Patent Application
20230402302
This application claims the benefit under 35 U.S.C. § 119(a) of European Application No. 22178369.9 filed Jun. 10, 2022, the contents of which are incorporated by reference herein in their entirety.
Aspects of the present disclosure relate to a system for transporting an electronic component. Further aspects of the present disclosure relate to a method for transporting an electronic component.
In semiconductor assembly, electronic components such as semiconductor dies often need to be transported between a source unit and a target unit. For example, the source unit may comprise a diced semiconductor wafer and the target unit may comprise a printed circuit board on which one or more of the dies on the diced semiconductor wafer need to be arranged. To enable such transfer, a system for transporting an electronic component is used. Such system may also referred to as pick-and-place apparatus or die placement apparatus, such as a die bonder or die sorter.
The abovementioned systems rely on relatively heavy and expensive mechanical and mechatronic modules to assemble small (<1 mm) components. In relation to the assembled components, the assembly equipment weighs at least seven orders of magnitude more, resulting in complex, expensive equipment as assembly speeds increase.
Levitation in acoustic or magnetic fields has been studied extensively for various assembly applications and are promising technologies to address the abovementioned problem. If the force field can be controlled accurately and fast, the machine complexity can be greatly simplified. Furthermore, no mechanical contact between the component and a pickup tool is required, lowering the risk of damage. In addition, without any mechanical components blocking the view, smart vision can be integrated to track the position of the small objects in the force field and to support alignment and inspection tasks.
For application in semiconductor assembly, several issues associated with levitation in acoustic or magnetic fields still need to be overcome. For example, the achievable positional accuracy of the levitating component should be acceptable given a particular application. In prior art approaches, the position of the levitating component suffers from oscillation thereby causing a positional inaccuracy when arranging the component onto a carrier. The Applicant has found that this positional inaccuracy has prevented successful application of the levitation concept in the abovementioned transporting systems.
Aspects of the present disclosure relate to a system for transporting an electronic component that addresses the abovementioned problem of positional inaccuracy. To this end, a system is provided that comprises a carrier for carrying the electronic component, and a transducer system comprising a plurality of transducers, wherein the transducer system is configured for generating a levitation field in which the carrier levitates. The system further comprises an input unit for arranging the electronic component onto the carrier, and an output unit for receiving the electronic component from the carrier. The system also comprises a controller for controlling the transducer system to change the levitation field for the purpose of moving the carrier from the input unit to the output unit.
Compared to prior art approaches, the system according to the present disclosure uses a carrier for carrying the electronic component to be transferred. Properties of this carrier, such as its shape, weight, density, or the like, can be tailored to the particular levitation field that is used. For example, when using diamagnetic levitation, the carrier can be made of suitable magnetic material. Furthermore, by using a different shape, weight, and/or density than the electronic component to be transferred a more stable positioning can be obtained. Compared to the electronic component to be transferred, the carrier can be made relatively large and flat. This ensures less positional oscillations in the levitation field when compared to the situation in which the electronic component to be transferred was levitating in the levitation field by itself.
The input unit may further comprise a first dispensing unit for dispensing a first attaching agent onto the carrier. This first attaching agent is configured to attach the electronic component to the carrier when receiving the electronic component. The first attaching agent may be a liquid, such as water. In this case, the electronic component may be held to the carrier by means of fluidic adhesion. In other embodiments, other liquids may be used, such as liquids having adhesive properties. The liquid is generally applied by allowing a suitable quantity of liquid to be dropped onto the carrier. To prevent the dispensing of the liquid from disturbing the levitation field, the dispensing unit is typically arranged at some distance from the carrier. Furthermore, the carrier may comprise a recess or other structure that aligns the droplet of the liquid and/or that forces the droplet to assume a pre-defined position and/or shape on the carrier. Furthermore, such recess or other structure may have an elongated shape that would cause the electronic component to assume a predefined position relative to the carrier when it is received from the input unit. Such alignment may be preferred when the electronic component is also elongated itself and needs to be arranged on a substrate or the like with a particular orientation.
