Electronic component mounting apparatus, electronic component mounting method, and electronic component manufacturing method

Abstract

To provide an electronic component mounting apparatus and an electronic component mounting method which achieve both productivity and product quality.SOLUTION: The electronic component mounting apparatus holds an electronic component and mounts it on a member to be mounted. The mounting apparatus includes a mounting head that holds an electronic component and conveys the electronic component to a member to be mounted, a first direction driving body to which the mounting head is attached and that reciprocates the mounting head in a first direction, a driving force applying unit that applies a driving force to the first direction driving body, a temperature detecting unit that detects a temperature of at least one of the mounting head and the first direction driving body at a set temperature detection timing, a displacement amount acquiring unit that acquires a positional relationship between the mounting head and the member to be mounted in the first direction based on the temperature detected by the temperature detecting unit, and a correcting unit that corrects a movement amount of the mounting head in the first direction. In a case where the positional relationship acquired by the displacement amount acquisition unit exceeds the first position threshold value, the movement amount of the mounting head in the first direction is corrected, and in a case where the positional relationship does not exceed the first position threshold value, the movement amount is not corrected.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an electronic component mounting apparatus, an electronic component mounting method, and an electronic component manufacturing method. [Background technology]

[0002] An electronic component mounting apparatus (chip mounting apparatus) generally picks up a chip at a pickup position, transports the picked-up chip to a bonding position, and bonds the chip at the bonding position.

[0003] During operation, the position (height) of the mounting head holding the chip at the pickup position and bonding position will change due to changes in the ambient temperature over time after the electronic component mounting device starts operating.

[0004] If there is such a change, there is a risk that the chip cannot be picked up accurately at the pick-up position, and the chip cannot be bonded accurately to the mounting portion at the bonding position.

[0005] That is, due to temperature changes, the Z-direction drive body (vertical drive body) supporting the mounting head expands, causing the mounting head to be positioned lower than the initial state at the bonding position or pick-up position compared to the initial state. However, the amount of descent of the mounting head when bonding from the bonding position is constant. This means that the mounting head will be lowered to a position lower than the normal position, which may cause cracks or other problems in the chip. The same is true for pick-up operations. That is, the amount of descent of the mounting head when picking up from the pick-up position is constant, and it will be lowered to a position lower than the normal position.

[0006] This reduces the accuracy of vertical movement when picking up and mounting components, lowering product quality, making it necessary to temporarily stop the component mounting device and correct the vertical movement amount according to the displacement of the mounting head.

[0007] Therefore, there is a conventional component mounting device (Patent Document 1) that is equipped with a control device that controls the descent amount correction work, which corrects the descent amount of the work head based on the results of measuring the descent amount of the work head, and a correction setting device that sets how often the component mounting work is to be performed. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-246285 Summary of the Invention [Problem to be solved by the invention]

[0009] However, correcting the amount of lowering of the work head according to the number of component mounting operations set in advance can result in the following two problems. First, if the preset correction interval is too frequent, inspections will be performed frequently even when correction is not necessary, resulting in waste. Second, if the preset correction interval is too infrequent, processing will continue for a long time without correction even when correction is necessary, resulting in a deterioration in product quality.

[0010] In view of the above, the present invention provides an electronic component mounting apparatus and an electronic component mounting method that achieve both productivity and product quality. [Means for solving the problem]

[0011] The electronic component mounting device of the present invention is an electronic component mounting device for holding an electronic component and mounting it on a mounted member, and includes: a mounting head that holds the electronic component and transports the electronic component to the mounted member; a first direction driver attached to the mounting head that reciprocates the mounting head in a first direction; and a driving force applying means that applies a driving force to the first direction driver. The mounting head includes a temperature detection means for detecting the temperature of at least one of the mounting head and the first direction driver at a set temperature detection timing, a displacement amount acquisition means for acquiring the displacement amount of the mounting head based on the temperature detected by the temperature detection means, and a correction means for correcting the movement amount of the mounting head in the first direction based on the displacement amount.

[0012] According to the electronic component mounting device of the present invention, a temperature detection timing change means is provided for reducing the interval between preset temperature detection timings, thereby reducing the need to temporarily suspend operation and adjust the amount of movement of the mounting head during operation. [Effects of the Invention]

[0013] The present invention can reduce the need to temporarily suspend operation to adjust the amount of movement of the mounting head during operation, thereby improving productivity. Furthermore, during operation (driving), the position of the mounting head can be kept within an allowable range relative to the normal position, thereby reducing the occurrence of quality defects in products. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a block diagram showing the overall configuration of a first electronic component mounting apparatus according to the present invention. [Figure 2] FIG. 2 is a simplified diagram of a main part of the electronic component mounting device. [Figure 3] FIG. 10 is a simplified diagram showing the movement of the mounting head. [Figure 4] 10A and 10B are explanatory diagrams showing the positional relationship between the mounting head and the member to be mounted at the beginning of operation and the positional relationship between the mounting head and the member to be mounted when the mounting head is misaligned; [Figure 5] FIG. 4 is a flowchart showing the basic operation of the first electronic component mounting apparatus. [Figure 6] FIG. 10 is a process diagram of a basic operation using the first electronic component mounting device. [Figure 7] FIG. 10 is a flowchart illustrating a case where a second temperature threshold value for the temperature difference is used. [Figure 8] FIG. 10 is a flowchart illustrating a case where a first temperature threshold and a second temperature threshold are used. [Figure 9] 5A and 5B are graphs showing the change in displacement amount, where FIG. 5A is a graph showing the relationship between time and displacement amount, and FIG. 5B is a graph showing the relationship between displacement amount and temperature difference. [Figure 10] FIG. 2 is a block diagram showing the overall configuration of a second electronic component mounting apparatus according to the present invention. [Figure 11] FIG. 10 is a flowchart showing the basic operation of the second electronic component mounting apparatus. [Figure 12] FIG. 10 is a process diagram of the basic operation of the second electronic component mounting apparatus. [Figure 13] FIG. 10 is a flowchart illustrating a case where a second position threshold is used. [Figure 14] FIG. 10 is a flowchart illustrating a case where a first position threshold and a second position threshold are used in a basic operation. [Figure 15] FIG. 10 is a simplified diagram of an electronic component mounting apparatus having a Z-direction displacement measuring stage. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

[0016] 1 is a block diagram showing the overall configuration of a first electronic component mounting apparatus according to an embodiment. This electronic component mounting apparatus is used to mount a mounting member, which is an electronic component, on a mountee member. Here, the electronic component is, for example, a semiconductor (semiconductor chip), but is not limited to a semiconductor chip and may be an electronic component such as a resistor element or a capacitor. The mountee member may be a printed circuit board, a flexible substrate, a lead frame, or the like.

