JP2020065004A - Mounting apparatus and manufacturing method of semiconductor device - Google Patents

Abstract

To provide a mounting apparatus that can appropriately heat a bonding target semiconductor chip and a manufacturing method of a semiconductor device.SOLUTION: A mounting apparatus that bonds a semiconductor chip 12 to a mounted body being a substrate 30 or other semiconductor chip 12 to manufacture a semiconductor device comprises: a stage 120 on which the substrate 30 is mounted; a mounting head 124 that is relatively movable for the stage 120, and that bonds the semiconductor chip 12 to the mounted body; and an irradiation unit 150a that has an electromagnetic wave source 132 which outputs an electromagnetic wave transmitting through the stage 120 and heating the substrate 30 or an intermediate member 140, and an adjustment mechanism which adjusts intensity distribution of the electromagnetic wave for the semiconductor chip 12. The stage 120 has a first layer 122 that is formed on an upper surface side, and heat resistance of the first layer 122 in a surface direction is larger than heat resistance in a thickness direction.SELECTED DRAWING: Figure 5

Description

  The present specification discloses a mounting apparatus for manufacturing a semiconductor device by bonding a semiconductor chip to a mounted body which is a substrate or another semiconductor chip, and a method for manufacturing the semiconductor device.

  When a semiconductor chip is bonded onto a substrate or another semiconductor chip, the semiconductor chip is usually heated and pressed by a heated mounting head. However, it is difficult to properly heat the semiconductor chip to be bonded only by the heat from the mounting head. In particular, in recent years, it has been proposed to stack and mount a plurality of semiconductor chips in order to further enhance the functionality and size of the semiconductor device. In this case, in order to reduce the mounting process time, a plurality of semiconductor chips may be stacked while being temporarily pressure-bonded, and then the plurality of semiconductor chips may be collectively pressure-bonded together. That is, there is a case in which a plurality of semiconductor chips are stacked in a temporary pressure-bonded state to form a temporary stacked body, and then the upper surface of the temporary stacked body is heated and pressed by a heating mounting head to perform final pressure bonding. In such a case, it is difficult to properly heat the lowermost semiconductor chip of the temporary stack by using only the heat from the mounting head. Therefore, conventionally, when bonding a semiconductor device, the entire stage on which the substrate is placed is heated. According to this, it is possible to heat the semiconductor chip from both upper and lower sides.

International Publication No. 2010/050209 Japanese Patent No. 3833531 Japanese Patent No. 4001341

  However, when the entire stage is heated, the semiconductor chip arranged at a position different from the bonding target (heating target) semiconductor chip also continues to be heated. As a result, heat is input to the semiconductor chip for a long time. Such a long-term heat input causes deterioration of the resin such as the semiconductor chip, in particular, a non-conductive film (Non Conductive Film) provided on the bottom surface of the semiconductor chip, and eventually the mounting quality.

  In order to avoid such a problem, it is possible to provide a heater for local heating such as a pulse heater at a plurality of locations on the stage and turn on only the heater at a required location. However, when such a heater for local heating is embedded in the stage, it is difficult to maintain the flatness of the stage, which leads to deterioration of mounting quality.

  Further, Patent Documents 1-3 disclose a technique of optically heating a substrate with light emitted from the back side of the stage. However, all of these techniques are sufficient for locally heating the substrate. Is not taken into account.

  Further, when the semiconductor chip arranged on the substrate is heated by the light emitted from the back surface side, the temperature of the peripheral portion of the semiconductor chip is expected to be lower than that of the central portion because heat diffuses to the outside air or the substrate. It Therefore, even if the semiconductor chip is uniformly irradiated with light, temperature unevenness occurs in the surface of the semiconductor chip.

  Therefore, the present specification provides a mounting apparatus that can appropriately heat a semiconductor chip to be bonded, and a method of manufacturing the semiconductor device.

  A mounting device disclosed in the present specification is a mounting device for manufacturing a semiconductor device by bonding a semiconductor chip to a substrate or a mounted object which is another semiconductor chip, wherein the substrate is directly mounted or an intermediate member is mounted. A stage having a first surface mounted via the stage and a second surface opposite to the first surface, and capable of relative movement with respect to the stage, and bonding the semiconductor chip to the mounted body The mounting head, and an irradiation unit that transmits the electromagnetic wave that heats the substrate or the intermediate member from the second surface side while passing through the stage, and the stage is formed on the first surface side. A first layer is provided, and the first layer is characterized in that the thermal resistance in the surface direction is larger than the thermal resistance in the thickness direction.

  The substrate is one in which a plurality of the semiconductor chips are thermocompression bonded, the irradiation unit, at least one of the irradiation area of the electromagnetic wave on the first surface, and the irradiation position of the electromagnetic wave on the first surface. A changing means for changing may be provided.

  Further, the mounting head includes a heater that heats and temporarily press-bonds a temporary stacked body in which the plurality of semiconductor chips are temporarily pressed and the irradiation unit heats the temporary stacked body together with the heater. You may.

  Further, the stage further has a second layer formed on the second surface side with respect to the first layer, and the first layer has a larger thermal resistance in the surface direction than the second layer. Good.

  The second layer is a solid part made of a material that can transmit the electromagnetic waves, and the first layer is a part having a plurality of grooves on the upper surface or a plurality of pores in the layer. Good.

  Further, the substrate may be a silicon wafer and may be placed directly on the stage, the electromagnetic wave may have a wavelength of 1200 nm or less, and the substrate may be locally heated by the electromagnetic wave.

  Further, the substrate is placed on the stage via the intermediate member, the electromagnetic wave is absorbed by the intermediate member, and has a wavelength not absorbed by the substrate, locally by the electromagnetic wave. The substrate may be locally heated by heat transfer from the heated intermediate member.

A method for manufacturing a semiconductor device disclosed in the present specification is a semiconductor device manufacturing method for manufacturing a semiconductor device by bonding a semiconductor chip to a mounted body that is a substrate or another semiconductor chip, and directly manufacturing the substrate. Alternatively, a mounting step of mounting the semiconductor chip on the first surface of the stage via an intermediate member, and a bonding step of bonding the semiconductor chip to the mounted body by a mounting head movable relative to the stage, In parallel with at least a part of the bonding step, an irradiation unit disposed on the opposite side of the mounting head with the stage interposed therebetween emits electromagnetic waves absorbed by the substrate or the intermediate member and transmitted through the stage. And a substrate heating step of heating the substrate or the intermediate member, and the stage is formed on the first surface side. Having a first layer which is,
The first layer is characterized in that the thermal resistance in the surface direction is larger than the thermal resistance in the thickness direction.