The output unit may comprise a detaching unit for breaking the attachment of the electronic component to the carrier by the first attaching agent. Typically, the detaching unit breaks the attachment remotely, i.e. without mechanical interaction. This may be achieved by imparting some suitable form of energy onto the first attaching agent to cause the attachment to be broken. The attachment may be broken because the first attaching agent loses its adhesive properties and/or because the first attaching agent is at least partially removed. For example, the first attaching agent may comprise a photo-absorbing material, and the detaching unit may comprise a light source configured for illuminating the first attaching agent for the purpose of breaking the attachment by the first attaching agent. The light source may for example comprise a laser source. The first attaching agent may be configured to at least partially evaporate as a result of illuminating the first attaching agent. In this case, the received optical energy is converted into thermal energy that heats the first attaching agent to the point that it evaporates. Additionally, or alternatively, the absorption of heat may also cause the first attaching agent to exert a propulsion force onto the electronic component, thereby pushing the electronic component away from the carrier.
The output unit may comprise a holding unit, such as a chuck, for holding a substrate on which the electronic component is to be arranged. Typically, the substrate is plate-shaped and may comprise a printed circuit board. The output unit may also comprise a second dispensing unit for dispensing a second attaching agent onto the substrate for the purpose of attaching the electronic component received from the carrier on the substrate. Contrary to the first attaching agent, the second attaching agent should generally ensure a permanent fixation of the electronic component on the substrate. The second attaching agent may comprise an adhesive glue, solder, or the like.
The electronic component may be a semiconductor die. Furthermore, the input unit may be configured for holding a wafer comprising a plurality of physically separated semiconductor dies. Such a wafer may be a structured wafer in which dies are arranged in a different order than the order they were in during manufacturing and/or in which dies are arranged that originate from different wafers. Alternatively, such a wafer may also include a wafer that is obtained after dicing the wafer to thereby physically separate the individual dies.
The input unit may further comprise a releasing unit for releasing a semiconductor die from the wafer causing and/or allowing the released semiconductor die to be arranged on the carrier. The releasing unit is generally configured for releasing one semiconductor die at a time. The physically separated semiconductor dies may be attached to a tape, foil, or film using a third attaching agent.
The releasing unit may comprise a needle and an actuator for bringing the needle into and out of engagement with a die among the plurality of physically separated dies on the wafer by pushing on a backside of the tape, foil, or film. As a result of this engagement, the tape, foil, or film may bulge outwardly and the corresponding semiconductor detaches from the tape, foil, or film. Alternatively, the releasing unit may comprise a light source for illuminating the third attaching agent for the purpose of breaking the attachment of a semiconductor die among the physically separated semiconductor dies to the tape, foil, or tape, by the third attaching agent. In this case, the third attaching agent is as a photo-absorbing adhesive. Upon absorbing the optical energy, the third attaching agent may undergo a chemical transition thereby losing its adhesive properties. Alternatively, the third attaching agent may at least partially evaporate and/or ablate, thereby releasing the semiconductor die.
Relative to the Earth's gravitational field, the input unit can be arranged above the carrier at a time of arranging the electronic component on the carrier. In this case, the input unit can be configured to cause the electronic component to fall onto the carrier. Additionally, or alternatively, relative to the Earth's gravitational field, the output unit can be arranged below the carrier at a time of receiving the electronic component from the carrier. In this case, the output unit can be configured to cause the electronic component to fall from the carrier. Alternatively, aspects of the present disclosure relate to embodiments in which the carrier is moved against the wafer, i.e. making physical contact, when receiving the semiconductor die, and/or in which the carrier is moved against the substrate when arranging the semiconductor die onto the substrate. This equally applies to embodiments in which other electronic components are transferred.