[0017] The electronic component mounting apparatus includes a mounting head 3 that holds a mounting member (in this case, a semiconductor chip 1 (see FIG. 3)) and transports the mounting member (semiconductor chip 1) to a mounted member (in this case, a substrate 2 (see FIG. 3)), a Z-direction driver 4 to which the mounting head 3 is attached and that reciprocates the mounting head 3 in a first direction, a driving force applying means 5 that applies a driving force to the Z-direction driver 4, a temperature detecting means 6 that detects the temperature of at least one of the mounting head 3 and the Z-direction driver 4, and a displacement amount acquiring means 7 that acquires the positional relationship in the Z direction between the mounting head 3 and the mounted member (substrate 2) based on the temperature detected by the temperature detecting means 6. In this embodiment, the first direction is the Z direction, which is the vertical direction. For this reason, in this embodiment, the first direction may be referred to as the Z direction.

[0018] Specifically, an electronic component mounting device such as that shown in Fig. 2 is used. A Z-direction driver 4 is attached to a substrate (support member 11) via a guide mechanism 10, and a mounting head 3 is also attached to the lower end of this Z-direction driver 4. In this case, the mounting head 3 is equipped with a collet 12 that adsorbs the semiconductor chip 1.

[0019] The driving force applying means 5 includes a Z-axis motor (not shown) and a conversion mechanism (e.g., a ball screw mechanism) (not shown) that converts the rotational driving force of the motor into vertical movement. The guide mechanism 10 is configured with a linear guide mechanism. As shown in FIG. 2, the linear guide mechanism includes a Z-axis guide rail 15 extending in the vertical direction (Z direction) and a Z-axis slider 14 that reciprocates along the vertical direction (Z direction) relative to the Z-axis guide rail 15. The Z-direction driver 4 is connected to the Z-axis slider 14. The Z-axis slider 14 reciprocates along the vertical direction (Z direction) relative to the Z-axis guide rail 15 by the driving force applying means 5. This causes the Z-direction driver 4 to reciprocate in the vertical Z direction.

[0020] Furthermore, Z-axis guide rail 15 is supported by support member 11. Support member 11 can be reciprocated in the X direction (one horizontal direction) via X-direction driver 16, and in the Y direction (a horizontal direction perpendicular to the X direction) via Y-direction driver 17. X-direction driver 16 reciprocates in the X direction via X-direction driving force imparting means (not shown). The X-direction driving force imparting means includes an X-axis motor (not shown) and a conversion mechanism (e.g., a ball screw mechanism) (not shown) that converts the rotational driving force of this X-axis motor into reciprocating motion in the X direction. In this case, guide mechanism 18 is interposed between X-direction driver 16 and base 20. Guide mechanism 18 is a linear guide mechanism and includes an X-axis guide rail 21 that is arranged on base 20 and extends in the horizontal direction (X direction), and an X-axis slider 22 that reciprocates (slides) along the horizontal direction (X direction) relative to X-axis guide rail 21. The X-axis slider 22 reciprocates in the horizontal direction (X direction) when driven by the X-axis motor, and the X-direction driver 16 attached to the X-axis slider 22 reciprocates in the horizontal direction (X direction). This causes the Z-direction driver 4 to reciprocate in the horizontal direction (X direction).

[0021] The Y-direction driver 17 reciprocates in the Y direction via a Y-direction driving force applying means (not shown). The Y-direction driving force applying means includes a Y-axis motor (not shown) and a conversion mechanism (e.g., a ball screw mechanism) (not shown) that converts the rotational driving force of the Y-axis motor into reciprocating motion in the Y direction. In this case, a guide mechanism 23 is interposed between the X-direction driver 16 and the Y-direction driver 17. The guide mechanism 23 is formed by a linear guide mechanism and includes a Y-axis guide rail 25 attached to the X-direction driver 16 and extending horizontally (in the Y direction), and a Y-axis slider 26 fitted into the Y-axis guide rail 25. The Y-axis slider 26 is attached to the Y-direction driver 17, and the Y-axis slider 26 reciprocates in the Y direction via the Y-direction driving force applying means. Therefore, the Y-direction driver 17 reciprocates in the Y direction due to the driving force applied by the Y-direction driving force applying means.

[0022] Therefore, by performing the operation shown in FIG. 3, the electronic component mounting apparatus can pick up, for example, the chip 1 on the XYθ table and supply it onto the substrate 2, which is the member to be mounted.

[0023] That is, from pickup position P, collet 12 is moved (lowered) in the direction of arrow B, and chip 1 on the table (XYθ table) is adsorbed onto collet 12. At this time, the chip 1 to be picked up is pushed up from below by a push-up means. Next, collet 12 is raised in the direction of arrow A, and then moved horizontally in the direction of arrow E to position it above bonding position Q. Then, chip 1 is lowered in the vertical direction as shown by arrow D. Then, at the lowest point, the adsorption of chip 1 by collet 12 is released, and chip 1 is mounted. After mounting, the collet 1 is raised in the direction of arrow C by the aforementioned downward movement, and then moved horizontally in the direction of arrow F to return to pickup position P, where the next chip 1 is picked up. Thereafter, the above steps are repeated sequentially, and all chips 1 on the wafer sheet are mounted on the mounting portions (island portions) above bonding position Q.

[0024] As shown in FIG. 1, the electronic component mounting apparatus in the embodiment is provided with a conveying means 30 for conveying the mounting head 3. The conveying means 30 can be configured with the above-mentioned X-direction driver 16, the X-direction driving force applying means can be configured with the Y-direction driver 17, the Y-direction driving force applying means, etc.

