Product holding device, product holding method, and semiconductor device production apparatus

Abstract

This semiconductor device production apparatus (10) is provided with: a stage (32) on which a product (100) is placed; a vibration element (38) that applies ultrasonic vibration to the product (100) via the stage (32) to generate, on the surface of the product (100), a sound field (70) that inhibits entry of falling foreign matter; and an ionizer (60) that discharges electricity from at least one of the foreign matter (110) and the product (100).

Description

Product holding device, product holding method, and semiconductor device manufacturing device

[0001] This specification discloses a product holding device, a product holding method, and a semiconductor device manufacturing device that hold products while keeping them clean.

[0002] Precision equipment such as semiconductor devices must be free from foreign matter during the manufacturing process and storage period. However, when a product undergoes a specific process for manufacturing, the tools used to perform the process move, and this movement can cause minute foreign matter to fall onto the product's surface and adhere to it. Furthermore, during temporary storage of a product, minute foreign matter floating in the storage space can adhere to the product's surface during the floating process.

[0003] Therefore, technologies using ultrasonic waves have been proposed to remove foreign matter adhering to the surface of products. However, because a certain amount of force is required to separate and remove foreign matter once it has adhered to a product, even with ultrasonic waves, it is difficult to separate and remove the foreign matter from the product, and the foreign matter often remains on the product. Furthermore, conventional technologies require a dedicated process to remove the adhering foreign matter, which complicates the manufacturing process and increases the takt time.

[0004] Therefore, some techniques have been proposed to prevent foreign matter from adhering to the surface of a product. For example, Patent Document 1 discloses a technique in which a collection electrode is disposed around a sample and a voltage of the same polarity as the voltage applied to the sample is applied to the collection electrode. This allows the collection electrode to capture most of the foreign matter, such as particles, that are attracted by the electric field. As a result, it is possible to prevent foreign matter from adhering to the surface of the sample to some extent.

[0005] JP 2016-106374 A

[0006] However, in Patent Document 1, the collection electrodes are arranged only around the periphery of the sample. Therefore, if the sample is large and the distance from the center of the sample to the collection electrodes is large, the collection electrodes cannot capture foreign matter that falls near the center of the sample. In other words, there has not been a conventional technology that can effectively prevent foreign matter from adhering to the surface of a product.

[0007] Therefore, this specification discloses a product holding device, a product holding method, and a semiconductor device manufacturing device that can more reliably prevent foreign matter from adhering to products.

[0008] The semiconductor device manufacturing apparatus disclosed in this specification is characterized by comprising a stage on which a product is placed, a vibration source that applies ultrasonic vibrations to the product via the stage to generate a sound field on the surface of the product that inhibits the intrusion of falling foreign objects, and an ionizer that de-electrifies at least one of the foreign objects and the product.

[0009] In this case, the ionizer may irradiate the space surrounding the product with ions or electromagnetic waves to neutralize the foreign matter floating in the space surrounding the product.

[0010] The ionizer may irradiate the product placed on the stage with ions or electromagnetic waves to neutralize the product.

[0011] The device may also include a transport mechanism that is arranged outside the product in a planar view and that transports the foreign matter floating near the sound field surface to the outside of the product in a planar view.

[0012] The semiconductor device manufacturing apparatus disclosed in this specification is a semiconductor device manufacturing apparatus that manufactures a semiconductor device by mounting a chip on a substrate, and is characterized in that it is equipped with the above-mentioned product holding device, holds the substrate as the product in the product holding device, and further includes a bonding tool that holds the chip.

[0013] In this case, the substrate may be held as the product by the product holding device, and in addition to the ionizer, an additional ionizer may be provided that irradiates the chip with ions or electromagnetic waves to neutralize the chip.

[0014] Furthermore, the product holding method disclosed in this specification is characterized in that it uses an ionizer to neutralize at least one of the product placed on a stage and the space surrounding the product, and then applies ultrasonic vibrations to the product in the neutralized state, thereby generating a sound field on the surface of the product that falling foreign objects cannot enter.

[0015] According to the technology disclosed in this specification, it is possible to more reliably prevent foreign matter from adhering to a product.

