first adjusting block 116, a first fixing screw 128, a second fixing screw 131, a second adjusting block 107, a second fixed seat 104 and multiple sets of stacked baffle rings 118~127.

[0103] As described above, in the adjustable airflow combined baffle ring structure of the present invention, the first airflow baffle ring 117 and the second airflow baffle ring 108 can be raised and lowered respectively by the first lifting drive 110 and 103. A distance is left between the outer circle of the first airflow baffle ring 117 and the chamber liner 113 to prevent particle accumulation.

[0104] As shown in Figures 2 and 3, the present invention describes an adjustable airflow combined baffle ring structure. A gas source 142 provides process gas that is sprayed into the reaction chamber 101 through a nozzle 139. Plasma is generated under the action of a plasma coupling coil 137. The bias electrode 135 provides a bias voltage to accelerate the plasma and bombard the wafer above the electrostatic chuck 134. The first airflow baffle ring 117 can focus the airflow toward the center above the wafer, allowing it to react more directly with the wafer. The second airflow baffle ring 108 is combined with the electrostatic chuck 134 and the electrode cover 133 to increase the gas retention area, making it less likely that the gas will be directly extracted, thereby increasing the reaction time between the gas and the wafer. The first airflow baffle ring 117 and the second airflow baffle ring 108 together form a system for controlling airflow.

[0105] As shown in Figures 2 and 3, the second airflow baffle ring 108 can be raised and lowered, denoted by the variable height L1. The first airflow baffle ring 117 can also be raised and lowered, denoted by the variable height L2. By adjusting the heights L1 and L2, different height combinations can be achieved. The gap between the first and second airflow baffle rings 117 and 108 can also be adjusted to different values, namely, L3. By adjusting the heights L2 of the first and second airflow baffle rings 117 and 108, as well as the height distance L3 between the first and second airflow baffle rings 117 and 108, different airflow directions and velocities can be achieved. The heights L1 and L2 determine the airflow direction, while the value of L3 determines the airflow velocity. Thus, etching uniformity can be adjusted by adjusting the airflow direction and velocity. For different etching processes, simply raising and lowering the first and second airflow baffle rings 117 and 108 to achieve different combinations of L1, L2, and L3 can satisfy the uniformity requirements for each process.

[0106] As shown in Figures 2, 3, and 4, uniformity adjustment in different etching processes also requires different inner diameters for the first airflow baffle ring 117. Multiple baffle rings with different inner diameters are stacked to meet these diverse process requirements. Specifically, removable and stackable baffle rings 118 to 127 are incorporated into the first airflow baffle ring 117 to achieve different combined inner diameters, or D values, to meet the requirements of different processes. This eliminates the need to disassemble and replace the first airflow baffle ring 117, making it convenient and quick.

[0107] The above-mentioned adjustable airflow combined baffle ring structure:

[0108] The first airflow baffle ring 117 and the second airflow baffle ring 108 can be raised and lowered to different heights and distances to adjust etching uniformity for different processes. Overlay baffle rings 118-127 of varying inner diameters can be placed on the first airflow baffle ring 117 to focus the airflow to varying degrees, further adjusting etching uniformity for different processes.

[0109] In summary, the adjustable airflow combined baffle ring structure of the present invention can adjust the flow direction and flow rate of the airflow in the etching chamber of the plasma etcher, thereby improving the etching uniformity.

[0110] FIG3 is a schematic diagram of the main airflow direction in the chamber, FIG6 is a schematic diagram of the fluid direction after flow control according to the present invention, and FIG7 is a schematic diagram of the method for improving uniformity according to the present invention.

[0111] Key points of the invention: The plasma concentration in the etcher chamber is adjusted by an airflow control system; the etcher realizes the lifting and lowering of the airflow baffle ring by setting a lifting device; the etcher adjusts the uniformity of etching by adjusting the airflow direction and airflow velocity.

[0112] Methods

[0113] In order to solve the problem of etching uniformity of a plasma etcher, the present invention proposes a method for optimizing etching uniformity by using a combined baffle ring structure.