[0025] As described above, this mounting apparatus mounts all chips 1 on the wafer sheet to the mounting portions (islands) on the bonding positions Q. Therefore, over time, the Z-direction driver 4 thermally expands due to heat generated by the drive motor of the driving force applying means 5. That is, at the beginning of operation, when the Z-direction driver 4 is not thermally expanded as shown by N in FIG. 4, the collet 12 descends (moves) toward the substrate 2 to a distance a. However, due to thermal expansion of the Z-direction driver 4, the collet 12 descends, as shown by N1 in FIG. 4, and the distance between the collet 12 and the substrate 2 decreases. Therefore, the collet 12 descends (moves) to a'. Therefore, it becomes necessary to correct the displacement a to a'. In this case, the displacement b due to expansion (thermal displacement) becomes aa'.

[0026] Therefore, if thermal expansion occurs in this way, it is necessary to adjust the amount of descent of the collet 12 and the Z-direction driver 4. However, when making an adjustment, the bonding operation must be temporarily stopped to make the adjustment. Furthermore, even if the adjustment is made after a temporary stop, there is a risk that the adjustment will need to be made again when the operation is resumed. In other words, all chips 1 on the wafer sheet must be mounted on the mounting portions (island portions) on bonding positions Q, and if such a temporary stop and adjustment operation is performed while bonding the chips 1, productivity will be reduced.

[0027] Therefore, in order to minimize the number of times such bonding operations are paused and improve productivity, as shown in FIG. 1, in addition to temperature detection means 6 and displacement amount acquisition means 7, temperature detection timing setting means 31A, temperature detection timing change means 32, temperature threshold setting means 33, correction means 34, and determination means 35 are provided.

[0028] The temperature detection means 6 can be a temperature detector, such as a temperature thermistor or thermocouple. A temperature thermistor is a resistor whose electrical resistance changes significantly with temperature, and this phenomenon can be used to measure temperature. Furthermore, when one end of a dissimilar metal conductor is electrically joined and a temperature difference is applied across both ends, a current is generated, which is called a thermoelectric power. By maintaining a reference junction at a constant temperature, the temperature of the hot-contact point can be determined; this dissimilar metal conductor is a thermocouple. The temperature detector is attached to the Z-direction driver 4 or the mounting head 3.

[0029] The height position (coordinates) of the mounting head 3 is measured in advance based on the temperature detected by the temperature detector, and the relationship between the temperature difference and the amount of displacement of the height position of the mounting head 3 is input in advance to the displacement amount acquisition means 7. Therefore, once the temperature of the temperature detector is input to the displacement amount acquisition means 7, the height position of the mounting head 3 can be acquired (calculated) from the relationship between the temperature difference and the amount of displacement of the height position (coordinates) of the mounting head 3. During bonding, as shown in FIG. 4, the collet 12 of the mounting head 3 is first stopped at the bonding position at a position a predetermined height higher than the mounting position on the board 2, and then the collet 12 is lowered. The height position of the mounting head 3 is the position on the bonding position before being lowered. The relationship between the temperature detected by the temperature detector and the head height position is input in advance to the displacement amount acquisition means 7. Once the temperature is detected, the head height position can be grasped (estimated), and the head height position can be determined without any calculations. However, the head height position may be calculated by calculations or the like. The relationship between the temperature detected by the temperature detector and the head height position may be determined by referring to a correlation table stored outside the device.

[0030] Incidentally, the correction means 34 corrects the amount of movement of the mounting head 3 in the first direction (Z direction), as will be described later, and the determination means 35 determines whether to correct the amount of movement of the mounting head 3 in the first direction based on the positional relationship acquired by the displacement amount acquisition means 7. In this case, as will be described later, the determination means 35 determines to correct the amount of movement of the mounting head 3 in the first direction when the positional relationship acquired by the displacement amount acquisition means 7 exceeds the first position threshold, and determines not to correct the amount of movement when the first position threshold is not exceeded.

[0031] The displacement amount acquisition means 7, temperature detection timing setting means 31A, temperature detection timing change means 32, temperature threshold setting means 33, correction means 34, and determination means 35 are controlled (computer-controlled) by a computer, processor, memory, etc. (not shown). Here, the computer is basically composed of an input means with an input function, an output means with an output function, a storage means with a storage function, a calculation means with a calculation function, and a control means with a control function. The input function is used to read information from the outside into the computer, and the read data and programs are converted into signals in a format suitable for the computer system. The output function is used to externally display calculation results and stored data. The storage means stores and saves programs, data, processing results, etc. The calculation function calculates and compares data according to program instructions. The control function interprets program instructions and issues instructions to each means, and this control function oversees all of the computer's means. Input means include a keyboard, mouse, tablet, microphone, joystick, scanner, capture board, etc. Output means include monitors, speakers, printers, etc. Storage means include memory, hard disks, CDs, CD-Rs, PDs, MOs, etc. Calculation means include CPUs, etc., and control means include CPUs and motherboards, etc.

[0032] The temperature detection timing setting means 31A is a means for inputting the timing (time) for detecting the temperature by the temperature detector. Due to thermal expansion of the drive unit during operation, the collet 12 is lowered to a position lower than the initial state, as shown at position N1 in FIG. 4, so the amount of lowering must be adjusted. For this reason, the timing (time) at which adjustment is deemed necessary is set within the operating time, and that timing (time) is input. For this reason, the temperature detection timing setting means 31 can be configured by the computer.

[0033] 9(b) is a graph showing the correlation between temperature difference and displacement, and in this mounting device, if the displacement exceeds a threshold value, it is corrected based on a table showing the correlation between the difference in detected temperature and the displacement value for each temperature detection timing. For this reason, the temperature threshold value setting means 33 sets the threshold value for this displacement value.

[0034] The correction means 34 adjusts (corrects) the amount of descent of the collet 12 on the bonding position, and adjusts (corrects) the amount of descent in the Z direction of the Z direction driver 4. In this case, the rotation speed of the drive motor of the drive force applying means 5 is controlled.

[0035] Next, an electronic component mounting method using the electronic component mounting apparatus configured as shown in FIG. 1 will be described with reference to the flowchart shown in FIG. 5. In this case, the method includes the steps shown in FIG. 6. That is, the method includes at least a temperature detection step 60 for detecting the temperature of at least one of the mounting head 3 and the Z-direction driver 4 at a set temperature detection timing, a positional relationship acquisition step 61 for acquiring the positional relationship in the first direction between the mounting head 3 and the mounted component (such as the substrate 2 in this case) based on the difference in temperature detected in the temperature detection step 60, a determination step 62 for determining whether to correct the movement amount of the mounting head in the Z direction based on the positional relationship acquired in the positional relationship acquisition step 61, and a correction step 63 for correcting the movement amount of the mounting head 3 in the first direction if it is determined in the determination step 62 that correction should be performed. In the determination step 62, if the positional relationship calculated in the positional relationship acquisition step 61 exceeds a first threshold, the determination step 62 determines to correct the movement amount of the mounting head 3 in the first direction, and if it does not exceed the first threshold, the determination step 62 determines not to correct the movement amount.

