JP2013197278A - Semiconductor manufacturing apparatus - Google Patents

Abstract

A semiconductor manufacturing apparatus (die bonder) capable of detecting a fluctuation amount in a height direction of a surface to be measured with a configuration that contributes to cost reduction.
An apparatus for mounting at a predetermined position on a substrate (S), wherein a die is sucked and held at a tip, and a bonding head unit is mounted at a predetermined position on the substrate placed on a stage. 32, and before and after the mounting of the die by the bonding head unit, the position detection camera 42 that captures an image of the measurement target including the die D and the substrate S, and the operation of each unit are controlled to control In a semiconductor manufacturing apparatus (die bonder) including a control unit 4 for mounting the die at a predetermined position, the optical system of the position detection camera 42 is configured by a lens system including a non-telecentric lens.
[Selection] Figure 3

Description

  The present invention relates to a so-called semiconductor manufacturing apparatus such as a die bonder, and more particularly to a technique for improving accuracy and reliability in the bonding process.

  As an example of a semiconductor manufacturing apparatus, for example, a die (semiconductor chip) is mounted on a so-called substrate such as a wiring board or a lead frame, and a die bonder for assembling a package as a product has a bonding process for bonding on the substrate. Contains. In such a bonding process, it is necessary to bond the die accurately on the bonding surface of the substrate. Therefore, the die or the substrate (measurement target) is imaged by a camera, and the image is processed (for example, preset). Compared with the reference, etc.), positioning, and inspection are performed. In a semiconductor manufacturing apparatus including a die bonder, as an optical system of a camera for imaging in order to avoid a difference in the size of an image formed due to a change in distance between a die and a substrate to be measured. In general, a so-called telecentric lens (a condensing line is a lens parallel to the optical axis, and the size of the image does not change even when the distance to the measurement object fluctuates) is used.

  On the other hand, in the above-described die bonding step, as will be described later, so-called floating occurs due to deflection when the substrate on which the die is mounted is fixed, or the die is adsorbed by the collet and taken out from the wafer. When bonding to each other, dies may be stacked and bonded (overlapping bonding of dies), which deteriorates the quality of a product to be manufactured.

  Therefore, conventionally, for example, according to the following Patent Document 1, a detection pattern is irradiated from a tilt direction onto a surface to be measured, and the detection pattern is detected by an imaging unit from the vertical direction, thereby increasing the height direction. There is already known a die bonder that detects the amount of fluctuation and can perform high-speed processing and has high productivity.

JP 2012-38992 A

  However, according to the above-described prior art, a projector for irradiating the detection pattern from the tilt direction to the surface to be measured is required. For this reason, the manufacturing cost of the manufacturing apparatus has increased, and further, there has been a problem such as changing the arrangement of other components of the apparatus in order to secure the mounting position.

  Therefore, the present invention has been achieved in view of the above-described problems in the prior art, and specifically, without increasing the manufacturing cost, rather, it has a configuration that contributes to a reduction in cost, and thus the surface of the measurement object. It is an object of the present invention to provide a semiconductor manufacturing apparatus that can detect a fluctuation amount in the height direction.

In order to achieve the above object, according to the present invention, there is provided a semiconductor manufacturing apparatus mounted at a predetermined position on a substrate. Means for mounting the die at a position; and imaging means for imaging the measurement object including the die or / and the substrate before and after the mounting of the die by the mounting means;
In a semiconductor manufacturing apparatus comprising a control device for mounting the die at a predetermined position on the substrate by controlling the operation of each means, the imaging means includes a lens system including a non-telecentric lens The semiconductor manufacturing apparatus comprised by these is provided.

  According to the present invention, in the semiconductor manufacturing apparatus described above, the control unit determines whether the substrate is lifted from the stage or overlapped mounting of the die based on an image captured by the imaging unit. The imaging unit preferably images the recognition pattern formed on the surface of the substrate or the outer shape of the die. Furthermore, it is preferable that the control means further includes means for displaying the determination result.

  According to the above-described present invention, it is possible to detect the amount of variation in the height direction of the surface to be measured by a configuration that contributes to cost reduction without increasing the manufacturing cost. It is possible to provide a highly reliable die bonder capable of accurately and precisely bonding, ie, a semiconductor manufacturing method.