  The bonding step includes a temporary pressure bonding step of sequentially forming, on the plurality of positions of the substrate, a temporary stacked body in which one or more semiconductor chips are stacked while being temporarily pressure bonded by the mounting head. After the temporary pressure bonding step, heating and pressing one temporary laminated body from the upper surface thereof to perform main compression bonding of one or more of the semiconductor chips forming the temporary laminated body collectively at a plurality of positions on the substrate. In the main pressure bonding step performed in, the substrate heating step, in parallel with the process of main compression bonding the semiconductor chips in a batch, at a location corresponding to the main compression execution location of the substrate or the intermediate member, You may irradiate the said electromagnetic wave.

  According to the apparatus and method disclosed in the present specification, since the substrate is locally heated by the electromagnetic wave, the semiconductor chip to be bonded can be appropriately heated. Further, since the thermal resistance of the first layer of the stage in the surface direction is higher than the thermal resistance in the thickness direction, heat transfer to other semiconductor chips spaced apart in the surface direction is suppressed, and by extension other semiconductors. Heat input to the chip is suppressed.

It is a figure which shows the structure of a mounting apparatus. It is a figure which shows an example of a semiconductor device. It is a figure which shows an example of a board | substrate. It is a figure which shows an example of a semiconductor chip. It is a figure which shows a mode that the substrate is locally heated. It is an X section enlarged view of FIG. It is a figure which shows another example of a stage. It is a figure which shows another example of a stage. It is a figure which shows another example of a stage. It is a figure which shows another example of a stage. It is a schematic diagram which shows a heating device, and a figure which shows the intensity | strength of an electromagnetic wave. It is a schematic diagram which shows a heating device, and a figure which shows the intensity | strength of an electromagnetic wave.

  Hereinafter, a semiconductor device manufacturing method and a mounting apparatus 100 will be described with reference to the drawings. FIG. 1 is a diagram showing a configuration of the mounting apparatus 100. The mounting apparatus 100 is an apparatus for mounting the semiconductor chip 12 on the substrate 30. The mounting apparatus 100 has a particularly suitable configuration when a plurality of semiconductor chips 12 are stacked and mounted. In the following description, among the stacked bodies formed by stacking the plurality of semiconductor chips 12, those in which the plurality of semiconductor chips 12 forming the stacked body are in the temporary pressure bonding state are referred to as “temporary stacked body STt”, and The semiconductor chip 12 that is in the main pressure-bonding state is referred to as a “chip stacked body STc” to distinguish them.

  The mounting apparatus 100 includes a chip supply unit 102, a chip transport unit 104, a bonding unit 106, an irradiation unit 108, and a control unit 130 that controls driving of these. The chip supply unit 102 is a part that takes out the semiconductor chip 12 from the chip supply source and supplies it to the chip transport unit 104. The chip supply unit 102 includes a protrusion 110, a die picker 114, and a transfer head 116.

  In the chip supply unit 102, the plurality of semiconductor chips 12 are placed on the dicing tape TE. At this time, the semiconductor chip 12 is mounted in a face-up state with the bumps 18 facing upward. The protrusion 110 pushes only one semiconductor chip 12 out of the plurality of semiconductor chips 12 upward in a face-up state. The die picker 114 sucks and holds the semiconductor chip 12 pushed up by the protrusion 110 at its lower end. The die picker 114 that has received the semiconductor chip 12 rotates 180 degrees on the spot so that the bumps 18 of the semiconductor chip 12 face downward, that is, the semiconductor chip 12 is placed face down. In this state, the transfer head 116 receives the semiconductor chip 12 from the die picker 114.

  The transfer head 116 can move vertically and horizontally, and the lower end thereof can suck and hold the semiconductor chip 12. When the die picker 114 rotates 180 degrees to bring the semiconductor chip 12 into the face-down state, the transfer head 116 sucks and holds the semiconductor chip 12 at its lower end. Then, the transfer head 116 moves horizontally and vertically to move to the chip transfer unit 104.

  The chip transport unit 104 has a turntable 118 that rotates about a vertical rotation axis Ra. The transfer head 116 mounts the semiconductor chip 12 at a predetermined position on the turntable 118. When the rotary table 118 on which the semiconductor chip 12 is mounted rotates about the rotation axis Ra, the semiconductor chip 12 is transported to the bonding unit 106 located on the opposite side of the chip supply unit 102.

  The bonding unit 106 includes a stage 120 that supports the substrate 30, and a mounting head 124 that attaches the semiconductor chip 12 to the substrate 30. The stage 120 has an upper surface (first surface) on which the substrate 30 is placed and a lower surface (second surface) opposite to the first surface. Further, the stage 120 is movable in the horizontal direction, and adjusts the relative positional relationship between the mounted substrate 30 and the mounting head 124. The stage 120 is made of a material capable of transmitting the electromagnetic wave 134 emitted from the irradiation unit 108, as described later in detail. The stage 120 has a multi-layer structure including a first layer having a thermal resistance in the plane direction higher than that in the thickness direction and a second layer arranged below the first layer. This will also be described later.

  The mounting head 124 mounts the semiconductor chips 12 stacked on the substrate 30. The mounting head 124 can hold the semiconductor chip 12 at its lower end, and is capable of rotating around the vertical rotation axis Rb and moving up and down. The mounting head 124 press-bonds the semiconductor chip 12 onto the substrate 30 or another semiconductor chip 12. Specifically, the mounting head 124 is lowered so as to press the held semiconductor chip 12 against the substrate 30 or the like, so that the semiconductor chip 12 is temporarily or permanently pressed. A temperature variable heater (not shown) is built in the mounting head 124, and the mounting head 124 is at a first temperature T1 when performing temporary pressure bonding and higher than the first temperature T1 when performing main pressure bonding. It is heated to the second temperature T2. Further, the mounting head 124 applies the first load F1 to the semiconductor chip 12 when executing the temporary pressure bonding and the second load F2 when performing the main pressure bonding.

