JP2011119590A - Dispensing device and dispensing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dispensing device capable of being constituted of an inexpensive chamber without using a chamber having high rigidity, and shortening takt time, and a dispensing method. <P>SOLUTION: The dispensing device and the dispensing method are provided, and the device includes an imaging camera capable of imaging a chip on a substrate placed on a movable stage in a chamber; a storage means for storing history of a change in chip position until the pressure in the chamber prospectively imaged by the imaging camera, comes to a set reduced pressure; and an operating means for calculating a movement position of the chip when the pressure in the chamber comes to a set reduced pressure based on the history of a change in chip position stored in the storage means and a pressure in the chamber at the time of imaging, after the imaging camera has imaged a plurality of chips sequentially, on the way for the chamber to be reduced to the set reduced pressure. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a dispensing apparatus and a dispensing method. More specifically, the present invention relates to an apparatus and method for filling an underfill agent under reduced pressure in a gap between a substrate and a chip mounted on the substrate.

  FIG. 7 is a schematic view showing an example of a conventional dispensing apparatus. As shown in FIG. 7, the conventional dispensing apparatus 400 includes a chamber 520, a decompression unit 460, a substrate stage 710, a camera 720, a dispenser 730, a control device 90, and the like.

  A basic operation of the dispensing apparatus 400 will be described. It is assumed that the substrate K on which the chip C is mounted is placed and held on the substrate stage 710. The inside of the chamber 520 is decompressed by the decompression means 460. After the chamber 520 reaches the set pressure and stabilizes, the camera 720 reads the appearance of the chip C or the alignment mark on the substrate K and sends the image data to the control device 90. The control device 90 calculates the position information of the chip C from the read image data. Based on the position information, the control device 90 drives the substrate stage 710 in the X and Y directions so that the dispenser 730 can fill the optimal filling position with the underfill agent. Perform alignment. After alignment, the dispenser 730 is driven downward in the Z direction and discharges an underfill agent. The substrate stage 710 is moved in the X and Y directions, and an underfill agent is discharged around the chip C. The underfill agent discharged around the chip by the dispenser 730 enters between the chip C and the substrate K. When the discharge of the underfill agent is completed, the void inside the underfill agent is eliminated by opening the chamber 520 to the atmosphere (see Patent Document 1 below).

  In such a dispensing apparatus 400, the camera 720 is generally installed outside the chamber 520 and is configured to take an image from the outside of the chamber 520 through, for example, a transparent window. The reason is that when the camera 720 is installed in the chamber 520, various means for making the camera 720 vacuum-proof are necessary, and the apparatus configuration is crowded and the cost is high. In addition, the imaging by the camera 720 is performed after the inside of the chamber 520 reaches the set pressure and stabilizes. The reason is to eliminate the adverse effect that the position of the substrate stage 710 holding the substrate K shifts due to the deformation of the chamber 520 itself accompanying the decompression in the chamber 520. If the correction amount is calculated based on the appearance of the chip C imaged at atmospheric pressure or the alignment mark image of the substrate K, and the position of the substrate stage 710 is controlled while the set pressure is reduced based on the correction amount. The amount of deformation of the chamber 520 due to the reduced pressure is generated between the chip C and the dispenser 730, and accurate dispensing (filling) cannot be performed.

JP 2007-141935 A

  In the conventional dispensing apparatus 400, after the decompression is sufficiently stabilized, the plurality of chips C mounted on the substrate K are imaged by the camera 720, and then the nozzle position of the dispenser 730 and the plurality of chips C are aligned. As the number of chips C mounted on the substrate K increases, the number of times of imaging and alignment increases. Therefore, the tact time required for filling becomes long. In order to reduce the influence of the deformation amount of the chamber 520 due to the reduced pressure, a highly rigid chamber may be used. In that case, the apparatus cost increases.

  The present invention has been made in view of such a problem, and provides a dispensing apparatus and a dispensing method that can be configured with an inexpensive chamber without using a highly rigid chamber and can reduce the tact time. For the purpose.