It is the conceptual diagram which looked at the die bonder which is one Embodiment which becomes this invention from the top. In the structure of the die bonder, it is a perspective view showing a schematic structure of a bonding head portion for performing a die bonding step of mounting a die on a substrate. It is a development perspective view showing composition of a position detection camera which images a substrate and a die in the above-mentioned bonding head part, and performs positioning. It is explanatory drawing explaining the imaging operation of the non-telecentric lens employ | adopted in this invention by the comparison with the imaging operation of a telecentric lens. It is a figure explaining the detail about the board | substrate (lead frame) which is a measuring object from which the image is detected with a position detection camera. It is explanatory drawing for demonstrating the floating by the bending | flexion of the said board | substrate (lead frame). It is a figure explaining the die | dye which is another measuring object from which the image is detected by a position detection camera. It is explanatory drawing explaining the detail of the overlapping mounting of the die on the board | substrate (lead frame) surface of the said die | dye.

  Hereinafter, details of embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 shows an example in which the present invention is applied to a semiconductor manufacturing apparatus, particularly a die bonder, which is an embodiment thereof. FIG. 1 is a conceptual view of the die bonder 10 as viewed from above. As is clear from the figure, the die bonder 10 is roughly divided into a wafer supply unit 1, a substrate supply / conveyance unit 5, and a die bonder. A bonding unit 3 and a control unit 4 for controlling them are provided.

  The wafer supply unit 1 includes a wafer cassette lifter 11 and a pickup device 12. The wafer cassette lifter 11 has a wafer cassette (not shown) filled with wafer rings, and sequentially supplies the wafer rings to the pickup device 12. The pick-up device 12 moves the wafer ring so that the desired die can be picked up from the wafer ring.

  The substrate supply / conveyance unit 5 includes a stack loader 51, a frame feeder 52, and an unloader 53. The stack loader 51 supplies a substrate (for example, a lead frame) to which the die is bonded to the frame feeder 52. The frame feeder 52 conveys the substrate to the unloader 53 via two processing positions on the frame feeder 52. The unloader 53 stores the transported substrate.

  The die bonding unit 3 includes a preform unit 31 and a bonding head unit 32. The preform unit 31 applies a die adhesive to the substrate conveyed by the frame feeder 52. The bonding head unit 32 picks up the die by the bonding head 41 and moves up, and moves the die to the bonding point on the frame feeder 52. Then, the bonding head unit 32 lowers the die at the bonding point, and bonds the die onto the substrate coated with the die adhesive.

  FIG. 2 is a perspective view showing a schematic configuration of the bonding head portion 32 for performing the die bonding step in the die bonder 10 described above.

  The bonding head 32 aligns the bonding head 41 that adsorbs and bonds the die D and the lead frame S as a substrate, and mounts (adheres) the picked-up die at a predetermined position on the substrate surface. A camera 42 (hereinafter simply referred to as “position detection camera”) for imaging the lead frame and the mounted die, a fixing base 43 that supports or fixes the bonding head 41 and the position detection camera 42, and a fixing base 43. It has a moving mechanism 47 that moves in the XY directions and a bonding stage (hereinafter simply referred to as “stage”) 44 that holds the lead frame S. Reference numeral 52 denotes a frame feeder that forms the substrate supply / conveyance unit 5 that conveys the lead frame S.

  The bonding head 41 includes a collet 41c that holds the die D at the tip thereof, and a two-dimensional moving mechanism 41m that moves the collet 41c up and down (moves in the Z direction) to move the collet 41c in the Y direction with respect to the fixed base 43. And have.

  Furthermore, although not shown here, the control unit 4 described above includes, for example, a control / arithmetic device including a CPU, a storage device including a RAM (main storage device) and an HDD (auxiliary storage device), a touch panel, a mouse, and an image capture. It includes a display device such as a device (chapter board), a motor control device, a liquid crystal panel, and an input / output control device including an I / O signal control device (sensor / switch control, etc.). Signals from a camera (not shown) and each part are input, and the operation of each part is controlled.

  Next, the above-described position detection camera 42, which is a feature of the present invention, will be described in detail below with reference to the attached FIG. 3 and FIG.

  First, the perspective view of FIG. 3 shows a schematic configuration of the position detection camera 42, and a specific lens configuration thereof is not shown. For example, a single or a plurality of optical lenses are combined in a cylindrical housing 421. A lens system 422 and a planar image sensor (for example, a CCD sensor, a CMOS sensor, etc.) for forming an image to be measured on the detection surface via the lens system and taking out the image as an electrical signal 423.

