The present disclosure relates to processes used to fabricate semiconductor devices, and more specifically to an apparatus used to remove particles equipped in a semiconductor fabrication tool.
The fabrication of semiconductor devices includes hundreds of individual steps performed on a wafer. For example, the steps of this process can include oxidation, diffusion, ion implantation, thin film deposition, cleaning, etching and lithography. Processing chambers for such steps have been designed as multiple processing stations or modules, wherein the processing chambers are arranged in a radial arrangement around a central handling mechanism and are designed to perform a certain type of processing operation.
However, a yield of semiconductor devices can be adversely influenced by the patterning procedure, such as photolithography and a dry etching, due to the presence of unwanted particles present in the processing chambers. The particles in the processing chambers, formed from previous dry etching procedures or depositions, can settle on an exposed region of metal layers or exposed photoresist layers. The particles mask the exposed region during a dry etching procedure, resulting in damages on a predetermined pattern and leading to an unwanted pattern. Thus, removing the particles is of great importance for the fabrication of semiconductor devices.
Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is noted that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.
The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
Further, spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.
The terms “wafer” and “substrate,” as used herein, are to be understood as including silicon, silicon-on-insulator (SOI) technology, silicon-on-sapphire (SOS) technology, doped and undoped semiconductors, epitaxial layers of silicon supported by a base semiconductor foundation, and other semiconductor structures. Furthermore, when reference is made to a “wafer” or “substrate” in the following description, previous processing steps may have been utilized to form regions, junctions, or material layers in or over the base semiconductor structure or foundation. In addition, the semiconductor does not need to be silicon-based, but could be based on silicon-germanium, germanium, gallium arsenide or other semiconductor structures.
The terms “deposition” and “deposit,” as used herein, refer to operations of depositing materials on a substrate using a vapor phase of a material to be deposited, a precursor of the material, and an electrochemical reaction or sputtering/reactive sputtering. Depositions using a vapor phase of a material include any operations such as, but not limited to, chemical vapor deposition (CVD) and physical vapor deposition (PVD). Examples of vapor deposition methods include hot filament CVD, rf-CVD, laser CVD (LCVD), conformal diamond coating operations, metal-organic CVD (MOCVD), thermal evaporation PVD, ionized metal PVD (IMPVD), electron beam PVD (EBPVD), reactive PVD, atomic layer deposition (ALD), plasma enhanced CVD (PECVD), high density plasma CVD (HDPCVD), low pressure CVD (LPCVD), and the like. Examples of deposition using an electrochemical reaction include electroplating, electro-less plating, and the like. Other examples of deposition include pulse laser deposition (PLD) and atomic layer deposition (ALD).
The fabrication of microelectronic devices involves a complicated process sequence including hundreds of process steps performed on semiconductor substrates. For example, such process steps include cleaning, oxidation, diffusion, ion implantation, thin film deposition, etching and lithography. By using lithography and etching processes, a predetermined pattern is transferred to a material layer or a substrate. In the lithography step, a blanket photoresist layer is exposed to a radiation source through a reticle or photomask containing a pattern so that an image of the pattern is formed in the photoresist layer. By developing the photoresist layer in a suitable chemical solution, portions of the photoresist layer are removed, thus resulting in a patterned photoresist layer. Later, subsequent etching processes are performed to etch portions of an underlying material layer uncovered by the patterned photoresist layer. With the patterned photoresist layer acting as a mask, the uncovered portions of the underlying material layer are exposed to a reactive environment, e.g., using a wet or dry etching, which results in the pattern being transferred to the underlying material layer. The lithography and etching processes are essential steps to determine scales of the microelectronic devices.