[0036] First, as shown in Fig. 5, the temperature detection timing is set (step S1), for example, every 15 minutes from the start of operation.

[0037] The next step is to set a threshold value (step S2). The threshold value in this case is a first threshold value, which is a threshold value for the length of displacement of the collet 12 of the mounting head 3 estimated based on the difference in temperature detected by the temperature detector at each set temperature detection timing. If this first threshold value is not exceeded, even if the Z-direction driver 4 thermally expands, the amount of expansion is small, and the height position of the collet 12 above the bonding position of the collet 12 does not change much from the height position of the collet 12 in the initial operation state, and therefore does not affect the bonding operation.

[0038] Note that either the setting of the temperature detection timing or the setting of the first threshold value can be performed first; that is, step S1 can be "setting the first threshold value" and step S2 can be "setting the temperature detection timing," or even "setting the temperature detection timing and the first threshold value" can be step S1.

[0039] With the temperature detection timing and the first threshold set in this manner, operation (automatic operation) is started (step S3). Here, operation refers to moving (lowering) the collet 12 in the direction of arrow B from pickup position P, as shown in FIG. 3, to adsorb the chip 1 on the table (XYθ table) to the collet 12. Next, the collet 12 is raised in the direction of arrow A, and then moved horizontally in the direction of arrow E to position it at bonding position Q. Then, the collet 12 is lowered a certain distance in the vertical direction as shown by arrow D. At the lowest point, the collet 12 releases the adsorption of the chip 1, and the chip 1 is mounted. After mounting, the collet 12 is raised in the direction of arrow C by the same amount, then moved horizontally in the direction of arrow F, and returned to pickup position P, where the next chip 1 is picked up. Thereafter, the above steps are performed sequentially, and all of the chips 1 on the wafer sheet are mounted on the mounting portions (islands) at bonding position Q.

[0040] Next, it is determined whether it is time to detect the temperature (step S5). If it is time to detect the temperature in step S5, the process proceeds to step S6 to determine whether the temperature has exceeded the first threshold. If it is not time to detect the temperature in step S5, the process waits until it is time to detect the temperature.

[0041] If the first threshold is exceeded in step S6, the process proceeds to step S7, where the movement amount is corrected. If the position of the collet 12 exceeds the first threshold, as shown in FIG. 4, the height position of the collet 12 in the initial state changes from the state indicated by N to the state indicated by N1, resulting in a difference in the movement amount. That is, the movement amount changes from a to a' (a = a' + b). b is the amount of thermal displacement, which is the amount of displacement by which the stopping position of the mounting head 3 on the bonding position changes from the collet 12 position at N to the collet 12 position at N1 due to thermal expansion of the Z-direction driver 4, etc.

[0042] Therefore, the movement amount is changed from a to a'. At this time, the bonding operation (operation) is stopped, the movement amount is adjusted, the bonding operation (operation) is resumed, and the process proceeds to step S9. Also, if the first threshold value is not exceeded in step S6, the movement amount is not corrected (step S8). Thereafter, the process proceeds to step S9 after steps S7 and S8.

[0043] In step S9, it is determined whether or not to continue operation. If operation is to be continued, operation continues and the process returns to step S5. If operation is not to be continued in step S9, the process ends (END).

[0044] The first electronic component mounting apparatus has temperature detection timing change means 32 that reduces the interval between preset correction timings, thereby reducing the need to temporarily stop operation during operation to detect the temperatures of the mounting head 3 and Z-direction driver 4 and adjust the movement amount of the mounting head 3. Moreover, by managing the temperature, the relationship between the temperature and the movement amount of the mounting head 3 can be grasped, and the position of the mounting head can be estimated from the temperature, so that adjustment of the movement amount can be performed relatively stably. In addition, the timing when adjustment of the movement amount is not performed can be determined stably.

[0045] Furthermore, during operation (driving), if the position of the mounting head 3 is displaced from the normal position outside the allowable range, it can be corrected, thereby reducing the occurrence of defective products.

[0046] Unlike the flowchart of Fig. 5, the operation shown in Fig. 7 or 8 may be performed. In Fig. 7 or 8, a second threshold is set in addition to the first threshold. Here, the second threshold is a threshold for the displacement amount of the Z axis estimated from the temperature difference between correction timings set at predetermined time intervals, i.e., between temperature detection timings.

[0047] The operation shown in FIG. 7 will be described. In this case, although not shown in this flowchart, a first temperature detection timing, a second temperature detection timing, and a second threshold value are set. Here, the first temperature detection timing and the second temperature detection timing are set consecutively. First, the temperature at the first temperature detection timing is detected (step S10). Next, the temperature at the second temperature detection timing is detected (step S11), and the temperature difference between the first temperature detection timing and the second temperature detection timing is detected in step S12. That is, the temperature difference between the first temperature detected at the first temperature detection timing and the second temperature detected at the second temperature detection timing is detected.

[0048] Thereafter, the process proceeds to step S13, where the amount of change (amount of change in temperature) is acquired, and the process proceeds to step S14. In step S14, it is determined whether the first threshold value has been exceeded. If the first threshold value has been exceeded in step S14, the process proceeds to step S15, where the movement amount of the mounting head 3 is adjusted. If the first threshold value has not been exceeded in step S14, the process proceeds to step S16, where the movement amount is not adjusted.

[0049] The reason why the movement amount is not adjusted in this way is that if the temperature difference between the temperature at the first temperature detection timing and the temperature at the second temperature detection timing does not exceed the temperature difference threshold, the thermal displacement amount b is small, there is not much difference in the bonding operation, and there is no need to adjust the movement amount.

[0050] From step S15 and step S16, the process moves to step S17, where it is determined whether or not to continue operation. If operation is to be continued, the process returns to step S10, and if operation is not to be continued, the process ends (END).