  That is, also in the semiconductor manufacturing apparatus according to the present invention, by detecting the image of the die D and the substrate (lead frame) S by the position detection camera 42 having the above-described configuration, each part of the above-described die bonding unit 3 is detected. Although the operation is controlled, in the present invention, in particular, the lens system 422 described above is a lens in which the condensing line is parallel to the optical axis, and the size of the image does not change even when the distance to the measurement object varies. The lens is not a telecentric lens but a non-telecentric lens (also referred to as a non-telecentric system). The non-telecentric lens referred to in the present invention is a lens with less telecentricity such as a CCTV lens or a microlens, for example. The operation of such a lens will be described below with reference to FIG. 4 while comparing with the telecentric lens. explain.

  FIG. 4A illustrates the imaging operation of the non-telecentric lens employed in the present invention, while FIG. 4B illustrates the imaging operation of the telecentric lens for comparison.

  As shown in FIG. 4B, in the position detection camera 42 using a telecentric lens (telecentric system) as an optical system, an image to be measured is formed on a planar image sensor 423. Here, for the sake of explanation, measurement objects having a circular outer shape and measurement objects having a square outer shape are respectively located at different positions from the camera (more specifically, the lens system 422). Each is shown. As is apparent from the figure, in the telecentric position detection camera 42, the measurement target is imaged at an equal magnification on the image sensor 423 regardless of the distance from the camera. That is, the size of the obtained image does not change.

  On the other hand, according to the non-telecentric lens, as shown in FIG. 4A, the measurement object is imaged at an unequal magnification on the image sensor 423. That is, the larger the distance from the camera, the smaller the obtained image, and the smaller the distance, the larger the obtained image.

  Therefore, in the present invention, the position detection camera 42 including the above-described non-telecentric lens is employed as the optical system. That is, according to the non-telecentric position detection camera 42, it is possible to detect the floating of the substrate or the overlapping bonding of the dies already described above. In carrying out the present invention, the optical system of the position detection camera 42 described above may be a non-telecentric system. In that case, the non-telecentric lens is generally less expensive than a telecentric lens. The structure contributes to cost reduction without increasing the manufacturing cost.

  Next, details of the measurement object whose image is detected by the position detection camera 42 constituting the semiconductor manufacturing apparatus described in detail above will be described below.

  Attached FIG. 5 shows a substrate (lead frame) S that is one of the measurement targets from which an image is detected, and a die D mounted on a part of the substrate (lead frame). Furthermore, in this figure, a reference numeral “T” indicates a land (also referred to as a tab) on which one die D is mounted, and the reference numeral “P” is provided in advance on the surface of the substrate (lead frame). , “Q” is a unique recognition pattern (reference mark) used for pattern matching or the like, and is a recognition pattern provided in advance on the surface of the substrate (lead frame). (Non-unique pattern).

  The substrate (lead frame) S described above is transported from the upstream side as shown in FIG. 6A (see the arrow in the figure), and has a plurality of through holes formed on the surface above the stage 44. It is adsorbed by a negative pressure through 441, and further fixed by a clamper 442 or the like, that is, it is in close contact so as not to float. However, in particular, in recent years, the thickness of the substrate S has become increasingly thinner, and so-called deflection F is likely to occur. For example, as shown in FIG. There is a case. At this time, as shown in the figure, the substrate S is lifted from the surface of the stage 44 due to the generated deflection F, and the die D cannot be precisely mounted.

  In such a case, in the semiconductor manufacturing apparatus of the present invention described above, when the surface of the substrate (lead frame) S is imaged by the position detection camera 42, it is possible to detect the floating due to the deflection of the surface of the substrate S. Become. More specifically, for example, a unique pattern P for pattern matching previously provided on the surface of the P substrate (lead frame) and other Q images are captured by the position detection camera 42. Then, as described above, according to the non-telecentric lens provided in the position detection camera 42, the size of the obtained image changes depending on the distance from the camera. That is, on the surface of the substrate (lead frame) S, the pattern of the portion that is lifted by the deflection becomes a larger image compared to the pattern formed on the normal (not lifted) portion.

  Therefore, for example, the shape and size of the pattern formed on the measurement target are input in advance (specifically, for example, RAM (main storage device) or HDD (auxiliary storage device) constituting the control unit 4). By comparing the image of the pattern P or Q detected by the position detection camera 42 with the stored pattern, it is possible to easily detect whether or not the substrate (lead frame) S is lifted. it can. In this case, the pattern on the measurement target is preferably a unique pattern P that is provided in advance on the surface of the substrate (lead frame) and used for pattern matching or the like. It is preferable to set a threshold value in advance and determine that there is a lift when the size of the detected pattern image exceeds the threshold value.