The plurality of transducers may comprise a plurality of acoustic transducers configured for generating soundwaves. In this case, the levitation field is an acoustic levitation field. The soundwaves generated by the plurality of acoustic transducers may have a frequency in a range between 20 Hz and 200 kHz. The transducers can be configured to generate an acoustic potential well in which the carrier and the component carried by the carrier can be trapped. The controller can be configured for controlling the transducer system to change a position and/or orientation of the acoustic potential well for the purpose of moving the carrier.
The carrier may have a first surface configured to support the electronic component, wherein a maximum thickness of the carrier in a direction perpendicular to the first surface is less than ⅓ times a wavelength of the soundwaves generated by the acoustic transducers. Generally, the combination of carrier and electronic component should be contained in the acoustic potential well to allow proper control of position and orientation in the levitation field. A surface area of the first surface can be at least 3 times greater than a maximum cross-sectional area of the electronic component, more preferably 10 times greater. Typically, the acoustic potential well is larger in a direction perpendicular to a propagation direction of the soundwaves than in a direction parallel to the propagation direction. For example, when the transducers are arranged to emit soundwaves in a vertical direction, the acoustic potential well is much wider than it its high. Furthermore, the acoustic potential well and/or the carrier can be elongated. This allows for self-alignment of the carrier in the acoustic potential well allowing a predictable orientation of the electronic component when it is released from the carrier in the output unit.
The first surface can be a rectangular or oval. Moreover, the carrier can be made from one or more of the materials out of the group consisting of polymers and/or low-density materials such as low-density metals e.g. magnesium or beryllium, low-density composite materials e.g. carbon-based, or low-density ceramics, wherein the low-density material preferably has a density less than 2000 kg/m3.
The transducer system may comprise one or more reflectors for reflecting the soundwaves emitted by the transducers for the purpose of creating standing waves. Generally, the acoustic levitation field comprises a pattern of standing waves. These standing waves may be generated by letting two or more oppositely directed soundwaves interfere. When using one or more reflectors, the generated soundwaves interfere with their reflections for the purpose of generating the standing wave pattern.
The system may comprise a housing in which the acoustic field is generated, wherein the one or more reflectors are at least partially formed by an inner wall of the housing. When a wafer is used holding the electronic component to be transferred, this wafer may partially form one or more reflectors. For example, the wafer may be arranged in an upside-down manner relative to the Earth's gravitational field with the transducers being arranged below the wafer and the carrier in between the transducers and the wafer. In such case, the standing wave pattern is generated using the soundwaves emitted by the transducers and the soundwaves that are reflected off the wafer.
Similarly, at the output unit, the substrate may partially form one or more reflectors. For example, the substrate may be arranged upwardly oriented relative to the Earth's gravitational field with the transducers being arranged above the substrate and the carrier in between the transducers and the substrate. In such case, the standing wave pattern is generated using the soundwaves emitted by the transducers and the soundwaves that are reflected off the substrate.
The system may generally be divided into a number of parts or segments. For example, the system may comprise an input part in which the input unit is arranged in combination with some of the plurality of transducers. The system may further comprise an output part in which the output unit is arranged in combination with some of the plurality of transducers, and a transfer part arranged in between the input part and the output part in which some transducers of the plurality of transducers are arranged.
Some of the plurality of transducers arranged in the transfer part can be configured for rotating and/or flipping the carrier while supporting the electronic component arranged thereon to cause the electronic component to face the output unit at a time when the output unit receives the electronic component from the carrier. For example, in the embodiments discussed above, the input unit was arranged above the carrier and the output unit below the carrier at a time of arranging the electronic component onto the carrier or receiving the electronic component from the carrier, respectively. To allow this positioning of the input unit and the output unit, the carrier with the electronic component needs to be rotated and/or flipped. Generally, the rotation and/or flipping is performed about a rotational axis that is perpendicular to the direction in which the transducers and input unit are separated. For example, when arranging the input unit vertically separated from the transducers, the rotational axis may be horizontal.