The results of the lithography and etching processes affect a product yield of the microelectronic devices. Defects are very important indicators that affect the product yield rate. The product yield of microelectronic devices can be adversely influenced by the lithography and etching processes, due to the presence of unwanted particles present in the manufacturing chamber. It is found that particles attached on a wafer cause serious defects during a lithography or etching process. The particles may appear during transport or after any function process. When the particles fall on a front side of the wafer, devices or interconnects under the particles will become defective after the etching process. The particles may shield the patterned photoresist layer and hinder the etching gas from reacting with the underlying material layer, thus resulting in a partial etching after the etching process. When the particles attach or settle on a back side of the wafer or an electrostatic chuck (ESC), it will trigger a back side helium alarm. Specifically, the particles may settle on the electrostatic chuck (ESC) or a back side of the wafer. This in turn results in a poor contact between the wafer and the ESC. Since the wafer cannot sit flush on the ESC, this allows helium to leak from the poor contact position or a gap between the wafer and the ESC, resulting in the monitoring of helium in the dry etch chamber, and permits particle contamination in the dry etching tool. If the helium alarm is triggered, the manufacturing process shall be shut down. The manufacturing chambers or the wafer shall be cleaned and reloaded. Concerning the particle issues, an atmosphere transfer module (ATM) or a vacuum transfer module (VTM) Robot station has no devices for removing particles. The wafers can become subjected to particle contamination as a result of the above-mentioned conditions during transportation or any manufacturing process. In order to solve the problem of the particles in a manufacturing process, the present disclosure provides a structure of a particle remover and a configuration of the particle remover equipped in a factory interface or a manufacturing chamber.
In reference to the figures,
The factory interface 103 is configured to load and transfer wafers to a manufacturing chamber. The factory interface 103 is also configured to couple with a manufacturing chamber, for example, load lock chamber 105. The factory interface 103 includes a robot 205, an orienter 130, a housing 110 and a load port 150. The housing 110 is designed to operate in a first environment; for example, the housing 110 is filled with a non-active gas such as nitrogen or argon. In an embodiment, the housing 110 is kept at room temperature and a room pressure, which refers to an atmosphere transfer module (ATM). Do note that the first environment of the housing 110 has many possible variations and options.
A wafer or a cassette of wafers is introduced into the housing 110 through the load port 150, which is often referred to as a load-station for loading and unloading the wafers. For loading wafers, a cassette is put in the load port 150 by a machine (not shown) or a human. At this moment, the load port 150 is temporally in an atmosphere environment. A valve (not shown) between the housing 110 and the load port 150 is closed. As the load port 150 is turned to the first environment, the valve is opened and allows the robot 205 to pass through. A wafer is handled by the robot 205 and transferred to the housing 110.
The robot 205, equipped within the housing 110, transfers the wafer from the load port 150 to an orienter 130. The robot 205 is movable/controllable in at least three-axes or rotatable at any angles. The robot 205 is a single-blade robot, which has a robot blade 206 attached to a robot arm 208. The robot blade 206 is adapted for handling and transferring a wafer to and from various positions.
An orienter 130 is located adjacent to the robot 205 so that the robot 205 is able to transfer wafers to the orienter 130. Later, the wafer is transferred to an orienter 130 by the robot 205 shown as an arrow 30. The orienter 130 is configured to adjust the wafer to a correct orientation for the next manufacturing process. The orienter 130 is able to rotate the wafer and adjust an orientation of the wafer so as to allow an incident optical beam to be directed to a test pattern or a dock on the wafer and return the optical beam in order to be detected by the orienter 130. With the orienter 130, the wafer is precisely positioned and ready to etch or deposit.
The wafer is then transferred from the orienter 130 to load lock chamber 105 by the robot 205 shown as an arrow 32. A valve 61 between the housing 110 and the load lock chamber 105 is opened and allows the robot 205 to pass through and place the wafer in position. When the valve 61 is closed, the load lock chamber 105 is vacuumed to a second environment; for example, the load lock chamber 105 is maintained at a low pressure such as about 200 m-torrs. Other pressures may also be used, for example, less than about 1 torr, with a lower pressure limit of about 10 m-torrs, as determined by the type of vacuum pump used for evacuation of the load lock chamber 105.
