Mechanisms for cleaning load ports of semiconductor process tools

Embodiments of mechanisms for cleaning load ports of semiconductor process tools are provided. The automatic system includes a vacuum cleaner, a rail, and a transport mechanism. The transport mechanism is moveably disposed on the rail and transfers the vacuum cleaner along the rail. The automatic system also includes a system controller. The system controller is connected to the semiconductor process tools and the transport mechanism to detect which load port is unoccupied, such that the system controller controls the transport mechanism to transfer the vacuum cleaner to the unoccupied load port to perform a cleaning process.

BACKGROUND

As the sizes of semiconductor integrated circuits and the design rule for line widths have decreased, the issue of contamination of the devices and substrates (or wafers) during processing has become more important. The demand for extremely clean processing environments for these devices and substrates has increased.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

The making and using of the embodiments of the disclosure are discussed in detail below. It should be appreciated, however, that the embodiments can be embodied in a wide variety of specific contexts. The specific embodiments discussed are merely illustrative, and do not limit the scope of the disclosure.

Some variations of the embodiments are described. Throughout the various views and illustrative embodiments, like reference numbers are used to designate like elements.

FIGS. 1A and 1Bare schematic views of an automatic system100and a semiconductor process tool200, in accordance with some embodiments. It should be noted that there may be a number of semiconductor process tools200, but for the sake of simplicity,FIGS. 1A and 1Bmerely show one of the semiconductor process tool200.

As shown inFIG. 1A, the automatic system100includes wafer carriers110, a transport mechanism120, a rail130and a system controller140, in accordance with some embodiments. For the sake of simplicity,FIGS. 1A and 1Bmerely show one of the wafer carriers110, and the wafer carrier110is illustrated as follows. The other carriers110not shown may have the same structure as the wafer carrier110shown inFIGS. 1A and 1B.

The wafer carrier110is configured to carry a number of wafers10. The wafer carrier110includes, for example, a front opening unified pod (FOUP). The wafer carrier110may include different FOUP sizes such as 130 millimeter (mm) or 450 mm. Other types and/or sizes of the wafer carrier110may be used.

FIG. 2is a perspective view of the wafer carrier110ofFIG. 1A, in accordance with some embodiments. As shown inFIGS. 1A and 2, the wafer carrier110includes a housing112, handle grips114, and a robotic flange (or a knob)116, in accordance with some embodiments. The housing112may be a box-type housing including an open front side112aand a door112b.

The door112bis detachably installed at the front side112aof the housing112, in accordance with some embodiments. Specifically, the door112bmay be installed at the front side112aby a locking structure (not shown). The door112bmay be separated from the housing112when the locking structure is released by a door opener.

The handle grips114are attached to opposite sides112dand112eof the housing112to facilitate carrying the wafer carrier110. Because of the view angle ofFIG. 2, the handle grip114attached to the side112eis not shown. The robotic flange116is installed on a top surface112cof the housing112so that the transport mechanism120can lift up the wafer carrier110by, for example, grasping the robotic flange116.

The transport mechanism120may be moveably disposed on the rail130. The transport mechanism120may grasp the robotic flange116and move along the rail130to transfer the wafer carrier110to (or away from) the semiconductor process tool200. The transport mechanism120includes, for example, an overhead hoist transfer (OHT) system. The transport mechanism120may also be referred as a wafer carrier transport mechanism.

The transport mechanism120is designed to perform a transportation controlled by the system controller140. The system controller140is connected to the semiconductor process tools200and the transport mechanism120and/or the rail130, in accordance with some embodiments. The system controller140controls the transport mechanism120to grasp the wafer carrier110and move to a desired position.

The system controller140may receive signals from the semiconductor process tools200. According to the signals, the system controller140controls the transport mechanism120to transfer the wafer carrier110with the wafers10therein to the semiconductor process tool200requiring the wafers10. The system controller140may include a computer integrated manufacturing system (CIM system).

The semiconductor process tool200is used for semiconductor fabrication. For example, the semiconductor process tool200includes, a deposition tool, an electroplating tool, an etch tool, a thermal furnaces, a developing tool, etc. The semiconductor process tool200has a load port210, a gate220, a door opener230, a front chamber240, a transfer robot250, a load-lock chamber260, and a process chamber270, in accordance with some embodiments.