In order to solve the above problems, the invention described in claim 1
The dispensing apparatus includes a chamber that makes the ambient atmosphere of the substrate on which the chip is mounted a preset decompression condition, and a dispenser that fills a gap between the substrate and the chip with an underfill agent provided in the chamber. And
An imaging camera capable of imaging a chip on a substrate placed on a movable stage in the chamber;
Storage means for storing a history of changes in the position of the chip until the pressure of the chamber reaches a set pressure reduction imaged in advance by the imaging camera;
While the chamber is being depressurized to the set depressurization, a plurality of chips are sequentially picked up by the imaging camera, and when the set depressurization is reached from the history of changes in the pressure in the chamber and the position stored in the storage means at the time of image pickup And a computing device for calculating a moving position of the chip.

The invention described in claim 2
In the invention of claim 1,
The imaging apparatus is a dispensing apparatus that is an imaging camera capable of imaging a chip on a substrate placed on a movable stage in the chamber from the outside of the chamber through a transparent window provided in the chamber.

The invention according to claim 3
A dispensing method in which an underfill agent is filled with a dispenser in a gap between a substrate and a chip mounted on the substrate after the chamber is set to a reduced pressure state,
Imaging a chip on a substrate in the chamber;
Storing in the storage means a history of changes in the position of the chip taken by the imaging camera until the pressure in the chamber reaches a set pressure reduction;
Based on the history of the change in the position of the chip stored in the storage means, calculating the movement position of the chip when the set pressure is reached while the chamber is being reduced to the set value pressure;
After reaching the set pressure reduction, filling the gap between the chip and the substrate with the underfill agent using a dispenser based on the calculated chip movement position;
A dispensing method characterized by comprising:

The invention according to claim 4
In the invention of claim 3,
The step of imaging the chip is a dispensing method in which the chip on the substrate in the chamber is imaged from the outside of the chamber through a transparent window provided in the chamber.

  According to the first and third aspects of the present invention, the positions of the plurality of chips are image-recognized during decompression, and the nozzle positions of the dispensers are aligned based on the previously stored history of changes in the positions of the chips. Therefore, the underfill agent filling operation can be performed in advance as compared with the case where imaging is performed after the inside of the chamber reaches the set pressure reduction and stabilizes. Therefore, the tact time of the apparatus can be shortened. In addition, since the conventional rigid chamber can be used, the apparatus cost can be reduced.

  According to invention of Claim 2 and 4, an imaging camera images the chip | tip on the board | substrate mounted in the movable stage in a chamber from the outside of a chamber through the transparent window provided in the chamber. Therefore, the apparatus can be configured with an inexpensive imaging camera.

It is a front view of the mounting system provided with the dispensing apparatus which concerns on this invention. It is a front view of the dispensing apparatus which concerns on this invention. It is a flowchart which shows the outline | summary of the operation | movement procedure of a mounting system. It is a figure explaining the movement position at the time of imaging a dummy chip with a camera. It is a graph which shows the data of the change of the position of a chip | tip. It is a flowchart which shows the operation | movement procedure of position alignment of the dispensing nozzle and chip | tip which concerns on this invention. It is the schematic which shows an example of the conventional dispensing apparatus.

  Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a front view of a mounting system equipped with a dispensing apparatus according to the present invention, FIG. 2 is a front view of the dispensing apparatus according to the present invention, and FIG. 3 is a diagram showing learning data. 1 and 2, the three axes of the orthogonal coordinate system are X, Y, and Z, the horizontal direction of the paper surface is the X direction, the direction orthogonal to the paper surface is the Y direction, the vertical direction is the Z direction, and the rotational direction around the Z axis is θ. The direction.

  As shown in FIG. 1, the mounting system 1 includes a substrate loader 2, a chip mounting device 3, a dispensing device 4, and a substrate unloader 8 in this order, and includes a control device 9. Although not shown in the drawings from the substrate loader 2 to the substrate unloader 8, a substrate transfer means for transferring the substrate K along the transfer path V is provided. This substrate transfer means is configured by a robot that holds the substrate K and has an extendable arm, or a rail member with a roller that is configured to be able to run the substrate K.

  The substrate loader 2 is a device that sequentially supplies the substrates K to the chip mounting device 3, and includes an oven 22 that can keep the substrates K warm together with the substrate magazine 21 that can store a plurality of substrates K, and a standby for waiting the substrates K. A stage 23 is provided. A heater for keeping the substrate K at an appropriate temperature is embedded in the standby stage 23.