Prior to vacuuming the load lock chamber 105, the buffer chamber 300 is already maintained as the second environment so that environments of the load lock chamber 105 and the buffer chamber 300 are substantially equal. The buffer chamber 300 is usually kept in a vacuum environment so as to avoid particle contamination. After the load lock chamber 105 is vacuumed to the second environment, a valve 63 between the load lock chamber 105 and the buffer chamber 300 is opened. The wafer is then handled by a robot 305 and transferred from the load lock chamber 105 to the buffer chamber 300 shown as an arrow 34. The robot 305 is similar to the robot 205 and is also configured to transfer a wafer to a manufacturing chamber. The robot 305 includes a robot arm 306 and a robot blade 308. In an embodiment, the robot arm 306 is equipped as dual-arms or a single arm. Further, the buffer chamber 300 is coupled with a plasma process chamber 310, a deposition chamber 320 and a diffusion chamber 330. The plasma process chamber 310 is able to operate a dry etching process including, for example, a reactive ion etching process. The plasma process chamber 310 provides reactive ion gas so as to react with material layers or the wafer. The deposition chamber 320 provides a vapor phase of a material including any operations such as, but not limited to, chemical vapor deposition (CVD) and physical vapor deposition (PVD). A material layer can be deposited on the wafer in the deposition chamber 320. The diffusion chamber 330 provides a thermal process such as a rapid thermal annealing or a laser annealing. A deposited layer can be annealed in the diffusion chamber 330. The wafer is then transferred from the buffer chamber 300 to the plasma process chamber 310 shown as an arrow 35. After an etching process in the plasma process chamber 310, the wafer is returned to the buffer chamber 300. Later, the wafer is transferred from the buffer chamber 300 to the deposition chamber 320 shown as an arrow 36. After the deposition is accomplished, the wafer is returned to the buffer chamber 300. The wafer is soon sent to the diffusion chamber 330 for annealing shown as an arrow 37. According to the present disclosure, chambers 310, 320 and 330 can also be configured to other different process.
In order to deal with the particle issues, particle removers are equipped in the multi-chamber system 100. In reference to the figures,
In an embodiment, the factory interface 203 further includes a particle remover 72 around valve 61, which is located between load lock chamber 105 and the housing 110 of the factory interface 203. The particle remover 72 has a length of gas outlets that are longer than or equal to that of the valve 61. A structure of the particle remover 72 is the same as the particle remover 71. In an embodiment, another particle remover is located below and vertically aligned with the particle remover 72 around the valve 61, wherein the two particle removers are arranged in a face-to-face manner and toward wafers. The two particle removers are placed apart at a distance and allow the robot 205 to pass through so that two sides of the wafers are both cleaned and gas showered by the particle remover 72 and another particle remover. Therefore, the wafers before manufacturing processes are gas showered and cleaned by the particle remover 72. The particles are blocked and drawn out at the valve 61 so that the manufacturing chambers are kept clean.
The multi-chamber system 200 further includes a control unit 235 configured to communicate with the factory interface 203 or the buffer chamber 300 to allow various operations to be performed in a coordinated fashion. The control unit 235 includes a central processing unit (CPU), a memory, and a support circuit (not shown). The CPU is a general purpose computer processor used in an industrial setting. The CPU receives signals from end terminals and calculates the signals so as to send demands back to the end terminals for operations. The support circuit is coupled to the CPU and may include cache, clock circuits, input/output subsystems, power supplies, and the like. For example, the control unit 235 is able to manipulate movements of the robot 205. In addition, the particle removers (71, 72) are associated with the robot 205 through the control unit 235, wherein the particle removers (71, 72) are configured to manipulate a speed of the robot 205, a flow rate measured at the gas inlets and a flow rate measured at the gas outlets. In operation, the particle removers (71, 72) collect particles and analyze the quantity and sizes of particles entering the gas inlets. The information of the particles is transmitted to the control unit 235 so that the control unit 235 will judge the particle contamination of wafers and determine a speed of the robot 205, a flow rate measured at the gas inlet, and a flow rate measured at the gas outlet according to the quantity and sizes of the particles. If there are amounts of particles detected by the particle removers (71, 72), the control unit 235 will slow down the speed of the robot 205 during the removal of the particles so as to make a complete cleaning of the particles. If the speed of the robot 205 is slow when the particle removers (71, 72) are blowing, the wafers are comprehensively gas showered so that the cleaning effect or efficiency of the particles is enhanced. In some embodiments, if large amounts of particles are detected, a flow rate of the gas outlets are increased so as to enhance the quantity and strength of the ionized gas blowing on the wafers. Meanwhile, a flow rate of the gas inlets is also adjusted so as to remove more particles.