The load port210is equipped at a front side200aof the semiconductor process tool200to be loaded with the wafer carrier110. The gate220is formed at the front side200aand is above the load port210. The gate220is between the front chamber240and the exterior clean room300where the wafer carrier110is transferred. The gate220is closed by the door opener230in the front chamber240.

As shown inFIG. 1A, the wafer carrier110may be loaded on the load port210by the transport mechanism120. In the meantime, the door112bof the wafer carrier110may face the gate220.

As shown inFIG. 1B, the door opener230opens the door112bof the wafer carrier110and moves downwardly with the door112b, in accordance with some embodiments. Accordingly, the wafer carrier110is opened, and the wafers10are loaded into the semiconductor process tool200. The gates220, as well as the front chamber240, are isolated from the exterior clean room300by the housing112of the wafer carrier110.

The cleanness of the front chamber240should be kept high (e.g. class100). The transfer robot250is disposed in the front chamber240. The transfer robot250is configured to load the wafers10in the wafer carrier110into a load-lock chamber260or to unload the wafers10from the load-lock chamber260into the wafer carrier110. The process chamber270is disposed at a rear portion of the load-lock chamber260. The wafers10may be transferred from the load-lock chamber260to the process chamber270to be processed.

As shown inFIGS. 1A and 1B, contaminants (e.g. dust or particles)20in the exterior clean room300may be deposited on a top surface210aof the load port210. When the wafer carrier110is opened, the contaminants20may float into the front chamber240and contaminate the front chamber240and the wafers10.

In some embodiments, to solve this problem, the contaminants20are cleaned manually. However, the staffs need to walk in the exterior clean room300to find out which of the load ports210are not occupied by the wafer carriers110. The manual cleaning method takes a lot of time and there may be some load ports210missed being cleaned. Therefore, it is desired to find alternative mechanisms for timely cleaning the load port.

FIG. 3Ais a side view of the automatic system100and the semiconductor process tool200, in accordance with some embodiments.FIG. 3Bis a side view of the automatic system100and the semiconductor process tools200and200′, in accordance with some embodiments.

As shown inFIG. 3A, the automatic system100may further include a vacuum cleaner150. In some embodiments, before the wafer carrier110is loaded on the load port210, the transport mechanism120transfers the vacuum cleaner150onto the top surface210aof the load port210to clean the top surface210a. The contaminants20on the load port210may be sucked into the vacuum cleaner150.

FIG. 4Ais a cross-sectional view of the vacuum cleaner150and a portion of the semiconductor process tool200, in accordance with some embodiments.FIG. 4Bis an enlarged view of a portion of a dust bag of the vacuum cleaner150ofFIG. 4A, in accordance with some embodiments.FIG. 4Cis an enlarged view of a portion of a filter of the vacuum cleaner150ofFIG. 4A, in accordance with some embodiments.FIG. 5is a perspective view of the vacuum cleaner150, in accordance with some embodiments.

As shown inFIGS. 4A and 5, the vacuum cleaner150includes a cleaner carrier151and an inner apparatus159in the cleaner carrier151, in accordance with some embodiments. The cleaner carrier151has a similar structure as that of the wafer carrier110(as shown inFIG. 2). In some embodiments, external appearances of the cleaner carrier151and the wafer carrier110are substantially the same.

The cleaner carrier151includes a cleaner housing151a, cleaner handle grips151b, and a cleaner robotic flange151c, in accordance with some embodiments. The cleaner housing151a, the cleaner handle grips151b, and the cleaner robotic flange151care similar to the housing112, the handle grips114, and the robotic flange116of the wafer carrier110(as shown inFIG. 2), respectively.

The cleaner housing151amay be a box-type housing including an open front side151dand a door151e. The door151eis detachably installed at the front side151dof the cleaner housing151a. The door151emay be opened to clean the contaminants20sucked in the cleaner housing151a.

The handle grips151bare attached to opposite sides151gand151hof the cleaner housing151ato facilitate carrying the vacuum cleaner150. Because of the view angle ofFIG. 5, the handle grip151battached to the side151his not shown. The robotic flange151cis installed on a top surface151fof the cleaner housing151a. Therefore, the transport mechanism120can lift up the vacuum cleaner150by, for example, grasping the robotic flange151c(as shown inFIG. 3A). The transport mechanism120may grasp the robotic flange151cand move along the rail130to transfer the vacuum cleaner150to (or away from) the semiconductor process tool200.