  A camera (not shown) is provided near the mounting head 124. The substrate 30 and the semiconductor chip 12 are each provided with an alignment mark serving as a positioning reference. The camera captures an image of the substrate 30 and the semiconductor chip 12 so that the alignment mark can be seen. The control unit 130 grasps the relative positional relationship between the substrate 30 and the semiconductor chip 12 based on the image data obtained by this imaging, and if necessary, the rotation angle of the mounting head 124 about the axis Rb and the horizontal direction of the stage 120. Adjust the position.

  The irradiation unit 108 locally heats the substrate 30 by irradiating the electromagnetic wave 134 having a specific wavelength from the back side of the stage 120. The irradiation unit 108 has at least an electromagnetic wave source 132 that irradiates an electromagnetic wave 134. The electromagnetic wave 134 is not particularly limited as long as it has a wavelength that easily passes through the stage 120 and is easily absorbed by the substrate 30, but considering the output and directivity, the electromagnetic wave 134 is preferably laser light. The electromagnetic wave source 132 is not particularly limited as long as it can emit light having a desired wavelength and power with a desired power, and for example, a laser oscillator, an LD (Laser Diode), an LED, a Halongen lamp, or the like can be used. it can. The irradiation unit 108 further includes optical members such as a diaphragm, a lens, a mirror, and an optical fiber in order to irradiate only a specific area of the substrate 30 with the electromagnetic waves, and a driving member that drives these optical members to scan the electromagnetic waves. And so on.

  The control unit 130 controls the drive of each unit, and includes, for example, a CPU that performs various calculations and a storage unit that stores various data and programs. The control unit 130 drives each unit according to the program stored in the storage unit to execute the semiconductor chip mounting process. For example, the control unit 130 drives the mounting head 124 and the stage 120 to mount the semiconductor chip on the substrate 30. Further, the control unit 130 drives the irradiation unit 108 to locally heat the substrate 30 in parallel with the main pressure bonding process described later.

  Next, the semiconductor device 10 manufactured by the mounting apparatus 100 will be described with reference to FIGS. 3 is a schematic diagram showing an example of the semiconductor device 10, FIG. 4 is a schematic diagram of the substrate 30, and FIG. 5 is a schematic diagram of the semiconductor chip 12. Note that, in FIG. 3, thick lines at the boundary between the semiconductor chip 12 and the substrate 30 and at the boundary between the two semiconductor chips 12 indicate that the main compression bonding is performed.

  As shown in FIG. 3, the semiconductor device 10 handled in this example has a plurality of (four in the illustrated example) semiconductor chips 12 stacked and mounted on the upper surface of a substrate 30. In this example, a silicon wafer is used as the substrate 30. Therefore, the mounting process disclosed in this specification is a “chip-on-wafer process” in which the semiconductor chips 12 are stacked and mounted on the circuit formation surface of the silicon wafer.

  The substrate 30, which is a silicon wafer, is mainly made of silicon and has a higher thermal conductivity than a general circuit board made of resin or glass. As shown in FIG. 2, a plurality of mounting sections 34 arranged in a grid pattern are set on the substrate 30. A plurality of semiconductor chips 12 are stacked and mounted in each mounting section 34. The mounting sections 34 are arranged at a predetermined arrangement pitch P. The value of the arrangement pitch P is appropriately set according to the size of the semiconductor chip 12 to be mounted and the like. Further, in the present embodiment, the mounting section 34 has a substantially square shape, but may have another shape, for example, a substantially rectangular shape, as appropriate. Electrodes 36 (see FIG. 3) are formed on the surface of each mounting section 34 at positions corresponding to the bumps 18 of the semiconductor chip 12 to be mounted.

  Next, regarding the configuration of the semiconductor chip 12, as shown in FIG. 4, electrode terminals 14 and 16 are formed on the upper and lower surfaces of the semiconductor chip 12. Further, bumps 18 are formed on one surface of the semiconductor chip 12 so as to be continuous with the electrode terminals 14. The bump 18 is made of a conductive metal and melts at a predetermined melting temperature Tm.

  Further, a non-conductive film (hereinafter referred to as “NCF”) 20 is attached to one surface of the semiconductor chip 12 so as to cover the bumps 18. The NCF 20 functions as an adhesive that bonds the semiconductor chip 12 to the substrate 30 or another semiconductor chip 12, and is a non-conductive thermosetting resin such as polyimide resin, epoxy resin, acrylic resin, or phenoxy resin. , Polyethersulfone resin, etc. The thickness of the NCF 20 is larger than the average height of the bump 18, and the bump 18 is almost completely covered by the NCF 20. Although the NCF 20 is a solid film at room temperature, it gradually reversibly softens and exhibits fluidity when it exceeds a predetermined softening start temperature Ts, and becomes irreversible when it exceeds a predetermined hardening start temperature Tt. Begins to harden.

  Here, the softening start temperature Ts is lower than the hardening start temperature Tt and the melting temperature Tm of the bump 18. The first temperature T1 for temporary pressure bonding is higher than the softening start temperature Ts and lower than the melting temperature Tm and the hardening start temperature Tt. Further, the second temperature T2 for the main pressure bonding is higher than the melting temperature Tm and the curing start temperature Tt. That is, Ts <T1 <(Tm, Tt) <T2.

  When the semiconductor chip 12 is temporarily pressure-bonded to the substrate 30 or the lower semiconductor chip 12 (hereinafter, referred to as “mounting body” when the two are not distinguished from each other), the mounting head 124 is heated to the first temperature T1. Then, the semiconductor chip 12 is pressed. At this time, the NCF 20 of the semiconductor chip 12 is heated to near the first temperature T1 by heat transfer from the mounting head 124, softens, and has fluidity. As a result, the NCF 20 flows into the gap between the semiconductor chip 12 and the mounted body, and the gap can be reliably filled.

  When the semiconductor chip 12 is permanently pressure-bonded to the mounted body, the mounting head 124 is heated to the second temperature T2 and then the semiconductor chip 12 is pressed. At this time, the bump 18 and the NCF 20 of the semiconductor chip 12 are heated to near the second temperature T2 by the heat transfer from the mounting head 124. As a result, the bumps 18 are melted and can be welded to the opposing mounted body. Further, due to this heating, the NCF 20 is cured in a state where the gap between the semiconductor chip 12 and the mounted body is filled, so that the semiconductor chip 12 and the mounted body are firmly fixed. That is, the semiconductor chip 12 is thermocompression bonded to the substrate 30 or the like during the main compression bonding.