Based on the multi-chamber system 200,
In another example, particle removers are equipped adjacent to manufacturing chambers. In reference to the figures,
Based on the multi-chamber system 400, a possible process flow can be generalized as a flow chart.
Based on the multi-chamber system 400, another possible process flow can be generalized as a flow chart. After the etching process, the wafer continues to be deposited or diffused.
In some embodiments, the particle removers (71, 72, 73, 74, and 76) are respectively and vertically aligned with another particle remover as shown in
To clarify a configuration of gas inlets and gas outlets of the particle removers,
To specify the operation of the particle remover 78, the ion chambers 782 produce ionized gas by an ionizer and pressurize the ionized gas. The ionized gas is made of ionized air or ionized non-active gas such as ionized argon, ionized helium, ionized nitrogen or other ionized inert gas. When the wafer 80 passes through the particle remover 78, particles adherent to the surfaces of the wafer 80 are blown away by ionized gas with high-pressure sprayed from the gas outlets 786. A direction of the ionized gas is inclined downwardly at a predetermined angle (θ), which can efficiently remove the particles. A particle is attached on the wafer 80 by, for example, gravity, molecular attraction, static electricity or moisture. The particles attached on the wafer 80 by gravity are easily blown off by the ionized gas. If the particles are attached on the wafer 80 by molecular attraction or static electricity, the ionized gas can neutralize or discharge the static electricity of the particles since the ionized gas has an amount of ionic charges. The particles thus are detached from the wafer 80 and sucked into the particle remover 78 through the gas inlets 786. In other cases, if the particles are attached on the wafer 80 by moisture, the ionized gas can dissipate the moisture and then remove the particles. As the particles are bouncing from the wafer 80, the particle remover 78 sucks in the particles through the gas inlets 786 so that the particles cannot attached onto the wafer 80 again. The particles are kept in the intake chamber 781 and monitored by the particle remover 78. The particle remover 78 extracts information of the particles such as the quantity and sizes of the particles. Later, the particle remover 78 will adjust a flow rate of the ionized gas or a flow rate of the sucking according to the quantity and sizes of the particles. Therefore, the particle remover 78 is able to remove the particles on a front side 802 or a back side 803 of the wafer 80. Since the particle remover 78 removes the particles of the front side 802, the wafer 80 is cleaned and ready for etching or deposition processes. By using the particle remover 78, a partial etch or defects will not occur at the front side 802 of the wafer 80. In addition, since the particle remover 78 removes the particles from the back side 803, helium will not leak from the gap between the wafer 80 and an electrostatic chuck (ESC), and by consequence a helium alarm will not be triggered.
In brief, the particle removers are equipped adjacent to an orienter or around valves so that wafers are comprehensively cleaned. Further, the particle removers blow ionized gas on wafers and neutralize particles on the wafer. Particles at a front side of a wafer are removed so as to avoid formation of defects or a partial etch, and particles at a back side of the wafer are removed so as not to trigger a helium alarm. The particles are sucked and collected in the particle removers so that a manufacturing chamber is kept clean from particle contamination. In addition, the particle removers have a structure where each gas inlet is parallelly arranged with each gas outlet. This configuration provides a better efficiency and cleaning effect.
An apparatus for processing a semiconductor wafer includes a factory interface configured to couple with a manufacturing chamber. The factory interface includes a robot; an orienter adjacent to the robot; and a particle remover above the orienter and facing toward a wafer. The particle remover is configured to blow ionized gas on a surface of the wafer in order to remove particles.