[0016] It is a schematic diagram showing the configuration of a manufacturing apparatus. It is a schematic diagram showing the state of removing foreign matter adhering to a product. It is a schematic diagram showing the state of the surface of a product. It is a schematic diagram showing the state of the surface of a product when static elimination is not performed. It is a table showing the results of an experiment for confirming the effect of removing foreign matter. It is a flowchart showing an example of a manufacturing process of a semiconductor device. It is a schematic diagram showing the configuration of another manufacturing apparatus.

[0017] The configuration of a manufacturing apparatus 10 having a holding device 30 will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing the configuration of the manufacturing apparatus 10. The manufacturing apparatus 10 manufactures a semiconductor device by mounting one or more chips 104 on a substrate 102. The manufacturing apparatus 10 has a bonding head 12, a holding device 30, and a controller 22 that controls the driving of these. The bonding head 12 and the holding device 30 are disposed in a closed space inside a chamber 18. The chamber 18 is provided with a fan filter unit (hereinafter referred to as "FFU") 20 to keep the air therein clean. The FFU 20 is a unit that combines a fan that sends air into the chamber 18 and a filter that removes foreign matter from the air.

[0018] The bonding head 12 bonds the chip 104 to the substrate 102. In this bonding, electrodes on the bottom surface of the chip 104 are joined to electrodes on the top surface of the substrate 102, resulting in an electrical connection. In this example, the properties of metal atoms are utilized to bond the electrodes together at room temperature. However, it goes without saying that bonding is not limited to room temperature bonding, and other forms of bonding may also be used. For example, the chip 104 may be heated to weld the electrodes together.

[0019] The bonding head 12 moves horizontally and vertically. The bonding head 12 also has a bonding tool 14 that suction-holds the chip 104. When bonding the chip 104 to a target surface, the chip 104 held by the bonding tool 14 is brought into contact with the substrate 102 and bonded at room temperature.

[0020] The bonding head 12 further has a positioning camera 16 for capturing an image of the substrate 102. A controller 22 (described later) identifies the position of the bonding head 12 relative to the substrate 102 based on the image captured by the positioning camera 16, and positions the bonding head 12.

[0021] The holding device 30 holds a product 100 in the middle of manufacture, specifically, a substrate 102. As described above, one or more chips 104 are bonded to the upper surface of the substrate 102. The holding device 30 has a stage 32. The substrate 102 is placed on the upper surface of this stage 32. The stage 32 also has a suction hole 34 formed therein, which communicates with the upper surface. A suction pump 36 is connected to the suction hole 34, and when the suction pump 36 is driven, the substrate 102 is suction-held to the stage 32.

[0022] The holding device 30 of this example further includes a vibration element 38 and ionizers 60a and 60b. The vibration element 38 functions as a vibration source that applies ultrasonic vibrations to the product 100 via the stage 32. A plurality of such vibration elements 38 are provided, for example, on the bottom surface of the stage 32. The plurality of vibration elements 38 may be driven simultaneously in synchronization with one another, or may be driven independently of one another. Each vibration element 38 is a vibration generating source that generates longitudinal vibrations upon receiving a drive signal, which is a voltage signal. The vibration element 38 includes, for example, lead zirconate titanate (commonly known as PZT) that vibrates upon receiving an AC voltage. The vibration element 38 is a bolt-tightened Langevin type vibrator (commonly known as a BLT or BL vibrator) in which the PZT is sandwiched between metal blocks and tightened with screws (bolts) to apply pressure.

[0023] The first ionizer 60a and the second ionizer 60b respectively neutralize the substrate 102 and the surrounding space. In the following description, when there is no need to distinguish between the first ionizer 60a and the second ionizer 60b, the subscripts a and b will be omitted and they will be referred to as "ionizer 60."

[0024] The first ionizer 60a irradiates the substrate 102 with ions or electromagnetic waves to neutralize the product 100. The first ionizer 60a may be, for example, a corona discharge ionizer that irradiates ions generated by corona discharge. Alternatively, the first ionizer 60a may be an electromagnetic wave ionizer that irradiates weak X-rays or electromagnetic waves such as alpha rays, beta rays, or ultraviolet rays. Note that the configuration of the first ionizer 60a illustrated in FIG. 1 is one example. The number, position, configuration, etc. of the first ionizers 60a may be changed as appropriate.