  The chip mounting device 3 is a device that mounts the chip C on the substrate K supplied from the substrate loader 2. The chip mounting device 3 fixes and holds the substrate K in a predetermined position and can be driven in each of the X, Y, and θ directions. A chip stocker 32 for stocking the chip C to be mounted with its bump forming surface facing upward, and a chip reversing section for taking out the chip C from the chip stocker 32 by vacuum suction and inverting the chip C so that the bump forming surface faces downward 33, the two-field camera 34 configured to be able to simultaneously acquire the position information of the upper chip C and the lower substrate K, and the non-bump-formed surface of the chip C reversed by the chip reversing unit 33 And a bonding head 35 for mounting and pressing the chip C on the substrate K while holding. A heater for heating and keeping the substrate K at an appropriate temperature is embedded in the movable stage 31.

  The dispensing device 4 is a device that fills the gap between the substrate K and the chip C mounted on the substrate K with an underfill agent. As shown in FIG. 2, the chamber 52, the substrate stage 71, the camera 72, the pressure A sensor 75, a dispenser 73, a vacuum pump 46, and the like are provided.

  The chamber 52 includes a first gate valve 42 and a second gate valve 43 provided so as to be openable and closable. In addition, an open valve 47 is connected to the vacuum pump 46 via a pipe and an open / close valve 62, and the inside is opened to the atmosphere. A transparent window 54 is provided on the upper surface of the chamber 52 to enable the camera 72 to image the inside of the chamber 52.

  The substrate stage 71 is configured to be able to fix and hold a substrate K to be filled with an underfill agent (that is, the substrate K on which the chip C is mounted). The holding surface 71 </ b> H is provided with a large number of fine holes for holding the substrate K by vacuum suction, and these fine holes are connected to the vacuum pump 46. Further, the stage drive unit 74 is configured to be driven in the X and Y directions. Inside the substrate stage 71, a heater is embedded to heat and keep the substrate K fixed and held at an appropriate temperature.

  The camera 72 is configured to be able to transmit image data obtained by imaging to the control device 9 and is supported from the outside of the chamber 52 through the transparent window 54 so as not to be affected by deformation due to the internal pressure of the chamber 52. 52, the chip C on the substrate K is installed at a position where it can be imaged. The pressure sensor 75 is configured to measure the pressure in the chamber 52 and transmit the measured value to the control device 9. The camera 72 may be provided inside the chamber 52 as long as the relative positional relationship with the substrate stage 71 is a constant relationship even if deformation due to the internal pressure of the chamber 52 occurs.

  The dispenser 73 includes a discharge nozzle 73N that discharges an underfill agent, and can be driven in the Z direction. The dispenser 73 is connected to the first storage part 66 and the second storage part 67 via the check valve 69, the pipe 68 and the three-way valve 65. The 1st storage part 66 and the 2nd storage part 67 are comprised by the syringe container which can store a predetermined amount of underfill agents, respectively. The pipe 68 is connected to the vacuum pump 46 via the open / close valve 64.

  Returning to FIG. 1, the substrate unloader 8 is a device for sequentially taking out the substrates K that have been filled with the underfill agent from the dispensing device 4, and similarly to the substrate loader 2, a substrate magazine 81 that can accommodate a plurality of substrates K. And an oven 82 that can keep the substrate K warm.

  The control device 9 includes an input / output device such as a touch panel, appropriate hardware mainly including a memory chip and a microprocessor, a hard disk device incorporating a computer program for operating the hardware, and data communication with each component. The mounting system 1 is configured to send a command signal for performing a series of operations to each component. A part of the series of operations may be performed by a PLC (programmable logic controller).

  The control device 9 includes a storage unit 91 and a calculation unit 92. The storage unit 91 stores a program for controlling the entire mounting system 1, a pressure in a chamber 52 described later, and strain data of the substrate stage 71. The calculation unit 92 can calculate the movement position of the chip C based on the strain data stored in the storage unit 91 and the pressure in the chamber 52.

  Next, the operation of the mounting system 1 configured as described above will be described with reference to FIGS. 3 is a flowchart showing an outline of the operation procedure of the mounting system 1, FIG. 4 is a movement state of the dummy chip C due to the pressure in the chamber 52, FIG. 5 is data on a change in the position of the chip C, and FIG. 73 is a diagram for explaining a flowchart showing an operation procedure for positioning 73 and chip C; FIG.