[0051] In the case of detecting the temperature difference between the previous correction timing, which is the first temperature detection timing, and the current correction timing, which is the second temperature detection timing, if there is not much difference in temperature, the difference in the amount of displacement is also small (does not exceed the first threshold), and there is no need to adjust the amount of movement in the Z direction at the current correction timing. Therefore, there is no need to stop the mounting operation to adjust the amount of movement, which can improve productivity (workability).

[0052] The operation shown in Fig. 7 will be described. In this case, although not shown in the flowchart, a first temperature detection timing, a second temperature detection timing, a first threshold value, and a correlation table between the temperature difference and the amount of displacement are set. Here, the first temperature detection timing and the second temperature detection timing are set consecutively. The first threshold value is a threshold value for the amount of displacement at which the mounting head 3 is estimated to have been displaced based on the temperature difference between the correction timings, i.e., the temperature detection timings, set at predetermined time intervals.

[0053] First, the temperature is detected at a first temperature detection timing (step S10). Next, the temperature is detected at a second temperature detection timing (step S11), and the temperature difference between the first temperature detection timing and the second temperature detection timing is detected (step S12). In step S13, the amount of displacement is obtained from a correlation table between temperature difference and amount of displacement. Thereafter, the process proceeds to step S14, where it is determined whether the first threshold value has been exceeded. If the first threshold value has been exceeded in step S14, the process proceeds to step S15, where the movement amount of the mounting head 3 is adjusted. If the displacement amount threshold value has not been exceeded in step S14, the process proceeds to step S16, where the movement amount is not adjusted. Note that steps S15 and steps S16 and thereafter will be described later.

[0054] The reason why the movement amount is not adjusted in this way is that if the displacement amount estimated from the temperature difference between the temperature at the first temperature detection timing and the temperature at the second temperature detection timing does not exceed the displacement amount threshold, the thermal displacement amount b is small and no adjustment of the movement amount is required.

[0055] FIG. 9(a) shows the relationship between the correction timing (temperature detection timing) and the amount of displacement. The horizontal axis represents the temperature detection timing for each elapsed time, and the vertical axis represents the temperature. In this case, for example, if A is the first temperature detection timing, B is the second temperature detection timing, and C is the third temperature detection timing, a displacement amount c1 occurs between the temperatures detected at the temperature detection timing A and the temperature detection timing B. If the displacement amount c1 is greater than the second threshold, the temperature detection timing change means 32 does not change the temperature detection timing, and temperature detection is performed at the temperature detection timing C. Furthermore, if the temperature detected at the temperature detection timing B is greater than the first threshold, the Z-axis movement amount of the mounting head 3 is corrected.

[0056] Next, if B is the first temperature detection timing, C is the second temperature detection timing, and D is the third temperature detection timing, a deviation c2 occurs between the temperatures detected at the temperature detection timing B and the temperature detection timing C. If the temperature detected at the temperature detection timing C is smaller than the temperature threshold, no correction is made to the Z-axis movement amount of the mounting head 3. If the deviation c2 is larger than the deviation threshold, the temperature detection timing is not changed by the temperature detection timing changing means 32, and temperature detection is performed at the set temperature detection timing D.

[0057] Next, if C is the first temperature detection timing, D is the second temperature detection timing, and E is the third temperature detection timing, a temperature difference c3 occurs between the temperature detected at C and D. If the temperature detected at D is lower than the temperature threshold, the Z-axis movement of the mounting head 3 is not corrected. If the difference c3 is lower than the difference threshold, the temperature detection timing change means changes the temperature detection timing to a lower frequency. In other words, temperature detection is not performed at the temperature detection timing E before the change. Similarly, the difference is compared with the difference threshold based on the temperature change detected at successive temperature detection timings E, F, G, H, R, etc. As can be seen from Figure 9(a), the difference tends to decrease as time passes after the start of automatic operation.

[0058] The operation in FIG. 8 will be described. In this case, although not shown in the flowchart, a first temperature detection timing, a second temperature detection timing, a temperature threshold, and a displacement threshold are set. Here, the first temperature detection timing and the second temperature detection timing are set consecutively. Steps S10 to S16 are the same as those in FIG. 7, and therefore their description is omitted. In FIG. 8, if the temperature is below the second threshold in step S18, the process proceeds to step S19. If the temperature exceeds the second threshold, the process proceeds to step S20. In step S19, the set temperature detection timing is changed. If the temperature exceeds the second threshold, the process proceeds to step S20, and the set temperature detection timing is not changed. Note that step S17 is the same as in FIG. 7, and therefore its description is omitted. That is, if the displacement is smaller than the second threshold, the temperature detection timing can be changed to a lower frequency. This eliminates the need for frequent inspections even when correction is not necessary, improving productivity. If the displacement is greater than the second threshold, the temperature detection timing is not changed and can be performed at the set frequency, preventing processing without correction when correction is required. In this case, the second threshold is a displacement amount smaller than the first threshold. Alternatively, if the displacement amount is greater than the displacement amount threshold, the temperature detection timing may be changed to a more frequent one. This allows correction when the displacement amount is large and requires correction, thereby reducing product defects caused by processing with infrequent correction intervals.

[0059] This improves the reliability of the determination as to whether or not to adjust the movement amount at the set temperature detection timing (correction timing).

[0060] 10 is a simplified block diagram of a second electronic component mounting apparatus according to an embodiment, which in this case includes the same components as the first electronic component mounting apparatus shown in FIG. 1: a mounting head 3, a Z-direction driver 4, a driving force applying means 5, a correction timing setting means 31 (position detection timing setting means 31B in this case), a conveying means 30, and a correction means 34. In addition, the apparatus includes a position detecting means 40, a position threshold setting means 41, a position detection timing changing means 42, a determining means 43, etc.

[0061] The position detection means 40 can be a height detection sensor that detects the height position of the collet 12 in the Z direction. The height detection sensor can be attached to the collet 12 or the mounted member. Contact-type sensors, such as mechanical switches like limit switches and microswitches, and non-contact sensors, such as proximity sensors, photoelectric sensors, and ultrasonic sensors, can be used. Proximity sensors are sensors that detect the approach of a target object without contact, and include high-frequency oscillation types using electromagnetic induction, magnetic types using magnets, and capacitance types using changes in electrostatic capacitance. Photoelectric sensors emit light, such as visible light or infrared light, as a signal light from a light-emitting unit, and detect the light reflected by the target object with a light-receiving unit (reflection type) or detect changes in the amount of blocked light with a light-receiving unit (transmission type / retroreflection type) to obtain an output signal. Ultrasonic sensors emit ultrasonic waves from a sensor head, receive the ultrasonic waves reflected by the target object with the sensor head, and measure the time between the emission and reception of the sound waves to detect the target's position.