[0025] The second ionizer 60b irradiates the space surrounding the substrate 102 with ions or electromagnetic waves to neutralize foreign matter that settles or floats in the space. Like the first ionizer 60a, the second ionizer 60b may be a corona discharge ionizer or an electromagnetic wave ionizer. The number, position, and configuration of the second ionizers 60b may also be changed as appropriate. Either the first ionizer 60a or the second ionizer 60b may be omitted.

[0026] The controller 22 controls the operation of the manufacturing apparatus 10. Specifically, it controls the movement of the bonding head 12 to bond the chip 104 to the substrate 102. In parallel with this bonding process, the controller 22 drives the vibration element 38 and the ionizer 60 to prevent foreign matter 110 from adhering to the surface of the product 100, as will be described later. The controller 22 is physically a computer having a processor and a memory.

[0027] Next, the reason for providing the vibration element 38 and the ionizer 60 in the manufacturing apparatus 10 will be explained. The chamber 18 is provided with an FFU 20, which prevents large foreign matter from entering the chamber 18. However, it is difficult to prevent the entry of minute foreign matter 110, such as particles, and minute foreign matter 110 exists within the chamber 18. Note that particles are, for example, foreign matter of 100 μm or less. Once such particles, particularly minute particles of 20 μm or less, adhere to the surface of the product 100, they are difficult to remove.

[0028] This will be explained with reference to Fig. 2. Fig. 2 is a schematic diagram showing the removal of foreign matter 110 adhering to a product 100. The foreign matter 110 adhering to the product 100 tends to remain on the surface of the product 100 due to van der Waals forces and electrostatic forces. Hereinafter, the van der Waals forces and electrostatic forces that hold the foreign matter 110 on the surface of the product 100 will be collectively referred to as "adhesion forces."

[0029] In the past, to remove such foreign matter 110, an external force such as wind was applied to the product 100. When the foreign matter 110a is relatively large, as in the case of the foreign matter 110a on the right side of FIG. 2, the area subjected to the external force also becomes large. In this case, the foreign matter 110a is separated from the product 100. On the other hand, when the foreign matter 110a is small, as in the case of the foreign matter 110b on the left side of FIG. 2, the area subjected to the external force also becomes small. In this case, the force acting on the foreign matter 110b is dominated by the adhesive force generated between the foreign matter 110b and the product 100, rather than the external force for removing the foreign matter, and the foreign matter 110b does not separate from the product 100.

[0030] In other words, if the foreign matter 110 is of a certain size, it is easy to remove it with wind or the like, but small-diameter foreign matter, known as particles, especially extremely small foreign matter of 20 μm or less, becomes difficult to remove with external force once it adheres to the product 100. Even if the foreign matter 110 itself is small, if the foreign matter 110 is present on the electrode surface, it will form a large void at the bonding surface between the electrodes. For example, the presence of a foreign matter 110 of about 10 μm can cause a void of 200 μm or more centered around the foreign matter 110 at the bonding surface. Furthermore, with the demand for further miniaturization of semiconductor devices in recent years, such voids of several hundred μm, and even foreign matter 110 of several tens of μm, are becoming a major problem.

[0031] Therefore, in this embodiment, the vibration element 38 is provided to more reliably prevent the adhesion of such foreign matter 110, particularly minute foreign matter of several tens of micrometers called particles. As described above, the vibration element 38 applies longitudinal ultrasonic vibrations to the product 100 via the stage 32. As a result, the surface of the product 100 ultrasonically vibrates in the longitudinal direction. As shown in FIG. 3 , this ultrasonic vibration creates a sound field 70 on the surface of the product 100. The sound field 70 is a compressed air film formed on the surface of the vibrating surface, an air film similar to a squeezed air film. By creating this sound field 70, most of the sinking or floating foreign matter 110 is repelled by the surface of the sound field 70 or continues to float on the surface of the sound field 70. As a result, the entry of the foreign matter 110 into the sound field 70 is effectively prevented, and the foreign matter 110 is effectively prevented from adhering to the surface of the product 100.