  Here, it takes a certain time to switch the temperature of the mounting head 124 from the first temperature T1 to the second temperature T2 or from the second temperature T2 to the first temperature T1. Therefore, in order to reduce the manufacturing time of the semiconductor device 10, it is effective to reduce the number of times the temperature of the mounting head 124 is switched. Therefore, when stacking and mounting a plurality of semiconductor chips 12, a process has been proposed in which all the semiconductor chips 12 are temporarily pressure-bonded, and then the temporarily pressure-bonded semiconductor chips 12 are finally pressure-bonded. Specifically, first, using the mounting head 124 heated to the first temperature T1, the temporary stacked body STt formed by stacking the plurality of semiconductor chips 12 while temporarily pressure-bonding is formed in the plurality of mounting sections 34. Subsequently, the mounting head 124 that has been switched to the second temperature T2 pressurizes the upper surface of the temporary stacked body STt, so that the plurality of semiconductor chips 12 that form the temporary stacked body STt are collectively press-bonded together. By mounting the semiconductor chip 12 in this procedure, the number of times the temperature of the mounting head 124 is switched can be significantly reduced, and the manufacturing time of the semiconductor device 10 can be significantly reduced.

  By the way, as is apparent from the above description, in order to properly mount the semiconductor chip 12, it is desired that the semiconductor chip 12 to be mounted is heated to an appropriate temperature according to the processing process. For example, when the main pressure bonding is performed, the semiconductor chip 12 must be heated to the curing start temperature Tt of the NCF 20 or higher and the melting temperature Tm of the bump 18 or higher. However, it may be difficult to heat all the semiconductor chips 12 to an appropriate temperature only with the heat from the mounting head 124. In particular, when the plurality of semiconductor chips 12 forming the stacked body STt are collectively press-bonded together, it is difficult to appropriately heat the lowermost semiconductor chip 12 only by the heat from the mounting head 124.

  Further, in one temporary stacked body STt, it is desired that the temperature difference between the uppermost semiconductor chip 12 and the lowermost semiconductor chip 12 (hereinafter referred to as “temperature difference in stacked body”) ΔT is small. If the temperature difference ΔT in the laminated body is large, the mounting quality varies. However, it was difficult to reduce the temperature difference ΔT in the laminated body only by the heat from the mounting head 124.

  Therefore, conventionally, a heater is often built in the stage 120 on which the substrate 30 is placed and the entire substrate 30 is also heated. According to this configuration, since the temporary stacked body STt is also heated from the lower side, the semiconductor chip 12 in the lowermost layer is easily heated to an appropriate temperature, and the temperature difference ΔT in the stacked body can be reduced to some extent.

  However, when heating the entire stage 120, the temperature must be sufficiently lower than the curing start temperature Tt of the NCF 20 as a matter of course. This is because when the temperature of the stage 120 is higher than the curing start temperature Tt, the NCF 20 of the semiconductor chip 12 after the temporary pressure bonding and before the main pressure bonding is thermally cured. Therefore, the stage 120 cannot be heated to a very high temperature, and it is difficult to sufficiently reduce the temperature difference ΔT in the stacked body.

  Even if the stage 120 has a temperature lower than the curing start temperature Tt, if the entire stage 120 is heated, the semiconductor chip 12 temporarily or permanently pressure-bonded onto the substrate 30 is exposed to heat for a long time. It will continue to be entered. Such heat input over a long period of time causes deterioration of the semiconductor chip 12, particularly the NCF 20, and eventually deterioration of mounting quality.

  Therefore, as described above, in the mounting apparatus 100 disclosed in this specification, the irradiation unit 108 is arranged below the stage 120, and the substrate 30 is locally heated by the electromagnetic wave 134. FIG. 5 is an image diagram showing how the substrate 30 is locally heated. Although FIG. 5 shows three mounting sections 34, in the following description, these mounting sections 34 will be referred to as “section A”, “section B”, and “section C” in order from the left side of the drawing. Call and distinguish. Further, in FIG. 5, the thick line at the boundary between the semiconductor chip 12 and the mounted body (the substrate 30 or the other semiconductor chip 12) indicates the main pressure bonding, and the broken line indicates the temporary pressure bonding. ing. Therefore, in FIG. 5, the stacked body of the section A is the chip stacked body STc that is subjected to the main pressure bonding, and the stacked body of the sections B and C is the temporary stacked body STt after the temporary pressure bonding and before the main pressure bonding. FIG. 5 shows a state where the temporary laminate STt in the section B is subjected to main pressure bonding.

  As shown in FIG. 5, when one temporary laminated body STt is permanently pressure-bonded, the temporary laminated body STt is heated and pressed by the mounting head 124 heated to the second temperature T2. In addition, in the substrate 30, the section B in which the temporary stacked body STt to be permanently bonded is arranged is irradiated with the electromagnetic wave 134, and the section B is heated by the electromagnetic wave 134.

  Here, as described above, the electromagnetic wave 134 has a wavelength that easily passes through the stage 120 and is easily absorbed by the substrate 30. In this example, the substrate 30 is a silicon wafer. The transmittance of silicon sharply drops below a wavelength of 1200 nm. Therefore, when a silicon wafer is used as the substrate 30, the wavelength of the electromagnetic wave 134 is preferably 1200 nm or less. However, if the wavelength is too small, the energy of the electromagnetic wave also decreases, so the wavelength of the electromagnetic wave 134 is preferably larger than that of visible light, that is, 750 nm or more.

  Further, it is desirable that the stage 120 has a high transmittance of the electromagnetic wave 134. It is also desired that the stage 120 be made of a material having poor heat conductivity. This is to prevent the heat of the mounting section 34 heated by the electromagnetic wave 134 from being transferred to the other mounting section 34 via the stage 120. In order to satisfy these conditions, it is desirable that the stage 120 be made of, for example, quartz, barium fluoride, magnesium fluoride, calcium fluoride, or the like.