  As shown in FIG. 3, the operation of the mounting system 1 is performed in the order of a learning data collection step S0, an underfill agent supply step S1, a substrate transfer step S2, a chip mounting step S3, a dispensing step S4, and a substrate unloading step S5.

  In the following description, the initial state of the dispensing apparatus 4 is the following state. That is, both the first gate valve 42 and the second gate valve 43 are closed. The release valve 47 is closed. Further, a sufficient amount of underfill agent is stored in the first storage unit 66 and the second storage unit 67, and the on-off valve 64 is closed.

  First, the learning data collection step S0 in FIG. 3 will be described. First, the dummy substrate Kd on which the dummy chip Cd is mounted is loaded into the chamber 52 by opening the first gate valve 42 and placed on the substrate stage 71. The first gate valve 42 is closed, the vacuum pump 46 is operated, and the open / close valve 62 is opened. The pressure in the chamber 52 is reduced until the set pressure PS is reached. While the atmospheric pressure is changed to the set pressure PS, the position of the dummy chip Cd on the dummy substrate Kd is observed using the camera 72. The substrate stage 71 of the chamber 52 is distorted as the pressure is reduced. Due to the distortion, the dummy chip Cd on the dummy substrate Kd placed and held on the substrate stage 71 moves as shown in FIG. In FIG. 4, (A) shows the respective states of the chamber 52 in the atmospheric pressure state, (B) in the middle of pressure reduction, and (C) in the set pressure PS. FIG. 5 shows the movement of the corner D0 of the dummy chip Cd shown in FIG. 4 divided into the X direction, the Y direction, and the θ direction. The θ direction is obtained, for example, from the inclination of the straight line connecting the two corner points D0 and D1 of the dummy chip Cd and the X axis. In FIG. 5, the horizontal axis represents the pressure of the chamber 52, and the vertical axis represents the history of changes in the X direction, the Y direction, and the θ direction. When the set pressure PS is reached, the movement position in the X direction is xs, the movement position in the Y direction is ys, and the movement position in the θ direction is θs. The history of changes in the X direction, Y direction, and θ direction of the dummy chip Cd at each pressure is stored in the storage unit 91 as learning data G.

  When the chamber 52 is depressurized to the set pressure PS, the vacuum pump 46 is stopped, the open / close valve 62 is closed, the open / close valve 47 is opened, and the chamber 52 is returned to atmospheric pressure. When the chamber 52 returns to atmospheric pressure, the second gate valve 43 is opened, and the dummy substrate Kd placed and held on the substrate stage 71 is taken out. Thus, the learning data collection step S0 is completed.

  Next, the underfill agent supply operation in step S1 of FIG. 3 is performed. The three-way valve 65 is set on the first storage part 66 side or the second storage part 67 side, and the underfill agent is supplied to the dispenser 73 via the pipe 68.

  Next, the substrate transfer operation in step S2 of FIG. 3 is performed. Each substrate K stocked in the substrate magazine 21 is kept at a predetermined constant temperature in the oven 22. The substrate transfer means supplies each substrate K stocked in the substrate magazine 21 to the chip mounting apparatus 3 one by one through the standby stage 23.

  Next, the chip mounting operation in step S3 in FIG. 3 is performed. In the chip mounting device 3, the chip reversing unit 33 is driven in the X, Y, and Z directions, and is taken out by vacuum-sucking the bump forming surface of the chip C stocked in the chip stocker 32. Thereafter, the chip C is reversed so that the bump forming surface faces downward by being rotated around the horizontal axis J1. The bonding head 35 is driven in the X, Y, and Z directions to receive the inverted chip C from the chip reversing unit 33 by vacuum suction. Then, the two-field camera 34 reads the positions of the chip C and the substrate K, and based on the position information, the movable stage 31 is driven in each of the X, Y, and θ directions to align the chip C and the substrate K (alignment). )I do. Thereafter, the bonding head 35 is driven downward in the Z direction, and the chip C held by vacuum suction is mounted on the mounting location on the substrate K and is heated and pressurized. The same chip mounting operation is repeated for the chip C at all chip mounting positions on the substrate K.