[0032] However, if the foreign matter 110 and the product 100 are charged, electrostatic force may cause some of the foreign matter 110 to pass through the sound field 70 and adhere to the surface of the product 100, as shown in Fig. 4. Once the foreign matter 110 adheres to the product 100 in this way, as described above, adhesive forces such as electrostatic force and van der Waals force are generated between the two, and therefore the foreign matter 110 cannot be separated from the product 100 even if ultrasonic vibrations are applied.

[0033] Therefore, in this example, an ionizer 60 is further provided. The ionizer 60 neutralizes at least one of the product 100 and the foreign matter 110, thereby effectively preventing the foreign matter 110 from entering the sound field 70 and, in turn, from adhering to the product 100. This allows the product 100 to be kept clean.

[0034] Next, the effect of applying ultrasonic vibrations will be described. Figure 5 shows the results of an experiment conducted to verify the foreign matter removal effect. In this experiment, a sample simulating a product 100 was washed and cleaned in advance and then held in a test product holding device 30. In this state, particles representing foreign matter 110 were sprayed from above the sample for a specified time. The sample surface was then imaged, and the resulting image was subjected to predetermined image processing to calculate the area ratio of the foreign matter 110 on the sample surface. This experiment was conducted eight times in total, four times with and four times without applying ultrasonic vibrations to the sample. As a result, as shown in Figure 5, the foreign matter ratio was an average of 0.85% without applying ultrasonic vibrations, while the foreign matter ratio was an average of 0.16% with applying ultrasonic vibrations. In other words, applying ultrasonic vibrations can reduce foreign matter adhesion to the sample by approximately 80% compared to when ultrasonic vibrations are not applied. Although the ionizer 60 was not used in the experiment, the proportion of foreign matter would be further reduced if the ionizer 60 were used.

[0035] Here, the vibration element 38 may be driven continuously while the manufacturing apparatus 10 is in operation, or may be driven intermittently depending on the progress of the mounting process of the chip 104. By driving the vibration element 38 continuously, adhesion of the foreign matter 110 to the surface of the product 100 can be more reliably prevented.

[0036] Alternatively, the vibration element 38 may be temporarily stopped during the positioning process for positioning the bonding head 12 relative to the substrate 102. This will be described in detail with reference to the flowchart of Fig. 6. Fig. 6 is a flowchart showing an example of a manufacturing process for a semiconductor device.

[0037] When manufacturing the product 100, i.e., a semiconductor device, first, the substrate 102 is set on the stage 32 (S10). This setting is usually performed by a dedicated substrate transport device. Once the substrate 102 is set, the controller 22 starts driving the vibration element 38 and the ionizer 60, and starts applying ultrasonic vibrations to the substrate 102 and eliminating static electricity from the substrate 102, etc. (S12). This effectively prevents foreign matter 110 from adhering to the product 100.

[0038] Next, the controller 22 moves the bonding head 12 to a chip supply source (not shown) (S14). The bonding head 12 receives a new chip 104 from the chip supply source (S16). Thereafter, the bonding head 12 moves to a position directly above the substrate 102 (S18). Thereafter, the controller 22 temporarily suspends driving of the vibration element 38 (S20) and executes a positioning process for the bonding head 12 (S22 to S28).

[0039] That is, the controller 22 causes the positioning camera 16 to capture an image of the substrate 102 while the bonding head 12 is stationary directly above the substrate 102 (S22). Based on the image obtained, the controller 22 identifies the relative position of the bonding head 12 with respect to the substrate 102 (S24), and determines whether the positioning of the bonding head 12 is appropriate based on this relative position (S26). If the relative position is inappropriate, the controller 22 fine-tunes the position of the bonding head 12 (S28) and returns to step S22. If the relative position is appropriate (Yes in S26), the controller 22 resumes driving the vibration element 38 (S30).