  The irradiation range of the electromagnetic wave 134 is preferably substantially the same as the outer shape of the semiconductor chip 12. Further, the irradiation unit 108 preferably has a changing unit that changes at least one of the irradiation range and the irradiation position of the electromagnetic wave 134 in order to irradiate the electromagnetic wave 134 only in a desired range. There are various conceivable configurations of the changing unit, but the changing unit may include, for example, a moving mechanism that moves the position of the electromagnetic wave source 132 with respect to the stage 120. Examples of such a moving mechanism include an XY moving mechanism that moves the stage 120. Further, in order to irradiate only a desired irradiation range, the changing means is provided, for example, as shown in FIG. 5, in the middle of the path of the electromagnetic wave 134 having a diameter sufficiently larger than the irradiation range, and an opening corresponding to the irradiation range. You may have the diaphragm 135 with which was formed. The diaphragm 135 may be appropriately replaced depending on the target semiconductor device.

  As another form, the irradiation range may be scanned with an electromagnetic wave 134 having a diameter sufficiently smaller than the irradiation range in the vicinity of the substrate 30. In order to obtain the small-diameter electromagnetic wave 134 near the substrate 30, an electromagnetic wave source 132 that emits a small-diameter parallel electromagnetic wave (for example, parallel light) may be used, or an optical member (lens or the like) may be used to generate the large-diameter electromagnetic wave 134. Focusing may be performed around the substrate 30. In order to scan the electromagnetic wave 134, the electromagnetic wave source 132 itself may be moved, or a mirror or the like that bends the electromagnetic wave 134 may be moved. As a mode of moving the mirrors, for example, a galvano mirror mechanism in which two or more mirrors are driven by a galvano motor may be used. A coil motor or a cam may be used as a mechanism for driving the mirror or the electromagnetic wave source 132.

  As another form, in order to irradiate only a desired irradiation range, various optical members may be used to change the profile (size, shape, etc.) of the electromagnetic wave 134. For example, a rectangular core fiber having a geometrical beam forming function may be used. As another form, a kaleidoscope having a plurality of mirrors attached to the inner surface of the cylindrical body may be arranged in the path of the electromagnetic wave 134. Furthermore, the profile of the electromagnetic wave 134 may be changed by using a diffractive lens, a flyer lens, or another optical lens instead of or in addition to the above-mentioned optical member.

  Further, although only one electromagnetic wave source 132 is illustrated in FIG. 1, two or more electromagnetic wave sources 132 may be provided, and the two or more electromagnetic wave sources 132 may be the same kind of electromagnetic wave source. Different types of electromagnetic wave sources may be used. Further, it is desirable that the power of the electromagnetic wave 134 can heat the substrate 30 to a desired temperature for a desired time. For example, when the temporary stacked bodies STt are collectively pressure-bonded together, it is desired to heat the lowermost semiconductor chip 12 to the same temperature as the uppermost semiconductor chip 12. Usually, since the execution time of the main pressure bonding is several seconds, it is desirable that the electromagnetic wave 134 has a power enough to heat the substrate 30 to the second temperature T2 during the main pressure bonding (within several seconds).

  In any case, the electromagnetic wave 134 is absorbed in the substrate 30 by irradiating the electromagnetic wave 134 having a wavelength that is easily transmitted through the stage 120 and easily absorbed by the substrate 30. Then, the energy of the absorbed electromagnetic waves is converted into heat, so that only the area of the substrate 30 irradiated with the electromagnetic waves 134 is locally heated. Then, by locally heating the substrate, the semiconductor chip 12 located on the heated portion (irradiated portion) is also heated. By performing such local heating (irradiation of the electromagnetic wave 134) only in the mounting section 34 in which the main pressure bonding process is performed, the semiconductor chip 12 in the lowermost layer can be appropriately heated, and good mounting quality can be obtained. Further, by locally heating the mounting section 34 in which the main pressure bonding process is performed, the temperature difference ΔT in the stacked body can be reduced, and the mounting quality of the plurality of semiconductor chips 12 forming one stacked body can be made uniform.

  On the other hand, the mounting section 34 that is not subjected to the main pressure bonding process is not irradiated with the electromagnetic wave 134, so that the mounting region 34 is not deteriorated or deteriorated due to the temperature rise of the mounting region and eventually the heat of the semiconductor chip 12 that is not the target of the main pressure bonding process. It can be effectively prevented.

  However, when only the mounting section 34 that is the object of main pressure bonding is heated by the electromagnetic wave 134, part of the heat generated in the mounting section 34 is transferred to the other mounting section 34 via the substrate 30 and the stage 120. It For example, in FIG. 5, even when only the section B is heated by the electromagnetic wave 134, part of the heat generated in the section B flows to the sections A and C via the substrate 30 and the stage 120. To do. Such heat outflow may lead to deterioration of thermal efficiency and thermal deterioration of the semiconductor chips 12 in the sections A and B not subjected to the main pressure bonding process.

  Therefore, in the mounting apparatus 100 disclosed in the present specification, in order to reduce the heat transfer to the mounting section other than the mounting section to be heated, the stage 120 is made of a material having poor heat conductivity, such as quartz, as described above. I am configuring. Further, in this example, in order to reduce heat transfer in the surface direction through the stage 120, a plurality of grooves are formed on the surface of the stage 120. By forming such grooves, a plurality of air layers (groove portions) are present in the middle of the route toward the surface direction, and the thermal resistance in the surface direction increases. In the following, of the stage 120, the portion where the groove is formed is referred to as a “first layer 122”, and the solid portion disposed below the first layer 122 is referred to as a “second layer 123”. Since the first layer 122 has a plurality of grooves formed on its surface, the thermal resistance in the surface direction is higher than the thermal resistance in the thickness direction. Further, since the second layer 123 has a solid structure, the second layer 123 has a lower thermal resistance in the surface direction than the first layer 122, but has a high strength and is hard to bend.