  Next, the dispensing operation in step S4 in FIG. 3 is performed. Details of step S4 are shown in FIG. 6, and the dispensing operation will be described below based on FIG. In the dispensing apparatus 4, the first gate valve 42 is opened (step S 41), and the substrate K on which the chip C is mounted by the chip mounting apparatus 3 is carried into the chamber 52 by the substrate transfer means and placed on the substrate stage 71. It is held (step S42). When the substrate K is carried into the chamber 52, the first gate valve 42 is closed (step S43). Further, the release valve 47 is closed.

  The on-off valve 62 is opened until the inside of the chamber 52 reaches the set pressure PS. Thereby, the pressure in the chamber 52 is gradually reduced (step S44).

  The following dispensing operation is performed on a plurality of chips C mounted on the substrate K. Therefore, in the flowchart of FIG. 6, in order to clarify the order of the chips C, Cn is denoted and n is 1, 2, 3 ... Are substituted to represent chips C1, C2, C3,.

  First, in order to calculate the position information of the chip C1, 1 is entered in n (step S45). Next, the stage drive unit 74 is operated, the chip Cn is disposed below the transparent window 54, and the chip Cn is imaged by the camera 72 (step S46).

  Next, the pressure in the chamber 52 is measured using the pressure sensor 75 (step S47). The imaging data of the chip Cn and the pressure data of the chamber 52 are sent to the control device 9.

  The control device 9 calculates the moving position of the chip Cn when the chamber 52 reaches the set pressure PS from the received image recognition data and pressure data and the learning data G measured in advance (step S47). ).

  For example, when the chip C1 is image-recognized and the measurement pressure is P1, the movement position is calculated as follows. First, from the learning data G in FIG. 5, when the dummy chip Cd is at the pressure P1, the movement position x1 in the X direction, the movement position y1 in the Y direction, and the movement position θ1 in the θ direction are obtained. In the case of the dummy chip Cd, when the pressure decreases and reaches the set pressure PS after this state, the movement position in the X direction is xs, the movement position in the Y direction is ys, and the movement position in the θ direction is θs. Therefore, the amount of movement from the measured data P1 to the set pressure PS is determined in the X, Y, and θ directions from the learning data measured with the dummy chip Cd. The movement amount Δx1 in the X direction is obtained as a difference between xs and x1, the movement amount Δy1 in the Y direction is obtained as a difference between ys and y1, and the movement amount in the θ direction is obtained as a difference between θs and θ1. When the chip C1 reaches the set pressure PS from the measurement pressure P1, the movement amount in the X direction is Δx1, the movement amount in the Y direction is Δy1, and the movement amount in the θ direction is Δθ1. Next, Δx1, Δy1 and Δθ1 are added to the coordinates where the chip C1 is image-recognized, and the movement position of the chip C1 when the set pressure PS is reached is obtained. The obtained movement position of the chip C1 is stored in the storage unit 91.

  Next, since the change in the position generated in the dummy chip Cd also occurs in each chip C1, C2,..., The movement position is calculated for all the chips C mounted on the substrate K. If it is not completed, n is added (n = n + 1), and the process returns to step S46 (step S50). A plurality of chips C are mounted on the substrate K. In order to recognize the target chip Cn with the camera 72, the stage drive unit 74 is driven to move the substrate stage 71. Meanwhile, the pressure in the chamber 52 continues to be reduced. The amount of movement when the set pressure PS is reached from the movement position corresponding to each pressure is obtained. In FIG. 5, the pressure in the chamber 52 when the chip Cn is image-recognized is represented as Pn.

  Even after the pressure in the chamber 52 reaches the set pressure PS, the image recognition of the chip C on the substrate K is continued until the image recognition of all the mounted chips C is completed.

  The chip C mounted on the substrate K is not always mounted at the regular position. There is a slight deviation from chip to chip. However, in the present invention, since all the chips C are image-recognized and the movement position when the set pressure PS is reached is obtained, the position of the discharge nozzle 73N of the dispenser 73 can be accurately positioned on all these chips C. It becomes like this. Further, since the image recognition of the chip C is started in the middle of the pressure reduction and the moving position when the set pressure PS is reached is obtained, compared with the conventional method of starting the image recognition of the chip C after the set pressure PS is reached. The filling operation of the underfill agent can be started in a short time. Therefore, the tact time of the apparatus can be shortened.