[0040] In this way, by temporarily suspending the vibration element 38 during the positioning process (the period from step S22 to step S28), the positioning accuracy can be improved. Furthermore, during this positioning period, the bonding head 12 does not move, or if it does move, it moves slowly and for a short period of time. Therefore, during this positioning period, foreign matter 110 is less likely to fly up and adhere to the surface of the product 100. Therefore, by temporarily halting the driving of the vibration element 38 during the positioning period, the positioning accuracy of the bonding head 12 can be improved while reducing the risk of foreign matter adhering to the product 100.

[0041] Once the bonding head 12 has been positioned appropriately, the controller 22 drives the vibration element 38 to lower the bonding head 12 and bring the chip 104 into contact with the substrate 102 (S32). Once this contact has bonded the chip 104 to the substrate 102, the controller 22 raises the bonding head 12 (S34). The same process is then repeated until the required number of chips 104 have been bonded.

[0042] The above-described process flow is merely an example and may be modified as needed. For example, in the above example, the driving of the vibration element 38 is temporarily suspended during the positioning process of the bonding head 12. However, if movement of the product 100 is undesirable, the driving of the vibration element 38 may be temporarily stopped at another timing. For example, in FIG. 6 , the step of contacting the chip 104 with the substrate 102 is illustrated as a single step S32. However, in reality, to prevent collision between the chip 104 and the substrate 102, the bonding head 12 descends in two stages. That is, the bonding head 12 descends at high speed to a predetermined reference height where the chip 104 and the substrate 102 are close to each other. After reaching the reference height, the bonding head 12 descends at a low speed while checking whether the chip 104 has landed on the substrate 102. It is desirable for the product 100 to remain stationary during this descent period (i.e., immediately before landing) and immediately after landing. Therefore, the driving of the vibration element 38 may be temporarily stopped during the periods immediately before and after the landing.

[0043] Furthermore, after bonding the chip 104 to the substrate 102, an inspection process may be performed to check the bonding accuracy. In such an inspection process, the position of the chip 104 relative to the substrate 102, etc. may be inspected. During this inspection, the driving of the vibration element 38 may also be temporarily stopped.

[0044] As described above, if the driving of the vibration element 38 is stopped even temporarily, there is a risk that the foreign matter 110 floating on the surface of the sound field 70 will fall onto the surface of the product 100. Therefore, the product holding device 30 may further include a transfer mechanism 42 and a recovery mechanism 50 that transfer the floating foreign matter 110 to the outside of the product 100 and recover it.

[0045] The configurations of the transfer mechanism 42 and the collection mechanism 50 are not particularly limited. Therefore, for example, as shown in Fig. 7 , a blower nozzle 44 may be used as the transfer mechanism 42, and a suction nozzle 52 may be used as the collection mechanism 50. In this case, the blower nozzle 44 and the suction nozzle 52 are disposed on both sides of the product 100, and the blower nozzle 44 sends foreign matter 110 toward the suction nozzle 52. The transferred foreign matter 110 is collected by the suction nozzle 52. This configuration prevents a large amount of foreign matter 110 from accumulating on the upper side of the product 100.

[0046] Alternatively, the blower nozzle 44 may not be provided, and only the suction nozzle 52 may be provided, which may be used as both the transfer mechanism 42 and the recovery mechanism 50. The transfer mechanism 42 may also transfer the foreign matter 110 using sound waves instead of airflow. For example, an ultrasonic sound source may be provided to the side of the product 100, and the foreign matter 110 may be transferred using traveling sound waves generated from the ultrasonic sound source.

[0047] Furthermore, the collection mechanism 50 is not limited to the suction nozzle 52, and may be an adhesive body. The adhesive body has an adhesive layer on its surface that captures and holds the foreign matter 110. As another embodiment, the collection mechanism 50 may collect the foreign matter 110 using van der Waals force. For example, the collection mechanism 50 may be an electrostatic precipitator having a discharge electrode and a dust collection electrode disposed downstream in the transfer direction. In either case, the transfer mechanism 42 and the collection mechanism 50 are disposed at positions that are outside the product 100 in a plan view. This configuration prevents the bonding head 12 from interfering with the transfer mechanism 42 and the collection mechanism 50. This allows the foreign matter 110 to be transferred and collected in parallel with the bonding process performed by the bonding head 12.