[0062] The first position threshold in the position threshold setting means 41 is the threshold of the height position detection sensor, and is the height position at which fluctuations in the height position of the collet 12 due to thermal expansion are small until this first position threshold is reached, and even if bonding is performed with this fluctuation, it does not have an adverse effect on the chip 1. For this reason, the first position threshold is set in advance and this threshold is input. For this reason, the position threshold setting means 41 can be configured by the computer.

[0063] The correction means 34 corrects the amount of movement of the mounting head 3 in the first direction, and the judgment means 43 judges whether to correct the amount of movement of the mounting head 3 in the first direction based on the height position detected by the position detection means 40.If the height position detected by the position detection means 40 exceeds the first position threshold, it judges to correct the amount of movement of the mounting head 3 in the first direction, and if it does not exceed the first position threshold, it judges not to correct the amount of movement.

[0064] In this case, if the position detection means 40 (height position sensor) does not exceed (fall below) the threshold value at the set position detection timing, no correction is made at this position detection timing, so the position detection timing can be reduced. For this reason, the position detection timing change means 42 can be composed of a height position sensor, a position threshold setting means 41, etc.

[0065] Next, a mounting method (operating method) using the second electronic component mounting apparatus will be described using the flowchart of Fig. 11. In this case, as shown in Fig. 12, the method includes at least a position detection step 65 capable of detecting the height position of the mounting head 3, a determination step 66 that determines whether to correct the amount of movement of the mounting head in the first direction based on the height position detected in the position detection step 65, and a correction step 67 that corrects the amount of movement of the mounting head 3 in the first direction. In the determination step 66, if the height position detected in the position detection step exceeds a first position threshold, the determination step 66 determines to correct the amount of movement of the mounting head in the first direction, and if the height position detected in the position detection step does not exceed the first position threshold, the determination step 66 determines not to correct the amount of movement.

[0066] In this case, first, the correction timing (position detection timing) and threshold are set. That is, the position detection timing is set (step S21), the first position threshold is set (step S22), and operation is started (step S23). In this case, the first position threshold is a threshold for the height position. This position detection timing is set, for example, every 15 minutes after the start of operation.

[0067] In this case, the first position threshold is a threshold for the position (height position) in the first direction detected by the position detection means 40. As long as the height position of the collet 12 before it descends is not lower than this position, the bonding operation will not be affected even if the Z-direction driver 4 thermally expands. The height position of the collet 12 is the height position when it is transported from the pickup position to the bonding position and temporarily stopped, and as operation continues, the Z-direction driver 4 will expand due to thermal expansion. If the Z-direction driver 4 expands in this way, the position of the collet 12 will be lower than it was in the initial stage.

[0068] Note that either the setting of the position detection timing or the setting of the first position threshold may be performed first; that is, step S21 may be "setting the threshold" and step S22 may be "setting the position detection timing," or may be "setting the position detection timing and the threshold."

[0069] Operation is the operation shown in Figure 3. Operation is started, and then it is determined whether it is time to detect the position (step S24). If it is time to detect the position in step S24, the process proceeds to step S25, and if it is not time to detect the position, the process waits until it is time to detect the position. In step S25, it is determined whether the position is below the first position threshold. If it is below the first position threshold in step S25, the movement amount of the mounting head 3 is adjusted in step S26. This allows stable bonding of chips.

[0070] If the position is not below the first position threshold in step S25, the process proceeds to step S27, and the movement amount is not adjusted. In this way, whether or not the movement amount is adjusted, the process proceeds to step S28, and it is determined whether or not to continue driving. If driving is to be continued, the process returns to step S24, and if driving is not to be continued in step S28, driving is terminated.

[0071] Like the first electronic component mounting apparatus, the second electronic component mounting apparatus has a position detection timing change means 42 that reduces the interval between preset position detection timings, thereby reducing the need to temporarily suspend operation to adjust the movement amount of the mounting head 3. In particular, the second electronic component mounting apparatus can relatively stably adjust the movement amount by managing the position of the mounting head 3, and can also stably determine the timing when movement amount adjustment is not required. Meanwhile, the first electronic component mounting apparatus manages temperature, which requires prior knowledge of the temperature difference and the thermal expansion and contraction amount of the Z-direction driver 4, whereas the second electronic component mounting apparatus manages position, which eliminates the need to know the temperature difference and the thermal expansion and contraction amount of the Z-direction driver 4, resulting in superior controllability.

[0072] The second electronic component mounting apparatus can also improve productivity by reducing the need to temporarily suspend operation and adjust the movement amount of the mounting head 3. Furthermore, during operation (driving), the position of the mounting head 3 can be kept within an allowable range relative to the normal position, making it less likely that defective products will occur and preventing a decline in product quality.

[0073] Different from the flowchart of Fig. 11, the operations shown in Fig. 13 or 14 may be performed. In this case, a second position threshold different from the first position threshold and a position difference threshold are set in Fig. 13 or 14. Here, the second position threshold (position difference threshold) is a threshold for the position difference between correction timings that is set every predetermined time (every predetermined minute).

[0074] The operation shown in Fig. 13 will now be described. In this case, although not shown in this flowchart, a threshold value (second position threshold value) for changing the frequency of position detection timing is set. First, a first position, which is the position at the first position detection timing, is detected (step S30). Next, a second position, which is the position at the second position detection timing following the first position detection timing, is detected (step S31), and the position difference between the first position and the second position is detected in step S32. That is, the position difference between the position at the previous position detection timing (the position of the mounting head 3, specifically the position of the collet 12) and the position at the current position detection timing (the position of the mounting head 3, specifically the position of the collet 12) is detected.

[0075] Thereafter, the process proceeds to step S33, where it is determined whether the first position threshold has been exceeded. If the second position threshold has been exceeded in step S33, the process proceeds to step S34, where the movement amount is adjusted. If the first position threshold has not been exceeded in step S33, the process proceeds to step S35, where the movement amount is not adjusted.

[0076] The reason why the movement amount is not adjusted in this way is that if the position difference between the position at the previous correction timing and the position at the current correction timing does not exceed the second position threshold, the positional displacement amount is small, there is not much difference in the bonding operation, and there is no need to adjust the movement amount.