[0114] This patent discloses a method for optimizing etching uniformity using a combined baffle ring structure. The specific steps are: first, assemble the above-mentioned combined baffle ring structure device in the etching chamber, and then use chlorine-based gas, bromine-based gas, fluorine-based gas or a combination of them to etch the wafer. It is characterized in that better etching uniformity is achieved by adjusting the height difference between the first airflow baffle ring 117 and the second airflow baffle ring 108 and the inner diameter of the first airflow baffle ring 117 and the process parameters.

[0115] A device for optimizing etching uniformity using a combined baffle ring, wherein the height difference between the upper and lower ascending and descending airflow baffle rings can be adjusted within a range of 20-70 mm.

[0116] A device for optimizing etching uniformity using a combined baffle ring, wherein the inner diameter of the first airflow baffle ring 117 can be adjusted within a range of 150-240 mm.

[0117] A method for optimizing etching uniformity by using a combined baffle ring, wherein the etching method adopted is a plasma etching method.

[0118] A method for optimizing etching uniformity using a combined baffle ring can be used to improve the uniformity of Al, AlN, AlScN, Mo or W processes.

[0119] A method for optimizing etching uniformity by using a combined baffle ring, wherein the etching gas is a chlorine-based gas, a bromine-based gas, a fluorine-based gas or a combination thereof.

[0120] The RF power range of the ICP machine used in the dry etching method is 0-1000W.

[0121] The RF power range of the ICP machine used in the dry etching method is 0-800W.

[0122] The dry etching method uses a chamber pressure of 2-50 mTorr and a total flow rate of 50-250 sccm.

[0123] The dry etching method requires the chiller temperature of the ICP etcher to be 0-50°C.

[0124] Example 1: This example demonstrates the process of optimizing wafer etching uniformity using this etching method.

[0125] Step 1: forming a SiO2 insulating layer and an Al layer in sequence on a semiconductor substrate;

[0126] Step 2: Install a combined baffle ring structure device on the ICP chamber, adjust the height difference between the first airflow baffle ring 117 and the second airflow baffle ring 108 to 30 mm, and adjust the inner diameter of the first airflow baffle ring 117 to 210, 220 and 230 mm, which can optimize the uniformity of the 8-inch aluminum wafer to 3.1%.

[0127] Step 3: Etch the Al layer using an ICP etcher. The ICP etcher parameters were set as follows: upper RF power 1000W, lower RF power 150W, ICP etcher chiller temperature 35°C, chamber pressure 10mTorr, and gases 30sccmBCl3 and 120sccmCl2. The etched volume was half the film thickness. Etch rate uniformity, as shown in Figure 8, can be optimized to 3.1% uniformity on an 8-inch aluminum wafer (using the 49-point range method).

[0128] Example 2: This example demonstrates the process of optimizing wafer etching uniformity using this etching method.

[0129] Step 1: forming a SiO2 insulating layer and an Al layer in sequence on a semiconductor substrate;

[0130] Step 2: Install a combined baffle ring structure device on the ICP chamber, adjust the height difference between the first airflow baffle ring 117 and the second airflow baffle ring 108 to 20, 30, 40 and 50 mm, and the inner diameter of the first airflow baffle ring 117 is 220 mm;

[0131] Step 3: Etch the Al layer using an ICP etcher. The ICP etcher parameters were set as follows: upper RF power 1000W, lower RF power 150W, ICP etcher chiller temperature 35°C, chamber pressure 10mTorr, and gases 30sccmBCl3 and 120sccmCl2. The etched volume was half the film thickness. Etch rate uniformity, as shown in Figure 9, can be optimized to 3.1% uniformity on an 8-inch aluminum wafer (49-point range method).

[0132] Example 3: This example demonstrates the process of optimizing wafer etching uniformity using this etching method.

[0133] Step 1: forming a SiO2 insulating layer and an Al layer in sequence on a semiconductor substrate;

[0134] Step 2: Install a combined baffle ring structure device on the ICP chamber, adjust the height difference between the first airflow baffle ring 117 and the second airflow baffle ring 108 to 30 mm, and adjust the inner diameter of the first airflow baffle ring 117 to 220, 170, 160 and 150 mm, which can optimize the uniformity of 6-inch aluminum wafers to 3.5%.