Although the cleaner housing151ais similar to the housing112of the wafer carrier110(as shown inFIG. 2), there are still some differences between the cleaner housing151aand the housing112. The cleaner housing151ahas an inner space160including a first chamber161, a second chamber162and a third chamber163. The second chamber162is above and connected with the first chamber161. The third chamber163is located between and isolated from the first chamber161and the second chamber162.

The cleaner housing151ahas a number of suction openings164and exhaust vents165, in accordance with some embodiments. The suction openings164penetrate through the bottom of the cleaner housing151ato connect the first chamber161to the exterior clean room300. The exhaust vents165penetrate through the rear portion of the cleaner housing151ato connect the second chamber162to the exterior clean room300.

The inner apparatus159is located in the inner space160for sucking, filtering out and collecting contaminants20on the load port210. The inner apparatus159includes a suction fan152, a motor153, a dust bag154, a control unit155, a battery156, and a sensor400, in accordance with some embodiments.

The suction fan152may be located in the first chamber161and on the suction openings164. The suction fan152is configured to generate a suction force toward the second chamber162. The motor153is connected with the suction fan152to provide a rotational force to the suction fan152. In some embodiments, the motor153is located in the first chamber161.

The dust bag154is detachably installed in the second chamber162and on an air flow path30to filter out and collect the contaminants20sucked in by the suction fan152. The door151emay be opened, such that the dust bag154may be detached from the cleaner housing151ato be cleaned. In some other embodiments, the dust bag154is replaced by a new dust bag. As shown inFIG. 4B, in some embodiments, the dust bag154has a number of pores154aeach having a diameter D1 less than or equal to 0.3 μm to filter out particles with a diameter larger than 0.3 μm.

As shown inFIG. 4A, the vacuum cleaner150further includes a filter157, in accordance with some embodiments. The filter157is disposed between the dust bag154and the rear portion of the cleaner housing151ato cover the exhaust vents165. The filter157may filter out the contaminants20in the air penetrating through the dust bag154. As shown inFIG. 4C, in some embodiments, the filter157has a number of pores157aeach having a diameter D2 less than or equal to 0.2 μm to filter out particles with a diameter larger than 0.2 μm. In some embodiments, the diameter D2 of the pores157aof the filter157is smaller than the diameter D1 of the pores154aof the dust bag154.

As shown inFIG. 4A, the sensor400is installed on the bottom of the cleaner housing151ato detect the distance between the cleaner housing151aand the load port210, in accordance with some embodiments. The control unit155is disposed in the third chamber163to control various operations of the vacuum cleaner150.

The control unit155may receive a start signal from the sensor400when the distance between the cleaner housing151aand the load port210is less than a predetermined distance. Therefore, the control unit155receiving the start signal may start the cleaning operation. The control unit155may receive a stop signal from the sensor400when the distance between the cleaner housing151aand the load port210is larger than the predetermined distance. Therefore, the control unit155receiving the stop signal may stop the cleaning operation.

The predetermined distance ranges, for example, from about 15 cm to about 30 cm. In some embodiments, the predetermined distance is 30 cm. In some embodiments, the predetermined distance is 15 cm. The predetermined distance may be adjusted according to requirements.

The battery156may be disposed in the third chamber163to supply power for operating the vacuum cleaner150. In some embodiments, the battery156is a rechargeable battery.

In some embodiments, the vacuum cleaner150further includes a number of brushes158. The brushes158may be rotatably mounted on the bottom of the cleaner housing151a. The brushes158are configured to brush the top surface210aof the load port210so as to facilitate sucking up the contaminants20. The brushes158may horizontally rotate. The brushes158are located between (or adjacent to) the suction openings164, in accordance with some embodiments.

The cleaning operation (or the cleaning process) of the vacuum cleaner150according to some embodiments will be described as follows.

When the control unit155receives the start signal from the sensor400, the control unit155controls the motor153to provide a rotational force to the suction fan152. Therefore, a suction force is generated in the first chamber161and the second chamber162by the suction fan152.

Afterwards, by the suction force, the contaminants20are sucked into the second chamber162through the first chamber161. The sucked air may flow along the air flow path30shown inFIG. 4A. The sucked contaminants20may be filtered by the dust bag154and the filter157on the air flow path30. When the control unit155receives the stop signal from the sensor400, the control unit155stops the cleaning operation of the vacuum cleaner150.