  The pitch of the grooves formed in the first layer 122 is not particularly limited, but is, for example, sufficiently smaller than one side of the semiconductor chip 12 (for example, the groove pitch is 1/10 or less of one side of the semiconductor chip). Good. Since the groove pitch is small and the number of grooves is large, stress concentration occurring at the contact portion between the edge of the groove and the substrate 30 can be relaxed, and when bonding (temporary pressure bonding, main pressure bonding) is performed. In addition, the pressure applied to the entire semiconductor chip 12 can be made uniform. Further, as another form, the pitch of the grooves may be the same as the arrangement pitch P of the mounting sections 34, and the grooves may be arranged at substantially the same position as the boundary line of the mounting sections 34. In other words, the groove may not exist directly below the semiconductor chip 12, and the groove may exist only between two semiconductor chips 12 that are adjacent to each other in the surface direction. With this configuration, the pressure applied to the entire semiconductor chip 12 can be made more uniform during the bonding (temporary pressure bonding, main pressure bonding). Further, the groove formed in the first layer 122 may be communicated with a suction mechanism (not shown) for suction-holding the placed substrate 30.

  Thus, by providing the first layer 122 having a thermal resistance in the surface direction higher than the thermal resistance in the thickness direction on the surface layer of the stage 120, heat transfer in the surface direction via the stage 120 can be effectively prevented. . This will be described with reference to FIG. FIG. 6 is an enlarged view of the X part of FIG. It is assumed that only the section B is heated by the electromagnetic wave 134 by the irradiation unit 108. In this case, the heat generated in the section B is transferred upward (semiconductor chip 12 side), in the surface direction (sections A and C side), and downward (stage 120 side). Here, in order to improve the thermal efficiency, of the heat generated in the section B, the amount of heat transferred to the upper side (semiconductor chip 12 side) is increased so that the surface direction (sections A and C side) and the lower side (stage 120 side). It is desirable to reduce the amount of heat transferred to. When the substrate 30 is a silicon wafer having a high heat transfer property, it is difficult to reduce the amount of heat transfer in the surface direction (parts A and C sides). On the other hand, in this example, the stage 120 is made of a material having a high heat insulating property, and a plurality of grooves are formed on the surface of the stage 120 to reduce the contact area with the substrate 30. The amount of heat transfer to the can be effectively reduced. That is, the stage 120 is made of a material having a high heat insulating property, and the contact area between the stage 120 and the substrate 30 is reduced, so that the thermal efficiency at the time of heating the semiconductor chip 12 by the irradiation unit 108 can be improved.

  However, although the amount of heat transferred to the stage 120 is small, it cannot be zero. When the heat transferred to the stage 120 is transferred in the surface direction (sides of the sections A and C) via the stage 120, the amount of heat input to the semiconductor chips 12 other than the heating target increases. However, since the stage 120 of the present example has the first layer 122 having a high thermal resistance in the surface direction, heat may be transferred in the surface direction (sections A and C sides) via the stage 120. Effectively prevented. As a result, the amount of heat input to the semiconductor chip 12 other than the heating target can be reduced, and the deterioration or deterioration of the semiconductor chip 12 due to the heat can be prevented.

  By the way, when the semiconductor chip 12 is bonded (temporary pressure bonding, main pressure bonding), pressure is applied to the semiconductor chip 12 using the mounting head 124. When the stage 120 includes only the first layer 122 having high thermal resistance in the surface direction, the stage 120 may not be able to withstand the load applied during bonding, and the flatness of the substrate 30 may not be maintained. Therefore, in this example, the second layer 123 having higher rigidity than the first layer 122 is provided below the first layer 122. As a result, even when a large load is applied, it is difficult to bend and the flatness of the substrate 30 can be maintained.

  Next, a flow of manufacturing the semiconductor device 10 using the mounting apparatus 100 will be described. In the case of manufacturing the semiconductor device 10, first, a mounting step of directly mounting the substrate 30 on the stage 120 is executed. Subsequently, a bonding step of bonding the semiconductor chip 12 to the upper surface of the substrate 30 using the mounting head 124 is performed. This bonding process is further roughly classified into a temporary pressure bonding process and a main pressure bonding process.

  In the temporary pressure bonding step, the mounting head 124 stacks the plurality of semiconductor chips 12 in all the mounting sections 34 while performing temporary pressure bonding to form a temporary stacked body STt. Specifically, the mounting head 124 is heated to the first temperature T1 in advance. In that state, first, the stage 120 is horizontally moved to arrange one mounting section 34 directly below the mounting head 124. The mounting head 124 sucks and holds the tip of the semiconductor chip 12 transported by the chip transport unit 104, and then descends, so that the semiconductor chip 12 is mounted on the mounted body (the substrate 30 or another semiconductor chip 12). It is placed on top and pressed by the first load F1. As a result, the NCF 20 of the semiconductor chip 12 is softened and the semiconductor chip 12 is temporarily pressure-bonded. This temporary pressure bonding work is repeated a plurality of times to form the temporary stacked body STt in one mounting section 34. If the temporary stacked body STt can be formed in one mounting section 34, the stage 120 moves in the horizontal direction so that the other mounting section 34 is located directly below the mounting head 124. Then, again, the mounting head 124 is used to form the temporary stacked body STt. After that, the same processing is performed on all the mounting sections 34.

  If the temporary stacked body STt can be formed in all the mounting sections 34, subsequently, the main pressure bonding step is executed. In the main pressure bonding step, the main pressure bonding process is sequentially performed on the plurality of stacked bodies STt. Specifically, the mounting head 124 switches the temperature from the first temperature T1 to the second temperature T2. Further, in this state, the stage 120 is horizontally moved to arrange one mounting section 34 directly below the mounting head 124. In this state, the mounting head 124 descends and presses the upper surface of one temporary stacked body STt with the second load F2. As a result, the plurality of semiconductor chips 12 forming the one temporary laminated body STt are collectively and permanently pressure-bonded.

  Here, in parallel with the main pressure bonding process, a substrate heating step of locally heating the mounting section 34 in which the one temporary stacked body STt is arranged is also performed. Specifically, the target mounting section 34 (the area directly below the mounting head 124) is irradiated with the electromagnetic wave 134 to locally heat only the mounting section 34. As a result, the temperature of the target mounting section 34 rises, and the semiconductor chip 12 arranged on the mounting section is also heated. Thus, the main pressure bonding process can be performed in a state where the temperature difference between the upper layer and the lower layer of the temporary laminate STt (temperature difference ΔT in the laminate) is small. As a result, the mounting quality of the semiconductor chip 12 can be further improved.