  When the calculation of the movement position is completed for all the chips C, the process proceeds to step S51 in FIG. First, 1 is substituted for n and the process starts from the chip Cn (step S51). Next, the stage drive unit 74 is operated to move the substrate stage 71, and the chip Cn is disposed below the dispenser 73. During the movement, the substrate stage 71 is moved based on the value calculated in step S48 (the value obtained by calculating the movement position when the set pressure PS is reached based on the learning data G) (step S52).

  Next, the dispenser 73 is lowered, the substrate stage 710 is moved in the X and Y directions around the chip Cn, the underfill agent is discharged from the discharge nozzle 73N, and the gap between the chip Cn and the substrate K is filled (step S53).

  Next, it is checked whether or not all the mounted chips C are filled with the underfill agent (step S54). If not completed, n is added (n = n + 1), and the process returns to step S52 (step S55).

  When filling of all the mounted chips C with the underfill agent is completed, the release valve 47 is opened to open the chamber 52 to the atmosphere (step S56). Next, the second gate valve 43 is opened (step S57), and the substrate K is unloaded from the chamber 52 (step S58).

  In this way, the movement position of the chip C can be determined based on the learning data G during the decompression operation without waiting for the inside of the chamber 52 to actually reach the set pressure PS and stabilize and then image each chip C. Therefore, the tact time from the completion of decompression to the dispensing operation for each chip C can be greatly reduced. In addition, since the conventional rigid chamber can be used, the apparatus cost can be reduced.

DESCRIPTION OF SYMBOLS 1 Mounting system 2 Substrate loader 3 Chip mounting device 4 Dispensing device 8 Substrate unloader 9 Control device 21 Substrate magazine 22 Oven 23 Standby stage 31 Movable stage 32 Chip stocker 34 Two field of view camera 35 Bonding head 42 First gate valve 43 Second gate Valve 46 Vacuum pump 47 Open valve 52 Chamber 54 Transparent window 62 Open / close valve 64 Open / close valve 65 Three-way valve 68 Pipe 69 Check valve 71 Substrate stage 72 Camera 73 Dispenser 75 Pressure sensor 81 Substrate magazine 82 Oven 90 Controller 91 Storage means 92 Arithmetic means J1 Horizontal axis 400 Dispensing device 460 Pressure reducing means 520 Chamber 710 Substrate stage 71H Holding surface 720 Camera 730 Dispenser 73N Discharge nozzle C chip Cd dummy chip K substrate Kd dummy substrate G Learning data

Claims (4)

The dispensing apparatus includes a chamber that sets the ambient atmosphere of the substrate on which the chip is mounted to a preset decompression condition, and a dispenser that fills a gap between the substrate and the chip with an underfill agent provided in the chamber. And
An imaging camera capable of imaging a chip on a substrate placed on a movable stage in the chamber;
Storage means for storing a history of changes in the position of the chip until the pressure of the chamber reaches a set pressure reduction, which is captured in advance by the imaging camera;
While the chamber is being depressurized to the set depressurization, a plurality of chips are sequentially picked up by the imaging camera, and when the set depressurization is reached from the history of changes in the pressure in the chamber and the position stored in the storage means at the time of image pickup A dispensing device comprising: a calculating means for calculating a moving position of the chip. In the invention of claim 1,
A dispensing apparatus, wherein the imaging camera is an imaging camera capable of imaging a chip on a substrate placed on a movable stage in the chamber from outside the chamber through a transparent window provided in the chamber. A dispensing method in which an underfill agent is filled with a dispenser in a gap between a substrate and a chip mounted on the substrate after the chamber is set to a reduced pressure state,
Imaging a chip on a substrate in the chamber;
Storing in the storage means a history of changes in the position of the chip taken by the imaging camera until the pressure in the chamber reaches a set pressure reduction;
Based on the history of the change in the position of the chip stored in the storage means, calculating the movement position of the chip when the set pressure is reached while the chamber is being reduced to the set value pressure;
Filling the underfill agent with a dispenser in the gap between the chip and the substrate based on the calculated chip movement position after reaching the set pressure reduction; and
A dispensing method characterized by comprising: In the invention of claim 3,
The dispensing method, wherein the step of imaging a chip is a step of imaging a chip on a substrate in the chamber from outside the chamber through a transparent window provided in the chamber.

Images