The system may further comprise a localization system for determining a position and/or orientation of the carrier and/or the electronic component carried by the carrier. In this case, the controller is configured to control the transducer system in dependence of the determined position and/or orientation. The localization system may be configured to determine the position and/or orientation of the electronic component by itself. Alternatively, the localization system may be configured to determine the position and/or orientation of the carrier, with the electronic component having a pre-defined position and/or orientation relative to the carrier.
The localization system may comprise a vision system. This 3D vision system determines the position and/or orientation inside the housing in which the acoustic field is generated. This system may comprise a stereo camera setup and/or structured lighting for triangulation-based measurements. Alternative imaging techniques are based on computational imaging and digital holography. The minimal measurement frequency can be around 1 kHZ. Additionally, this vision system may be configured to align the carrier with the electronic component on the input unit for correcting positioning of the semiconductor component on the carrier. The vision system can also be used to align the semiconductor component on the carrier with the substrate for correct positioning of the electronic component on the substrate. Additionally, or alternatively, the localization system can be configured to determine the position and/or orientation of the carrier and/or the position and/or orientation of the electronic component carried by the carrier using echo-localization. When using an acoustic levitation field, the plurality of transducers can be further configured for generating soundwaves used for performing this echo-localization. These soundwaves may have a different frequency when compared to the soundwaves for creating the levitation field to avoid disturbing the levitation field.
The system can be configured to transport a plurality of electronic components simultaneously. For example, when using acoustic levitation, a plurality of acoustic cavities are generated. In this case, the transducer system can be configured to trap each of the plurality of electronic components that is to be transported simultaneously in a respective acoustic potential well.
Furthermore, the controller can be configured for returning the carrier from the output unit to the input unit after having transported the electronic component for the purpose of transporting of an other electronic component. In particular when using a first attaching agent such as water, the carrier can be re-used multiple times as the contamination of the carrier caused by the first attaching agent is limited or non-existent.
According to a further aspect of the present disclosure a method for transporting an electronic component is provided that comprises generating a levitation field in which a carrier is levitating, arranging the electronic component onto the carrier while the carrier is levitating, changing the levitation field for moving the carrier with the electronic component carried by the carrier, and removing the electronic component from the carrier.
Preferably, the levitation field is an acoustic levitation field, although the present disclosure equally relates to other types of levitation fields, such as a magnetic levitation field. In case the levitation field is an acoustic levitation field, the carrier and the electronic component carried by the carrier are trapped in an acoustic potential well. Moving the carrier with the electronic component carried by the carrier may then comprise changing a position and/or orientation of the acoustic potential well.
The electronic component can be a semiconductor die among a plurality of physically separated semiconductor dies comprised by a wafer. Arranging the electronic component onto the carrier may comprise releasing a semiconductor die from the wafer causing and/or allowing the released semiconductor die to be arranged on the carrier. The physically separated semiconductor dies may be attached to a tape, foil, or film using a third attaching agent, such as an adhesive. In this case, releasing a semiconductor die may comprise illuminating the third attaching agent for the purpose of breaking the attachment of a semiconductor die among the physically separated semiconductor dies by the third attaching agent.
Generating a levitation field may comprise using a plurality of transducers for generating soundwaves and allowing the soundwaves to be reflected by one or more reflectors for the purpose of creating standing waves, wherein the one or more reflectors are at least partially formed by the wafer.
The method may further comprise dispensing a first attaching agent on the carrier prior to arranging the electronic component on the carrier, wherein the first attaching agent attaches the electronic component to the carrier. In this case, removing the electronic component may comprise breaking the attachment of the electronic component to the carrier by the first attaching agent. The first attaching agent may comprise a photo-absorbing material, and said breaking the attachment may comprise illuminating the first attaching agent using a light source.
The method may comprise allowing a plurality of carriers and a corresponding plurality of electronic components carried by the carriers to simultaneously levitate in the levitating field. In this case, the carriers and corresponding electronic components may be trapped in respective acoustic cavities. The method may comprise simultaneously moving the carriers with the electronic components carried by the carriers by changing a position and/or orientation of the acoustic cavities.