  When one temporary stacked body STt is permanently pressure-bonded, the stage 120 moves in the horizontal direction so that the other mounting section 34 is located directly below the mounting head 124. Then, again, heating and pressurization of the temporary stacked body STt using the mounting head 124 and local heating of the substrate 30 by the electromagnetic wave 134 are performed. Then, if the same process is performed on all the mounting sections 34, the manufacturing process of the semiconductor device 10 is completed.

  As is clear from the above description, according to the method of manufacturing the semiconductor device 10 disclosed in the present specification, the electromagnetic wave 134 is emitted to the mounting section 34 of the substrate 30 on which the semiconductor chip 12 to be heated is mounted. As a result, only the mounting section 34 is heated by the electromagnetic wave 134. As a result, the semiconductor chip 12 to be heated can be appropriately heated, while heat can be prevented from being input to the semiconductor chip 12 not to be heated for a long time. Further, by providing the stage 120 with the first layer 122 having a heat resistance in the surface direction higher than that in the thickness direction and the second layer 123 having a high rigidity, the flatness of the substrate 30 is maintained. The heat transfer to the semiconductor chip 12 which is not the heating target via the stage 120 is reduced. As a result, the mounting quality of the semiconductor chip 12 can be further improved.

  The configurations described so far are all examples, and may be changed as appropriate. For example, although a silicon wafer is used as the substrate 30 in the above description, for example, a wafer made of silicon carbide (SiC), gallium nitride (GaN), sapphire, or the like may be used as the substrate 30. Further, instead of the wafer, a resin substrate, a glass substrate or the like may be used as the substrate 30.

  By the way, it is difficult to heat some of these substrates and wafers by the electromagnetic wave 134. In this case, the substrate 30 is not directly mounted on the stage 120, but the intermediate member 140 that absorbs the electromagnetic wave 134 may be disposed between the stage 120 and the substrate 30. The intermediate member 140 is not particularly limited as long as it is made of a material that easily absorbs the electromagnetic wave 134. Therefore, the intermediate member 140 may be a substantially flat plate-shaped member arranged on the upper surface of the stage 120, as shown in FIG. 7. As another form, if the intermediate member 140 is made of a material that absorbs the electromagnetic wave 134, as shown in FIG. 8, it may be a coating (for example, a black body coating) that covers the surface of the stage 120. .

  In any case, by providing the intermediate member 140 that absorbs the electromagnetic wave 134 between the stage 120 and the substrate 30, the substrate 30 can be always heated by the electromagnetic wave 134 regardless of the type of the substrate 30. . When the intermediate member 140 is provided, the stage 120 may have a structure that does not have the first layer 122. For example, the intermediate member 140 may be placed on the solid block-shaped stage 120, and the substrate 30 may be placed on the intermediate member 140.

  Further, in the description so far, the first layer 122 provided on the stage 120 has been described as a portion in which a plurality of grooves are formed, but the first layer 122 has a thermal resistance in the surface direction which is higher than that in the thickness direction. Other configurations may be used as long as they are expensive. For example, as shown in FIG. 9, the first layer 122 and the second layer 123 may be separate members. However, even in this case, it is desirable that both the first layer 122 and the second layer 123 easily transmit the electromagnetic wave 134. The thermal conductivity of the material forming the first layer 122 is preferably equal to or lower than the thermal conductivity of the material forming the second layer 123. Therefore, for example, when the wavelength of the electromagnetic wave 134 is 1200 nm or less and the second layer 123 is made of quartz, the first layer 122 may be made of an optical plastic material that transmits near infrared rays.

  Next, another embodiment of the present invention will be described. FIG. 11 is a schematic diagram showing a heating device and a diagram showing the intensity of electromagnetic waves. It should be noted that illustration of a substrate and stacked semiconductor chips is omitted in the drawings.

  As shown in FIG. 11A, an irradiation unit 150a according to another embodiment emits an electromagnetic wave that heats the semiconductor chip 100, and a lens 152 that adjusts the direction of the electromagnetic wave emitted by the electromagnetic wave source 151. With. The electromagnetic wave source 151 is, for example, a laser diode, but may be a semiconductor light source such as an LED, a laser source such as a gas laser, or a lamp heater such as a halogen lamp. Further, the lens 152 can be omitted depending on the type and characteristics of the electromagnetic wave source 151. The irradiation unit 150a of the present embodiment has a flat output characteristic in the irradiation range, as shown in FIG.

  The lens 152 refracts the electromagnetic wave emitted by the electromagnetic wave source 151 and irradiates the electromagnetic wave on a range corresponding to the semiconductor chip 101. The irradiation unit 150a is driven in the surface direction of the stage 120 by a driving device (not shown), and irradiates the semiconductor chip 101 to be heated with electromagnetic waves to heat the semiconductor chip 101. Note that the irradiation unit 150a may be fixed and the stage 120 may be driven.

  Further, as shown in FIG. 11B, a movable or fixed diaphragm 153 may be provided between the lens 152 and the stage 120 in the irradiation unit 150a to narrow the range where the electromagnetic waves are irradiated. As a result, it is possible to suppress the heating of the portion other than the semiconductor chip 12 that is the heating target. Note that the diaphragm 153 is, for example, a movable ring diaphragm, but may have a rectangular opening according to the shape of the semiconductor chip 12.

  Further, as shown in FIG. 11C, a prism 154 having an opening at the center may be provided in the irradiation unit 150a between the lens 152 and the stage 120. The prism 153 is formed of a transparent member such as glass or acrylic, and refracts the electromagnetic wave emitted from the lens 152 to concentrate and irradiate the peripheral portion of the semiconductor chip 12. By providing the prism 153, the output to the peripheral portion where the temperature of the semiconductor chip 12 is apt to decrease is increased, so that the in-plane temperature unevenness of the semiconductor chip 12 can be reduced. The prism 154 has, for example, a ring shape having an opening at the center, but may have a rectangular opening according to the shape of the semiconductor chip 12.