In some embodiments, the operating time of the vacuum cleaner150ranges from about 3 seconds to about 8 seconds. In some embodiments, the operating time of the vacuum cleaner150is about 5 seconds.

In some embodiments, as shown inFIG. 3B, after the cleaning operation is stopped, the transport mechanism120may transfer the vacuum cleaner150to another load port210′ so as to perform another cleaning operation. The system controller140may detect which load port is unoccupied by a wafer carrier110. Therefore, the system controller140may control the transport mechanism120to transfer the vacuum cleaner150to the unoccupied load port210′.

In some embodiments, the unoccupied load port210′ belongs to another semiconductor process tool200′. In some other embodiments, the unoccupied load port210′ also belongs to the semiconductor process tool200(not shown). That is, the semiconductor process tool200may have both the load ports210and210′ (not shown).

In some embodiments, the transport mechanism120grasps the vacuum cleaner150during the whole operating time for transferring the vacuum cleaner150away from the load port210in a timely manner. The timely transfer of the vacuum cleaner150may reduce the occupied time of the load port210, such that the wafer carrier110may be loaded on the cleaned load port210without being delayed.

FIG. 6is a side view of an automatic system100and a semiconductor process tool200, in accordance with some embodiments. In some embodiments, as shown inFIG. 6, when the voltage level of the battery156(as shown inFIG. 4A) is low, the transport mechanism120transfers the vacuum cleaner150to a charge station170so as to charge the battery156of the vacuum cleaner150.

In some embodiments, the automatic system100has many rails (not shown), and the vacuum cleaner150and the wafer carrier110are transferred along different rails.

As described above, the vacuum cleaner150has an external appearance similar to (or substantially the same as) that of a front opening unified pod. Therefore, the vacuum cleaner150is able to be automatically transferred by the transport mechanism120. The vacuum cleaner150of the automatic system100may automatically, quickly, timely and frequently clean the load ports210of the semiconductor process tools200. Therefore, the automatic system100with the vacuum cleaner150may clean the load ports more efficiently than manual cleaning. The system controller140may control (and record) the cleaning frequency of each of the semiconductor process tools200according to requirements. The cleanness of the load ports210is therefore properly maintained. As a result, the cleanness of the front chamber240is also properly maintained. Accordingly, yield is significantly increased. When the size of the wafers10increases, the size of the load ports210increases as well. The size of the vacuum cleaner150may accordingly increase to increase the cleaned area to match the enlarged load port210.

Embodiments of mechanisms for cleaning load ports of one or more semiconductor process tools are provided. A vacuum cleaner automatically transferred by a transport mechanism is used to automatically clean load ports of semiconductor process tools. The vacuum cleaner is able to quickly and timely clean the load ports, and therefore the cleaning efficiency is significantly improved. Since the cleanness of the load ports and the front chambers is improved, yield is also greatly increased.

In accordance with some embodiments, an automatic system for cleaning load ports of semiconductor process tools is provided. The automatic system includes a vacuum cleaner, a rail, and a transport mechanism. The transport mechanism is moveably disposed on the rail and transfers the vacuum cleaner along the rail. The automatic system also includes a system controller. The system controller is connected to the semiconductor process tools and the transport mechanism to detect which load port is unoccupied, such that the system controller controls the transport mechanism to transfer the vacuum cleaner to the unoccupied load port to perform a cleaning process.

In accordance with some embodiments, a vacuum cleaner for cleaning load ports of semiconductor process tools is provided. The vacuum cleaner includes a cleaner carrier. The cleaner carrier has an external appearance similar to that of a front opening unified pod to facilitate being automatically transferred by a wafer carrier transport mechanism to the load ports. The cleaner carrier has an inner space, a number of suction openings, and a number of exhaust vents, wherein the suction openings penetrate through a bottom of the cleaner carrier, and the exhaust vents penetrate through the cleaner carrier. The vacuum cleaner also includes an inner apparatus for sucking, filtering out and collecting contaminants on the load ports. The inner apparatus is located in the inner space of the cleaner carrier.

In accordance with some embodiments, a method for cleaning load ports of semiconductor process tools is provided. The method includes transporting a vacuum cleaner by a wafer carrier transport mechanism to one of the load ports. The method also includes cleaning the load port by the vacuum cleaner. The method further includes transporting the vacuum cleaner away from the load port.