[0048] Furthermore, the configurations described above are merely examples, and may be modified as appropriate as long as the configuration of claim 1 is achieved. For example, only one vibration element 38 may be provided instead of multiple vibration elements. Furthermore, the vibration element 38 may be provided elsewhere, such as inside or on the side of the stage 32, rather than on the bottom surface of the stage 32. Furthermore, the vibration element 38 may vibrate at multiple frequencies rather than a single frequency. For example, some of the multiple vibration elements 38 may vibrate at a first frequency, and the other vibration elements 38 may vibrate at a second frequency. Furthermore, the ultrasonic vibration levels output by the multiple vibration elements 38 may be the same or different from each other. For example, the output level may be different for each vibration element 38, so that the approximate center of the product 100 vibrates at a stronger level than the peripheral portions.

[0049] Furthermore, while the above-described manufacturing apparatus 10 includes the first ionizer 60a and the second ionizer 60b, the manufacturing apparatus 10 may further include an additional ionizer 66 for neutralizing the chip 104, as shown in FIG. 7 . This configuration effectively prevents foreign matter 110 from adhering to the chip 104. Furthermore, the above-described description has been given using a manufacturing apparatus that bonds the chip 104 to the substrate 102 as an example. However, the above-described holding device 30 may be incorporated into other devices, not limited to the above-described manufacturing apparatus 10. For example, the holding device 30 may be used as a device for holding a glass substrate in the process of manufacturing a flat panel display. Furthermore, the holding device 30 may be incorporated into other devices, not limited to the manufacturing apparatus 10, such as an inspection device that inspects the quality of products. Furthermore, the holding device 30 may be used independently, rather than being incorporated into other devices. For example, the holding device 30 may be used independently for temporarily storing products. Furthermore, the product held by the holding device 30 is not particularly limited, and may be a product other than a semiconductor device or a flat panel display.

[0050] 10 Manufacturing apparatus, 12 Bonding head, 14 Bonding tool, 16 Positioning camera, 18 Chamber, 22 Controller, 30 Holding device, 30 Product holding device, 32 Stage, 34 Suction hole, 36 Suction pump, 38 Vibration element, 42 Transfer mechanism, 44 Blower nozzle, 50 Recovery mechanism, 52 Suction nozzle, 60a First ionizer, 60b Second ionizer, 66 Additional ionizer, 70 Acoustic field, 100 Product, 102 Substrate, 104 Chip, 110 Foreign matter.

Claims

1. A product holding device comprising: a stage on which a product is placed; a vibration source that applies ultrasonic vibrations to the product via the stage, thereby generating a sound field on the surface of the product that inhibits the intrusion of falling foreign objects; and an ionizer that removes static electricity from at least one of the foreign objects and the product.

2. A product holding device as described in claim 1, characterized in that the ionizer irradiates ions or electromagnetic waves into the space surrounding the product to neutralize the foreign matter floating in the space.

3. A product holding device as described in claim 1, characterized in that the ionizer irradiates the product placed on the stage with ions or electromagnetic waves to neutralize the charge on the product.

4. A product holding device as described in claim 1, characterized in that it is equipped with a transfer mechanism that is positioned outside the product in a planar view and that transfers the foreign matter floating near the sound field surface to the outside of the product in a planar view.

5. A semiconductor device manufacturing apparatus for manufacturing a semiconductor device by mounting a chip on a substrate, comprising: a product holding device according to any one of claims 1 to 4; the substrate is held as the product by the product holding device; and the semiconductor device manufacturing apparatus further comprises a bonding tool for holding the chip.

6. A semiconductor device manufacturing apparatus as claimed in claim 5, characterized in that the substrate is held as the product by the product holding device, and in addition to the ionizer, an additional ionizer is provided which irradiates the chip with ions or electromagnetic waves to neutralize the chip.

7. A product holding method comprising the steps of: de-electrifying at least one of a product placed on a stage and the space surrounding the product with an ionizer; and applying ultrasonic vibrations to the product in the de-electrified state, thereby generating a sound field on the surface of the product that falling foreign objects cannot enter.

Images