[0135] Step 3: Etch the Al layer using an ICP etcher. The ICP etcher parameters were set as follows: upper RF power 1000W, lower RF power 150W, ICP etcher chiller temperature 35°C, chamber pressure 10mTorr, and gases 30sccmBCl3 and 120sccmCl2. The etch volume was half the film thickness. Etch rate uniformity, as shown in Figure 10, can be optimized to 3.5% uniformity on a 6-inch aluminum wafer (49-point range method).

[0136] Key points of the invention: The etcher realizes the lifting and lowering of the airflow baffle ring by setting a lifting device; the etcher achieves the uniformity of the aluminum wafer by adjusting the airflow direction and airflow velocity; the etcher etches the Al layer.

[0137] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0138] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An etcher with adjustable gas flow, characterized in that: include: A reaction chamber (101), a nozzle (139), a wafer carrier and an air flow control system; The airflow control system comprises: a first airflow baffle ring (117); The first airflow baffle ring (117) is arranged in the reaction chamber (101) and is located between the nozzle (139) and the wafer carrier; A vent hole is provided at a position of the first airflow baffle ring (117) opposite to the nozzle (139).

2. The etcher with adjustable gas flow according to claim 1, characterized in that: The first airflow baffle ring (117) is a circular ring, the outer diameter of which matches the inner diameter of the side wall of the chamber liner (113) in the reaction chamber (101), and a gap is left between the outer circle of the first airflow baffle ring (117) and the side wall of the chamber liner (113) to prevent particle aggregation.

3. The etcher with adjustable gas flow according to claim 1, characterized in that: The airflow control system further comprises: a first lifting device; The first lifting device can enable the first airflow blocking ring (117) to move up and down.

4. The etcher with adjustable gas flow according to claim 3, characterized in that: The first lifting mechanism comprises: a first lifting drive (110) and a first transmission mechanism; The first transmission mechanism is located between the wafer carrier and the reaction chamber (101); The first lifting drive (110) is arranged outside the reaction chamber (101).

5. The etcher with adjustable gas flow according to claim 4, characterized in that: The first transmission mechanism comprises: a first baffle ring lifting rod (112) and a first guide sleeve (114); The first end of the first baffle ring lifting rod (112) is connected to the first airflow baffle ring (117), and the second end of the first baffle ring lifting rod (112) is connected to the first lifting drive (110); The middle portion of the first retaining ring lifting rod (112) is arranged in the first guide sleeve (114), and the first guide sleeve (114) is arranged on the bottom surface of the chamber liner (113) in the reaction chamber (101) and is located between the wafer carrier and the reaction chamber (101).

6. The etcher with adjustable gas flow according to claim 5, characterized in that: The first transmission mechanism further comprises: a first adjustment block (116) and a first fixing seat (111); The first end of the first baffle ring lifting rod (112) is connected to the The first end face of the first adjusting block (116) and the second end face of the first adjusting block (116) are connected to the first airflow baffle ring (117) via a first fixing screw (128), and the second end of the first baffle ring rod (112) is connected to the first lifting drive (110) via the first fixing seat (111).

7. The etcher with adjustable gas flow according to claim 1, characterized in that: The airflow control system further comprises: a stacked baffle ring; the outer circle of the stacked baffle ring can be detachably mounted on the inner circle of the first airflow baffle ring (117).

8. The etcher with adjustable gas flow according to claim 7, characterized in that: The number of the stacked baffle rings is multiple, with inner and outer arrangements. The outer circle of the inner stacked baffle ring can be detachably mounted on the inner circle of the outer stacked baffle ring, and the outer circle of the outermost stacked baffle ring can be detachably mounted on the inner circle of the first airflow baffle ring (117).

9. The etcher with adjustable gas flow according to claim 8, characterized in that: The inner diameter of the first airflow baffle ring (117) is 120% of the diameter of the wafer, and the inner diameter of the innermost stacked baffle ring is 80% of the diameter of the wafer.