  Further, as shown in FIG. 11D, a plate member 155 having a light shielding portion 156 in the center is provided between the lens and the stage 120 to reduce the output of the electromagnetic wave with which the central portion of the semiconductor chip 12 is irradiated. Good. Alternatively, as shown in FIG. 11E, a plate member 155 having a diffusion portion 157 in the center may be provided to diffuse the electromagnetic waves in the central portion and irradiate the semiconductor chip 12. By reducing the output of the central portion and contributing to the heating of the peripheral portion of the chip by the scattered light, it is possible to reduce the temperature unevenness within the surface of the semiconductor chip 12. The plate member 155 has, for example, a disc shape, but may have a rectangular shape according to the shape of the semiconductor chip 12.

  Furthermore, another embodiment of the present invention is shown in FIGS. As shown in FIG. 12A, the irradiation unit 150b of the present embodiment includes an electromagnetic wave source 151 that irradiates the stage 120 with an electromagnetic wave having a Gaussian curve output characteristic through the lens 152.

  In this embodiment, as shown in FIG. 12B, a cone-shaped prism 158 is arranged between the lens 152 and the stage 120 to increase the intensity of electromagnetic waves emitted to the peripheral portion of the semiconductor chip 12. May be. Further, the position of the prism 158 may be adjusted to reduce the intensity of the electromagnetic wave with which the central portion of the semiconductor chip 12 is irradiated and to enhance the intensity of the peripheral portion. The prism 158 is, for example, a cone having a convex portion in the center, but may be a quadrangular pyramid according to the shape of the semiconductor chip 12.

  As another form, the first layer 122 may be processed into a predetermined shape in order to increase the thermal resistance in the surface direction of the first layer 122 higher than the thermal resistance in the thickness direction. The “processing” here is not limited to mechanical processing such as removing a part of the material with a milling machine, but also includes molding processing such as plastic injection molding. Therefore, for example, as described above, the first layer 122 improves the thermal resistance in the surface direction by forming a plurality of grooves or forming holes in the layer as shown in FIG. May be. In this case, the first layer 122 and the second layer 123 may be integrated or may be separate members.

  Further, in the above description, the substrate 30 is heated by the electromagnetic wave 134 only when the temporary stacked body STt is subjected to the main pressure bonding collectively, but if necessary, the substrate 30 is heated by the electromagnetic wave 134 during the temporary pressure bonding. Good. Further, in the above description, only the case where the plurality of semiconductor chips 12 are stacked and mounted is illustrated, but the technique disclosed in the present specification can be naturally applied to the case where the semiconductor chips 12 are not stacked and mounted.

  Further, in the above description, the mounting head 124 and the irradiation unit 108 are one, but if necessary, a plurality of these may be provided, and the plurality of them may be simultaneously pressure-bonded or heated by the electromagnetic wave 134 of the substrate 30. You may go.

10 semiconductor devices, 12 semiconductor chips, 14 electrode terminals, 16 electrode terminals, 18 bumps, 30 substrates, 34 mounting sections, 36 electrodes, 100 mounting devices, 102 chip supply units, 104 chip transport units, 106 bonding units, 108 irradiation units , 110 protrusion, 114 die picker, 116 transfer head, 118 turntable, 120 stage, 122 first layer, 123 second layer, 124 mounting head, 130 control unit, 132 electromagnetic wave source, 134 electromagnetic wave, 140 intermediate member, 150a, 150b irradiation unit, 151 electromagnetic wave source, 152 lens, 153 diaphragm, 154 prism, 155 plate member, 156 light shielding part, 157 diffusion part, 158 prism, STc chip laminated body, STt temporary laminated body.

Claims (12)

A mounting device for manufacturing a semiconductor device by bonding a semiconductor chip to a mounted object which is a substrate or another semiconductor chip,
A stage having a first surface on which the substrate is mounted directly or via an intermediate member, and a second surface opposite to the first surface,
A mounting head that is movable relative to the stage and that bonds the semiconductor chip to the mounted body,
An irradiation unit having an electromagnetic wave source that outputs an electromagnetic wave that heats the substrate or the intermediate member while passing through the stage, and an adjustment mechanism that adjusts the intensity distribution of the electromagnetic wave with respect to the semiconductor chip.
Equipped with
The stage has a first layer formed on the first surface side,
The first layer, the thermal resistance in the plane direction is greater than the thermal resistance in the thickness direction,
A mounting device characterized by the above. The mounting apparatus according to claim 1, wherein
The adjustment mechanism is a diaphragm mechanism that narrows the irradiation range of the electromagnetic waves,
A mounting device characterized by the above. The mounting apparatus according to claim 1, wherein
The adjusting mechanism irradiates the semiconductor chip with a higher intensity of the electromagnetic waves applied to the peripheral portion of the semiconductor chip than the intensity of the central portion of the semiconductor chip,
A mounting device characterized by the above. The mounting apparatus according to claim 3,
The adjusting mechanism is a prism having an opening in the center,
A mounting device characterized by the above. The mounting apparatus according to claim 3,
The adjusting mechanism is a cone-shaped prism having a convex portion in the center,
A mounting device characterized by the above. The mounting apparatus according to claim 1, wherein
The adjusting mechanism is a plate member having a light shielding portion in the center,
A mounting device characterized by the above. The mounting apparatus according to claim 1, wherein
The adjustment mechanism is a plate member having a diffusion portion in the center,
A mounting device characterized by the above. The mounting apparatus according to any one of claims 1 to 7, wherein:
The stage further has a second layer formed on the second surface side of the first layer,
The first layer has a larger thermal resistance in the surface direction than the second layer,
A mounting device characterized by the above. The mounting apparatus according to claim 7, wherein
The mounting device, wherein the second layer has higher rigidity than the first layer. The mounting apparatus according to claim 8 or 9, wherein
The second layer is a solid portion made of a material that can transmit the electromagnetic waves,
The first layer is a portion having a plurality of grooves on the upper surface or a plurality of pores in the layer,
A mounting device characterized by the above. The mounting device according to any one of claims 1 to 10, wherein:
The substrate is a silicon wafer and is placed directly on the stage,
The electromagnetic wave has a wavelength of 1200 nm or less,
The substrate is locally heated by the electromagnetic waves,
A mounting device characterized by the above. The mounting apparatus according to any one of claims 1 to 11,
The substrate is placed on the stage via the intermediate member,
The electromagnetic wave has a wavelength that is absorbed by the intermediate member and not absorbed by the substrate,
The substrate is locally heated by heat transfer from the intermediate member that is locally heated by the electromagnetic wave,
A mounting device characterized by the above.

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