In some embodiments, the apparatus further includes a particle remover below the orienter and facing toward the wafer, wherein a gap between the two particle removers allows the robot to pass through.
In some embodiments, the manufacturing chamber includes a load lock chamber coupled with the factory interface. The factory interface further includes a particle remover around a valve located between the load lock chamber and the factory interface.
In some embodiments, the particle remover is associated with the robot. The particle remover is configured to manipulate a speed of the robot.
In some embodiments, the particle remover includes a gas outlet facing the surface of the wafer and applying gas on the surface; a gas inlet adjacent to the gas outlet; and an ionizer configured to ionize gas prior to exiting the gas outlet.
In some embodiments, the gas outlet and the gas inlet are elongated slits.
In some embodiments, the particle remover is configured to analyze quantity and sizes of the particles entering the gas inlet. The particle remover manipulates a speed of the robot, a flow rate measured at the gas inlet and a flow rate measured at the gas outlet according to the quantity and sizes of the particles.
In some embodiments, the particle remover includes at least two gas outlets facing the surface of the wafer and applying gas on the surface; at least three gas inlets; and an ionizer configured to ionize gas prior to exiting the at least two gas outlets. Each gas inlet is arranged parallelly with each gas outlet.
In some embodiments, the at least two gas outlets and the at least three gas inlets are elongated slits.
An apparatus for processing a semiconductor wafer includes a buffer chamber configured to couple with a manufacturing chamber. The buffer chamber includes a robot configured to transfer a wafer to the manufacturing chamber; and a particle remover above a traveling path of the wafer and facing toward the traveling path. The particle remover is configured to blow ionized gas on a surface of the wafer and remove particles.
In some embodiments, the apparatus further includes a particle remover beneath the traveling path and facing toward the traveling path, wherein the particle remover vertically aligns with the particle remover above the traveling path.
In some embodiments, the apparatus further includes a plasma process chamber coupled with the buffer chamber; and a particle remover around a valve, which is located between the buffer chamber and the plasma process chamber.
In some embodiments, the apparatus further includes a deposition chamber coupled with the buffer chamber; and a particle remover around a valve, which is located between the buffer chamber and the deposition chamber.
In some embodiments, the apparatus further includes a diffusion chamber coupled with the buffer chamber; and a particle remover around a valve, which is located between the buffer chamber and the diffusion chamber.
In some embodiments, the particle remover is associated with the robot, and the particle remover is configured to manipulate a speed of the robot in accordance with quantity and sizes of particles collected by the particle remover.
A method for processing a semiconductor wafer includes providing a wafer to a factory interface; transferring the wafer to an orienter by using a first robot of the factory interface; removing particles by using a particle remover before moving to a manufacturing chamber; and transferring the wafer to the manufacturing chamber by using the first robot.
In some embodiments, the step of removing the particles by using the particle remover further includes ionizing gas by using the particle remover; blowing the gas on the wafer and then detaching particles from the wafer; sucking the particles by using the particle remover; and monitoring quantity and sizes of the particles by using the particle remover.
In some embodiments, the method further includes adjusting a speed of the first robot according to the quantity and sizes of the particles monitored by the particle remover; adjusting a flow rate of the gas according to the quantity and sizes of the particles monitored by the particle remover; and adjusting a flow rate of the sucking according to the quantity and sizes of the particles monitored by the particle remover.
In some embodiments, the method further includes transferring the wafer from a load lock chamber to a buffer chamber by using a second robot of the buffer chamber; removing particles before transferring the wafer into a plasma process chamber; transferring the wafer from the buffer chamber to the plasma process chamber by using the second robot; and transferring the wafer back to the buffer chamber.
In some embodiments, the method further includes removing particles before transferring the wafer into a deposition chamber; transferring the wafer from a buffer chamber to the deposition chamber by using a second robot of the buffer chamber; transferring the wafer back to the buffer chamber; removing particles before transferring the wafer into a diffusion chamber; transferring the wafer from the buffer chamber to the diffusion chamber; and transferring the wafer back to the buffer chamber.
The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.