10. The etcher with adjustable gas flow according to any one of claims 1 to 9, characterized in that: The airflow control system further comprises: a second airflow baffle ring (108); The second airflow baffle ring (108) is arranged between the wafer carrier and the reaction chamber (101), and is located below the first airflow baffle ring (117), and an annular air passage is formed between the outer circle of the second airflow baffle ring (108) and the reaction chamber (101).

11. The etcher with adjustable gas flow according to claim 10, characterized in that: The second airflow baffle ring (108) is a circular ring coaxial with the wafer carrier, and its inner diameter matches the outer diameter of the wafer carrier.

12. The etcher with adjustable gas flow according to claim 10, characterized in that: The airflow control system further includes: a second lifting device; The second lifting device can enable the second airflow blocking ring (108) to move up and down.

13. The etcher with adjustable gas flow according to claim 12, characterized in that: The second lifting device comprises: a second lifting drive (103) and a second transmission mechanism; The second transmission mechanism is located between the wafer carrier and the reaction chamber (101); The second lifting drive (103) is arranged outside the reaction chamber (101).

14. The etcher with adjustable gas flow according to claim 13, characterized in that: The second transmission mechanism comprises: a second baffle ring lifting rod (106) and a second guide sleeve (115); The first end of the second baffle ring lifting rod (106) is connected to the second airflow baffle ring (108), and the second end of the second baffle ring lifting rod (106) is connected to the second lifting drive (103); The middle part of the second retaining ring lifting rod (106) is arranged in the second guide sleeve (115), and the second guide sleeve (115) is arranged on the bottom surface of the chamber liner (113) in the reaction chamber (101) and is located between the wafer carrier and the reaction chamber (101).

15. The etcher with adjustable gas flow according to claim 14, characterized in that: The second transmission mechanism further comprises: a second adjustment block (107) and a second fixing seat (104); The first end of the second baffle ring lifting rod (106) is connected to the first end face of the second adjustment block (107) via a second adjustment block screw (130), the second end face of the second adjustment block (107) is connected to the second airflow baffle ring (108) via a second fixing screw (131), and the second end of the second baffle ring lifting rod (106) is connected to the second lifting drive (103) via the second fixing seat (104).

16. The etcher with adjustable gas flow according to claim 10, characterized in that: The height difference between the first airflow baffle ring (117) and the second airflow baffle ring (108) is 20-70 mm.

17. An etching method, characterized in that: An etcher using the adjustable gas flow as claimed in claims 1 to 16, comprising the steps of: S1, sequentially forming a SiO2 insulating layer and an Al layer on a semiconductor substrate; S2, setting the airflow control system, including: adjusting the diameter of the vent hole; S3, etching the Al layer.

18. The etching method according to claim 17, characterized in that: The setting of the airflow control system further includes: adjusting the height difference between the first airflow baffle ring (117) and the second airflow baffle ring (108).

19. The etching method according to claim 18, characterized in that: Before setting the airflow control system, the method further includes: obtaining the optimal values ​​of the vent hole diameter and the height difference, including the steps of: The height difference remains unchanged, the etching rate uniformity under different vent hole diameters is obtained, and the vent hole diameter corresponding to the optimal etching rate uniformity is obtained by comparison; The diameter of the vent hole remains unchanged, and the uniformity of the etching rate under different height differences is obtained, and the height difference corresponding to the optimal uniformity of the etching rate is obtained by comparison.

20. The etching method according to claim 19, characterized in that: The obtaining of the optimal values ​​of the vent hole diameter and the height difference comprises: The diameter of the vent hole is set to 220 mm, and the uniformity of the etching rate when the height difference is 20, 30, 40 and 50 mm is obtained, and the height difference corresponding to the optimal uniformity of the etching rate is obtained by comparison; The height difference is set to 30 mm, and the etching rate uniformity is obtained when the vent hole diameters are 210, 220 and 230 mm respectively, and the vent hole diameters corresponding to the optimal etching rate uniformity are obtained by comparison.

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