[0077] From step S34 and step S35, the process moves to step S36, where it is determined whether or not to continue operation. If operation is to be continued, the process returns to step S30, and if operation is not to be continued, the process ends (END).

[0078] In the case of detecting the position difference between the previous correction timing (first position detection timing) and the current correction timing (second position detection timing), if the position difference is small (does not exceed the first position threshold), there is no need to correct the movement amount in the Z direction at the current correction timing. Therefore, there is no need to stop the mounting operation to correct the movement amount, which can improve productivity (workability).

[0079] The operation in FIG. 14 is similar to steps S30 to S35 in FIG. 13. Then, in FIG. 14, the process proceeds from step S35 to step S37, and in step S37, it is determined whether the position difference acquired in step S32 exceeds the second position threshold. If the second position threshold is exceeded in step S37, the process proceeds to step S39, and the position detection timing is not changed. If the second position threshold is not reached in step S38, it is determined that the amount of change in the position of the mounting head 3 (specifically, the position of the collet 12) between the first position detection timing and the second position detection timing is small, and the process proceeds to step S38, and the position detection timing change means 42 changes the frequency of the position detection timing to a lower frequency. Note that step S36 is similar to FIG. 13, and therefore its description will be omitted. The change in the position detection timing by the position detection timing change means in step S40 may be changed to a higher frequency. In this case, the amount of change in the position of the mounting head 3 is large due to exceeding the second position threshold in step S33, and it is possible to increase the frequency of determining whether to correct the amount of movement, thereby preventing defective products from occurring due to continued production while the frequency of correcting the amount of movement is low.

[0080] By doing so, the reliability of the determination as to whether or not to adjust the movement amount at the current correction timing is improved.

[0081] Let us now consider Figure 9(a) as showing the relationship between position detection timing and position difference. The horizontal axis represents the position detection timing for each elapsed time, and the vertical axis represents the position difference, which is the amount of position displacement. In this case, for example, if A is the first position detection timing, B is the second position detection timing, and C is the third position detection timing, a position displacement amount c1 will occur between the position detection timing A and the position detection timing B. If the displacement amount c1 is greater than the second position threshold, the position detection timing change means 42 will not change the position detection timing, and position detection will be performed at the position detection timing C. Furthermore, if the temperature detected at the temperature detection timing B is greater than the first position threshold, the Z-axis movement amount of the mounting head 3 will be corrected.

[0082] Next, if B is the first position detection timing, C is the second position detection timing, and D is the third position detection timing, a displacement amount c2 occurs between the positions detected at the position detection timing B and the position detection timing C. If the position detected at the position detection timing C is greater than the first position threshold, no correction is made to the Z-axis movement amount of the mounting head 3. Then, if the displacement amount c2 is greater than the second position threshold, the position detection timing is not changed by the position detection timing change means 42, and position detection is performed at the set position detection timing D.

[0083] Next, if C is the first position detection timing, D is the second position detection timing, and E is the third position detection timing, a displacement amount c3 occurs between the positions detected at C and D. If the position detected at D is smaller than the first position threshold, the Z-axis movement amount of the mounting head 3 is not corrected. If the displacement amount c3 is smaller than the second position threshold, the position detection timing change means changes the position detection timing to a lower frequency. In other words, detection is not performed at E before the change. Similarly, the displacement amount is compared with the second position threshold based on the amount of change in position detected at successive position detection timings E, F, G, H, R, etc. As can be seen from Figure 9(a), the displacement amount (position difference) tends to decrease as time passes after the start of automatic operation.

[0084] In this case, it is preferable to set the second position threshold to a value smaller than the first position threshold. For example, it may be determined that the second position threshold is below the first position threshold if the first position threshold is not exceeded two or more times.

[0085] However, when operation begins, areas on the substrate 2 where components (chips 1) are placed and areas where they are not are created, resulting in a mixed state. In such a case, if the position (height position) of the collet 12 is detected at the bonding position Q, it may be difficult to measure the amount of displacement, or the measurement method may become complicated. However, as shown in FIG. 15, if the Z-axis displacement measurement stage 50 is installed at a location (place) different from the bonding position Q, it is less affected by the state of the substrate during production. Here, the Z-axis displacement measurement stage 50 has a flat upper surface, and the height position (predetermined height) of this flat surface is known. As shown in FIG. 15, the substrate 2 is disposed on a substrate transport unit 51, and the Z-axis displacement measurement stage 50 is also set on this substrate transport unit 51.

[0086] Incidentally, the adjustment of the displacement amount of the mounting head 3 was performed when bonding the chip, but it may also be performed when picking up the chip 1. In this way, even if the displacement amount is adjusted when picking up the chip 1, the operation is the same as adjusting the displacement amount when bonding the chip 1.

[0087] Electronic components can be manufactured using an electronic component mounting device that uses the temperature detection means 6 or an electronic component mounting device that uses the position detection means 40. That is, it is possible to manufacture products such as elements that have electronic components such as resistor elements and capacitors.

[0088] The present invention is not limited to the above-described embodiment and can be modified in various ways. It can be widely used in manufacturing methods for semiconductor devices that mount electronic components, as well as in manufacturing products that mount components such as semiconductor chips. The first temperature threshold, second temperature threshold, first position threshold, and second position threshold can be set arbitrarily, but they can be set within a range that does not interfere with the bonding operation at bonding position Q or the pick-up operation at pick-up position P. If the correction timing is too short, unnecessary judgment operations may be performed due to slight fluctuations in the position of the mounting head 3. Conversely, if the correction timing is too long, the position of the mounting head 3 should be adjusted by the correction timing. Therefore, various settings can be made depending on the heat generation amount of the drive motor of the driving force applying means used, the material of the Z-direction driver 4 used, and the like.

[0089] When using the Z-axis displacement measuring stage 50, the Z-axis displacement measuring stage 50 can be installed at any position, but if the amount of displacement of the mounting head 3 is to be adjusted when picking up the chip 1, it is preferable to install it near the pick-up position P, but it is also preferable to install it in a location that does not interfere with the pick-up operation of the collet 12. It may also be installed midway between the pick-up position P and the bonding position Q, so that the amount of displacement of the mounting head 3 when picking up and when setting to the bonding position can be adjusted.