  Further, in that case, the fact is displayed on the display device constituting the control unit 4, the device is stopped as an error, the stage is moved up and down, or suction is turned on / off repeatedly to suck the substrate again. It is also possible to do so. Such an operation can be easily executed by changing software stored in a ROM or the like in order to control the operation of the control unit 4.

  Subsequently, in FIGS. 7 and 8, the die D mounted on a part of the substrate (lead frame) S described above is picked up from the wafer ring by the pickup device 12 in the semiconductor manufacturing apparatus of the present invention. It is shown that it is moved and mounted at a desired position on the surface of the substrate (lead frame) S.

  First, FIG. 7 shows a state in which the pickup device 12 picks up a predetermined die D from among a large number of dies in the wafer ring. Here, the pickup device 12 uses a vacuum suction portion on its lower surface as a die D. By moving the die D to the suction portion, the die D is fixed to the suction portion.

  At this time, a large number of dies of the wafer ring are supplied with their lower surfaces integrally bonded onto an adhesive sheet. At this time, for example, as shown in FIG. When the die D is picked up by the bonding unit 120, the adjacent die D may be picked up together due to the adhesion of the adhesive G. At that time, as shown by the arrows in the figure, when a force is applied to the lower die D for some reason, as shown in FIGS. 8B and 8C, the two dies D overlap. The lower die is mounted on the surface of the substrate (lead frame) S in a state where the upper and lower surfaces are reversed, leading to a reduction in the reliability of the manufactured product.

  Therefore, in general, in the subsequent inspection process, the presence or absence of overlapping mounting of the die D is inspected by measuring the height of the surface of the die D mounted on the surface of the substrate (lead frame) S. . However, in the semiconductor manufacturing apparatus of the present invention, the height (detection) is detected by detecting the surface (outer shape) after the die D is mounted by the above-described position detection camera 42 using the above-described non-telecentric lens. It becomes possible to do.

  That is, when the dies D are mounted on the substrate (lead frame) S in an overlapping manner, a larger image is obtained as compared with the case where the (single) die D is normally mounted. Therefore, for example, the shape (outer shape) and the size (dimension) of the die D mounted on the substrate (lead frame) S are input in advance (specifically, for example, the RAM constituting the control unit 4). (Stored in (main storage device) or HDD (auxiliary storage device)), after mounting the die D, the position detection camera 42 detects the image of the mounted die D and compares it with the stored pattern. According to this, it is possible to easily detect the presence or absence of overlapping mounting of the die D.

  In that case, it is possible to display the fact on the display device constituting the control unit 4 and stop the device as an error. Similar to the above, this operation can be easily executed by changing software stored in a ROM or the like to control the operation of the control unit 4.

  Although the embodiment of the present invention has been described above, the present invention includes various alternatives, modifications, and variations without departing from the spirit of the present invention.

    DESCRIPTION OF SYMBOLS 1 ... Wafer supply part, 3 ... Die bonding part, 4 ... Control part, 5 ... Substrate supply and conveyance part, 10 ... Die bonder, 32 ... Bonding head part, 41 ... Bonding head, 41c ... Collet, 42 ... Position detection camera, 423 ... Image sensor, 422 ... Telecentric lens system, 423 ... Image sensor, 43 ... Fixing base, 44 ... Bonding stage (stage), 120 ... Pickup / bonding unit.

Claims (4)

A semiconductor manufacturing apparatus for mounting a die at a predetermined position on a substrate,
Means for sucking and holding the die at the tip, and mounting the die at a predetermined position on the substrate placed on the stage;
Imaging means for imaging a measurement object including the die or / and the substrate before and after the mounting of the die by the mounting means;
In a semiconductor manufacturing apparatus provided with a control device for mounting the die at a predetermined position on the substrate by controlling the operation of each means,
The imaging device is a semiconductor manufacturing apparatus characterized in that its optical system is constituted by a lens system including a non-telecentric lens.   The semiconductor manufacturing apparatus according to claim 1, wherein the control unit determines whether the substrate is lifted from a stage or overlapped mounting of the die based on an image captured by the imaging unit. Semiconductor manufacturing equipment.   3. The semiconductor manufacturing apparatus according to claim 2, wherein the imaging unit images a recognition pattern formed on a surface of the substrate or an outer shape of the die.   4. The semiconductor manufacturing apparatus according to claim 3, wherein the control means further includes means for displaying the determination result.

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