So that the manner in which the features of the present disclosure can be understood in detail, a more particular description is made with reference to embodiments, some of which are illustrated in the appended figures. It is to be noted, however, that the appended figures illustrate only typical embodiments and are therefore not to be considered limiting of its scope. The figures are for facilitating an understanding of the disclosure and thus are not necessarily drawn to scale. Advantages of the subject matter claimed will become apparent to those skilled in the art upon reading this description in conjunction with the accompanying figures, in which like reference numerals have been used to designate like elements, and in which:
System 100 comprises an input unit 110 for arranging the electronic component to be transferred onto a carrier. Input unit 110 comprises a first dispensing unit 111 for dispensing a first attaching agent onto the carrier, and a releasing unit 112 for releasing a semiconductor die from the wafer causing and/or allowing the released semiconductor die to be arranged on the carrier.
System 100 further comprises an output unit 120 for receiving the electronic component from the carrier onto a substrate in the form of a printed circuit board. Output unit 120 comprises a detaching unit 121 for breaking the attachment of the electronic component to the carrier by the first attaching agent. Output unit 120 optionally further comprises a second dispensing unit 122 for dispensing a second attaching agent onto the substrate for the purpose of attaching the electronic component received from the carrier on the substrate.
System 100 comprises a transducer system 130 comprising a plurality of transducers 131 that each emit a soundwave having a frequency in the range between 20 kHz and 200 kHz. The transducer system is configured for generating a levitation field in which the carrier levitates. System 100 also comprises a controller 140 for controlling transducer system 130 to change the levitation field for the purpose of moving the carrier from input unit 110 to output unit 120. Controller 140 further controls first dispensing unit 111, releasing unit 112, detaching unit 121, and optionally second dispensing unit 122.
System 100 comprises a localization system 150 for determining a position and/or orientation of the carrier and/or the electronic component carried by the carrier. Controller 140 is configured to control transducer system 130 in dependence of the determined position and/or orientation. Optionally, system 100 may comprise an inspection system 160 for inspecting the electronic component and/or carrier during various stages of transporting the electronic component. Controller 140 can be configured to control transducer system 130 in dependence of an output of inspection system 160. Inspection system 160 may comprise one or more optical cameras 161.
Next, two embodiments of a system for transporting an electronic component in accordance with an aspect of the present disclosure will be described in more detail referring to
System 200A comprises a housing 210 in which transducers 131 are arranged. Housing 210 is made from acoustically reflective material. The soundwaves emitted by transducers 131 reflect off housing 210 causing a standing wave pattern to be generated inside housing 210. The standing wave pattern comprises a plurality of acoustic cavities.
As shown, input unit 110 comprises a dispensing unit 111 that arranges a droplet 111A of liquid, such as water, on carrier 220. This shown in insert III of
As shown in insert I of
Inside input part 201, transducers 131 are arranged at one side of housing 210, whereas at an opposing side of housing 210 a wafer 230A is arranged that holds a plurality of semiconductor dies 230. As shown in insert II of
The soundwaves generated by transducers 131 and the soundwaves reflected off wafer 230A and housing 210 jointly create a standing wave pattern. Insert II also illustrates the Earth's gravitational force F demonstrating that if a semiconductor die 230 is released from wafer 230A it will fall towards carrier 220.
Inside second part 203, transducers 131 are arranged along an inner wall of housing 210 at various vertical positions. Moreover, the upper part of housing 210 acts as reflectors R and transducers 131 arranged in the lower part of housing 210 act as sources S. In other embodiments, transducers 131 are arranged both in the upper and lower parts of housing 210. The configuration of transducers 131 allows the acoustic cavities to be rotated and/or flipped along a rotational axis that is parallel to the horizontal direction from input part 201 to output part 202 or along a horizontal axis that is perpendicular to the horizontal direction from input part 201 to output part 202.