[0090] The Z-direction driver 4 may be a device that includes a Z-axis slider that moves (reciprocates) in the Z direction upon receiving the driving force of the driving force applying means 5, and a Z-axis driven slider that moves in the Z direction following the movement of the Z-axis slider. In this case, the mounting head 3 is attached to the Z-axis driven slider. In a mounting device that includes a Z-axis slider and a Z-axis driven slider and uses a temperature detection means, it is preferable to provide a temperature detector as the temperature detection means 6 on the Z-axis slider side, which is close to the drive motor of the driving force applying means 5 and is therefore more likely to heat up, but a temperature detector may also be provided on the Z-axis driven slider side. Furthermore, in a mounting device that uses a position detection means 40, it is sufficient to detect the height position of the collet 12.

[0091] In the embodiment, the first direction is the Z direction, which is the vertical direction, but the first direction may be the X direction or Y direction in the present embodiment. [Explanation of symbols]

[0092] 3 Mounting head 4 First direction drive body (Z direction drive body) 5. Driving force applying means 6 Temperature detection means 7. Displacement acquisition means 32 Temperature detection timing change means 34 Correction means 35 Judgment means 40 Position detection means 42 Position detection timing change means 43 Judgment means 60 Temperature detection process 61 Positional relationship calculation process 62 Judgment process 63 Correction process 65 Position detection process 66 Judgment process 67 Correction process

Claims

1. An electronic component mounting apparatus for holding an electronic component and mounting it on a mounting member, a mounting head that holds the electronic component and transports the electronic component to the mounting target; a first direction driver to which the mounting head is attached and which reciprocates the mounting head in a first direction; a driving force applying means for applying a driving force to the first direction driving body; a temperature detection means for detecting the temperature of at least one of the mounting head and the first direction driver at a set temperature detection timing; a displacement amount acquiring means for acquiring a displacement amount of the mounting head based on the temperature detected by the temperature detecting means; and a correction unit that corrects the movement amount of the mounting head in the first direction based on the displacement amount.

2. The electronic component mounting device according to claim 1, characterized in that the displacement amount acquisition means acquires the displacement amount based on a temperature difference between a first temperature detected by the temperature detection means at a first temperature detection timing and a second temperature detected by the temperature detection means at a second temperature detection timing.

3. The electronic component mounting device according to claim 1, characterized in that the amount of movement of the mounting head in the first direction is corrected when the amount of displacement acquired by the displacement amount acquisition means exceeds a first threshold value, and the amount of movement is not corrected when the amount of displacement acquired does not exceed the first threshold value.

4. The temperature detection timing change unit further includes a temperature detection timing change unit, and the temperature detection unit acquires a positional displacement amount of the mounting head in the first direction from a temperature difference between a first temperature detected at a first temperature detection timing and a second temperature detected at a second temperature detection timing. The electronic component mounting device according to claim 1 , wherein the temperature detection timing is changed when the displacement amount exceeds a second threshold value.

5. 5. The electronic component mounting device according to claim 4, wherein the temperature detection timing changing means changes the set temperature detection timing to a lower frequency when the amount of displacement is smaller than the second threshold value.

6. 5. The electronic component mounting device according to claim 4, wherein the temperature detection timing changing means changes the set temperature detection timing to a higher frequency when the amount of displacement is greater than a second threshold value.

7. An electronic component mounting apparatus for holding an electronic component and mounting it on a mounting member, a mounting head that holds the electronic component and transports the electronic component to the mounting target; a first direction driver to which the mounting head is attached and which reciprocates the mounting head in a first direction; a driving force applying means for applying a driving force to the first direction driving body; a position detection means capable of detecting the position of the mounting head; a correction unit that corrects the movement amount of the mounting head in a first direction; a position detection timing change means for changing the position detection timing, obtaining a position difference from a difference between a first position detected by the position detection means at a first position detection timing and a second position detected by the position detection means at a second position detection timing; An electronic component mounting apparatus, characterized in that, when the position difference exceeds a first position threshold, the movement amount of the mounting head in the first direction is corrected.

8. a determination unit that determines whether to correct the movement amount of the mounting head in the first direction based on the position of the mounting head detected by the position detection unit, The electronic component mounting device described in claim 7, characterized in that the judgment means determines to correct the movement amount of the mounting head in the first direction when the position difference detected by the position detection means exceeds a first position threshold, and determines not to correct the movement amount when the position difference does not exceed the first position threshold.

9. 8. The electronic component mounting apparatus according to claim 7, wherein the position detection timing change means changes the position detection timing to a lower frequency when the position difference is smaller than a second position threshold value.

10. 8. The electronic component mounting apparatus according to claim 7, wherein the position detection timing changing means changes the position detection timing to a higher frequency when the position difference is greater than a second position threshold value.

11. 8. The electronic component mounting device according to claim 7, wherein if the position difference is smaller than a second position threshold, position detection is not performed at a third position detection timing set after the second position detection timing.

12. An electronic component mounting method for holding an electronic component and mounting it on a substrate using an electronic component mounting apparatus including: a mounting head that holds an electronic component and transports it to a substrate; a first direction driver that is attached to the mounting head and reciprocates the mounting head in a first direction; and driving force applying means that applies a driving force to the first direction driver, a temperature detection step of detecting the temperature of at least one of the mounting head and the first direction driver at a set temperature detection timing; a displacement amount acquiring step of acquiring a displacement amount of the mounting head based on the temperature detected in the temperature detecting step; and a correction step of correcting the movement amount of the mounting head in the first direction based on the displacement amount.

13. a mounting head that holds the electronic component and transports it to a mounting target; a first direction driver to which the mounting head is attached and which reciprocates the mounting head in a first direction; a driving force applying means for applying a driving force to the first direction driving body, and an electronic component mounting method for holding an electronic component and mounting it on a mounting target member using an electronic component mounting apparatus including the electronic component mounting apparatus, a position detection step capable of detecting the position of the mounting head; a correcting step of correcting a movement amount of the mounting head in a first direction; a position difference is obtained from a difference between a first position detected at a first position detection timing and a second position detected at a second position detection timing in the position detection step; An electronic component mounting method comprising a position detection timing changing step of changing the position detection timing when the position difference exceeds a second position threshold value.

14. 10. An electronic component manufacturing method, comprising the steps of: manufacturing an electronic component by using the electronic component mounting apparatus according to claim 1 or 7;

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