JP5532591B2 - Alignment apparatus, substrate bonding apparatus, and manufacturing method of stacked semiconductor device - Google Patents

Description

  The present invention relates to an alignment apparatus, a substrate bonding apparatus, and a method for manufacturing a stacked semiconductor device.

  There is a stacked semiconductor device in which substrates each having an element and a circuit formed thereon are stacked (see Patent Document 1). When the substrates are bonded together in the manufacture of the stacked semiconductor device, the pair of substrates are aligned and stacked with high accuracy, and then pressed and pressed. High alignment accuracy is required for an alignment apparatus (see Patent Document 2) used for alignment.

  The alignment apparatus is used in a temperature-controlled environment for the purpose of maintaining alignment accuracy. Thereby, not only the deformation of each member due to thermal expansion, but also a decrease in alignment accuracy due to air fluctuations is suppressed.

JP 11-261000 A JP 2005-251972 A

  In the alignment apparatus, the substrate is aligned while monitoring using a microscope. For this reason, illumination light for illuminating the observation target of the microscope is also introduced. However, when the light source is disposed in the vicinity of the substrate, the influence of heat radiated from the light source reduces the alignment accuracy. In addition, when only the illumination light is introduced into the alignment apparatus from the outside, the components of the alignment apparatus are required to avoid the optical path of the illumination light, so that the structure of the alignment apparatus is restricted.

  Therefore, in order to solve the above problem, as a first aspect of the present invention, an alignment apparatus for aligning a pair of substrates to be overlaid, a substrate holding unit that holds one of the pair of substrates, and a pair of substrates A movable stage that holds and displaces the other, a drive unit that moves the movable stage, a microscope that is moved by the drive unit together with the movable stage, and a microscope that images one substrate and is moved by the drive unit together with the microscope. An alignment device is provided that includes an illumination unit that generates illumination light that illuminates the observation target region.

  Moreover, as a second aspect of the present invention, there is provided a substrate bonding apparatus that includes the alignment apparatus and bonds a pair of substrates aligned by the alignment apparatus.

  The summary of the invention does not list all the features of the invention. Further, a sub-combination of these feature groups can be an invention.

  Hereinafter, the present invention will be described through embodiments of the invention. The embodiments described below do not limit the invention according to the claims. In addition, not all combinations of features described in the embodiments are essential for the solution of the invention.

  FIG. 1 is a plan view schematically showing the overall structure of the multilayer substrate manufacturing system 100. The multilayer substrate manufacturing system 100 includes a normal temperature part 102 and a high temperature part 202 formed in a common housing 101.

  The substrate 180 to be bonded is accommodated in the substrate cassette 110 and loaded into the housing 101. The bonded substrates 180 are collected in the substrate cassette 120 and carried out.

  The room temperature unit 102 includes an alignment unit 300 surrounded by a heat insulating wall 130 including a shutter 150. The alignment unit 300 aligns the pair of substrates 180 with high accuracy corresponding to the line width of the circuit formed on the substrate 180. The inside of the normal temperature unit 102 is temperature-controlled at a constant temperature close to room temperature, and the alignment accuracy in the alignment unit 300 is maintained.

  The high temperature unit 202 includes a pressurizing unit 240 surrounded by a heat insulating wall 230 including the shutter 250. The pressurizing unit 240 heats and pressurizes the pair of substrates 180 that are aligned and stacked and permanently bonds them. The shutter 250 and the heat insulating wall 230 surround the high temperature part 202 and prevent the high temperature of the pressurizing part 240 from affecting the accuracy of the alignment part 300.

  The pair of robot arms 160 conveys the substrate 180 between the substrate cassettes 110 and 120, the alignment unit 300, and the pressure unit 240. The robot arm 160 also has a function of turning over one of the pair of substrates 180 inserted in the alignment unit 300, as will be described later.

  The substrate 180 loaded in the multilayer substrate manufacturing system 100 may be a single silicon wafer, compound semiconductor wafer, glass substrate, or the like, in which elements, circuits, terminals, and the like are formed. In some cases, the substrate 180 to be loaded is a laminated substrate formed by already laminating a plurality of wafers.

  Furthermore, since the substrate 180 is fragile by itself, in the multilayer substrate manufacturing system 100, when the substrate 180 is held by the substrate holder 190 (see FIGS. 2a to 2e) having higher strength, both are handled together. There is. The substrate 180 is held by the substrate holder 190 by, for example, electrostatic adsorption.

  2a, 2b, 2c, 2d, and 2e are diagrams schematically showing changes in the state of the substrate 180 in the multilayer substrate manufacturing system 100. FIG. As shown in FIG. 2a, each of the substrates 180 is individually accommodated in, for example, the substrate cassette 110 when the multilayer substrate manufacturing system 100 starts operation.

  When the multilayer substrate manufacturing system 100 starts operation, the substrate 180 is carried into the alignment unit 300 one by one by the robot arm 160. When the substrate holder 190 is used, the substrate 180 is held by the substrate holder 190 before being carried into the alignment unit 300 as shown in FIG.

  Next, as shown in FIG. 2c, the alignment unit 300 holds the substrate 180 in a facing state. Further, the substrate 180 aligned in the alignment unit 300 is connected and positioned by a plurality of fasteners 192 fitted in the grooves 191 formed on the side surface of the substrate holder 190, as shown in FIG. 2d. Hold. The coupled substrate 180 and substrate holder 190 are transported integrally by the robot arm 160 and transported to the pressure unit 240.