Output unit 120, which is arranged inside output part 202, comprises a holding unit 240 for holding a substrate 241 on which semiconductor die 230 needs to be arranged. Output unit 120 further comprises a detaching unit in the form of a laser source 121. Substrate 241, which can be in the form of a printed circuit board, is provided with an attaching agent 242. When laser source 121 illuminates the droplet of liquid 111A by which semiconductor die 230 is attached to carrier 220, the attachment between semiconductor die 230 and carrier 220 is broken and semiconductor die 230 falls on attaching agent 242 for allowing semiconductor die 230 to become fixated relative to substrate 241. It should be noted that attaching agent 242 may comprise adhesive glue, solder, or the like, which may require an additional step, such as curing and/or heating, to be performed to achieve the fixation.
As shown in insert II, the configuration of transducers 131 in output part 202 is flipped when compared to input part 201. Consequently, carrier 220 and semiconductor die 230 carried by carrier 220 need be rotated or flipped between input part 201 and output part 202. As explained before, this is performed inside transfer part 203.
Localization for determining a position and/or orientation of carrier 220 and/or semiconductor die 230 can obtained by using echo-localization. The soundwaves required for performing echo-localization can be emitted using transducers 131 albeit at a different frequency. Controller 140 is configured for controlling transducers 131 in dependence of a determined position of carrier 220 and/or semiconductor die 230. More in particular, the position and/or orientation of the acoustic potential well in which carrier 220 and semiconductor die 230 are trapped is changed. Such change can be effectuated by changing an amplitude and/or phase of the soundwaves that are generated by transducers 131.
Insert III illustrates the position of carrier 220 and semiconductor die 230 at various stages during transport from input unit 110 to output unit 120. As shown, using numerals 3A and 3B, carrier 220 is flipped when inside transfer part 203.
System 200A also comprises optical cameras 161 to monitor the transfer process and/or for performing various quality checks of carrier 220 and/or semiconductor die 230. Based on the output of cameras 161 or the output of an image processing unit that processes the images of optical cameras 161, controller 140 may control transducers 131 for performing corrective measures. For example, if a damaged and/or incorrectly placed semiconductor die 230 is detected by an optical camera 161, controller 140 may control transducers 131 to move carrier 220 to a separate location, optionally also provided with a detaching unit, for discarding semiconductor die 230 and/or carrier 220.
After semiconductor die 230 has been arranged on substrate 241, carrier 220 may return to input part 201 where it will receive a next droplet of liquid 111A for transporting a next semiconductor die 230 on wafer 230A.
Although
An advantage of the
In the above, the present disclosure has been described using detailed embodiments thereof. However, the present disclosure is not limited to these embodiments. Instead, various modifications are possible without departing from the scope of the present disclosure which is defined by the appended claims and their equivalents.
For example, the system is generally adapted for transporting an electronic component through air or another gaseous medium in case acoustic levitation is employed. However, the present disclosure does not exclude other media in which an electronic component can be transported such as a liquid. In case a liquid is used instead of air, the frequency of the generated soundwaves is generally different. For example, the frequency can be in the range between 100 kHz and 1 MHz.
Particular and preferred aspects of the disclosure are set out in the accompanying independent claims. Combinations of features from the dependent and/or independent claims may be combined as appropriate and not merely as set out in the claims.
The scope of the present disclosure includes any novel feature or combination of features disclosed therein either explicitly or implicitly or any generalization thereof irrespective of whether or not it relates to the claimed disclosure or mitigate against any or all of the problems addressed by the present disclosure. The applicant hereby gives notice that new claims may be formulated to such features during prosecution of this application or of any such further application derived therefrom. In particular, with reference to the appended claims, features from dependent claims may be combined with those of the independent claims and features from respective independent claims may be combined in any appropriate manner and not merely in specific combinations enumerated in the claims.
Features which are described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, various features which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub combination.
The term “comprising” does not exclude other elements or steps, the term “a” or “an” does not exclude a plurality. Reference signs in the claims shall not be construed as limiting the scope of the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 22178369.9 | Jun 2022 | EP | regional |