  By being heated and pressurized in the pressure unit 240, the substrates 180 are permanently bonded to each other to form a laminated substrate. Thereafter, the substrate 180 and the substrate holder 190 are unloaded from the pressure unit 240 and collected in the substrate cassette 120.

  The substrate holder 190 is repeatedly used inside the multilayer substrate manufacturing system 100. Therefore, the multilayer substrate manufacturing system 100 is not taken out of the casing 101 while it is operating.

  FIG. 3 is a plan view schematically showing the form of the substrate 180 that is a material of the laminated substrate. As illustrated, a plurality of element regions 186 are formed on the substrate 180, and alignment marks 184 are disposed in the vicinity of each of the element regions 186. Further, the substrate 180 has a notch 182 formed at a specific portion of the edge. The notches 182 are arranged corresponding to the crystal orientation of the substrate 180 and the like, and show the physical properties and the anisotropy of the arrangement in the substrate 180 having a substantially circular shape as a whole.

  The alignment mark 184 is used as an index when the element region 186 is formed on the substrate 180. For this reason, the position of the alignment mark 184 is closely related to the position of the element region 186 displaced by the deformation of the substrate 180 or the like. Therefore, when the substrates 180 are stacked, the alignment mark 184 is used as an alignment index, so that distortion generated in each substrate 180 can be effectively compensated.

  In the drawing, the element regions 186 and the alignment marks 184 are drawn large, but the number of element regions 186 formed on a large substrate 180 such as 300 mmφ is several hundred or more. Accordingly, the number of alignment marks 184 arranged on the substrate 180 also increases. Further, the alignment mark 184 can be substituted with wiring, bumps, scribe lines, etc. formed on the substrate 180.

  FIG. 4 is a cross-sectional view schematically showing the structure of the alignment unit 300. The alignment unit 300 includes an upper stage unit 320, a lower stage unit 360, a driving unit 350, and a pair of microscope units 380 and 390 arranged inside the frame 310.

  The frame 310 includes a top plate 312 and a bottom plate 316 that are parallel to each other and a plurality of support columns 314 that couple the top plate 312 and the bottom plate 316. The top plate 312, the support column 314, and the bottom plate 316 are each formed of a highly rigid material and do not deform even when a reaction force relating to the operation of the internal mechanism is applied.

  The upper stage unit 320 is fixed to the lower surface of the top plate 312 and holds the substrate holder 190 holding the substrate 180 on the lower surface. The lower stage unit 360 is disposed on the bottom plate 316 via the driving unit 350 and mounts the substrate holder 190 on which the substrate 180 is mounted. The lower stage unit 360 is mounted with reflecting mirrors 372 and 374 arranged orthogonal to each other together with the substrate holder 190. The reflecting mirrors 372 and 374 are used when the interferometer arranged in the alignment unit 300 measures the position of the lower stage unit 360.

  The drive unit 350 includes an X drive unit 354 that moves in the X direction while being guided by a guide rail 352 fixed to the bottom plate 316, a Y drive unit 356 that moves in the Y direction on the X drive unit 354, and a Y drive unit. And a cylinder 358 and a piston 359 that are mounted on 356 and move the lower stage 360 up and down in the Z direction.

  Thereby, the load on the lower stage unit 360 can be moved to an arbitrary position on the XY plane and can be moved up and down. Although not shown, the drive unit 350 further includes a θ drive unit that tilts or leveles the lower stage unit 360. Thereby, the inclination of the mounted substrate 180 can also be compensated. In this figure, the position of the alignment mark 184 formed on the substrate 180 is represented by a triangular symbol M.

  The microscope unit 380 includes a light source unit 382, a light guide 384, and a microscope 344, and is mounted on the Y drive unit 356 of the drive unit 350 together with the lower stage unit 360. Thereby, the relative position of the microscope unit 380 and the lower stage unit 360 moves together with the lower stage unit 360 in the X direction and the Y direction while maintaining a certain relative position. The distance between the center of the lower stage 360 and the center of the microscope 344 is previously measured and known.

  In the microscope unit 380, the light guide 384 guides the illumination light generated by the light source unit 382 toward the microscope 344. The microscope 344 is arranged to look up and observe the lower surface of the upper stage unit 320, and illuminates the observation target by emitting illumination light from the objective lens.

  The microscope unit 390 includes a light source unit 392, light guides 394 and 398, a relay unit 396, and a microscope 342, and is supported by the top plate 312 in common with the upper stage unit 320. The relative positions of the microscope unit 390 and the upper stage unit 320 are also known in advance by measurement.

  In the microscope unit 390, the light guides 394 and 398 and the relay unit 396 guide the illumination light generated by the light source unit 392 toward the microscope 342. The microscope 342 is arranged in a direction in which the lower stage unit 360 is looked down. The microscope 342 illuminates the observation target by emitting illumination light from the objective lens.

  When the alignment unit 300 is in the state shown in the figure, the microscopes 342 and 344 observe the surface of the substrate 180 mounted on the lower stage unit 360 or the upper stage unit 320, respectively. Thereby, the microscopes 342 and 344 can be aligned with the position of each wafer mark M on the substrate 180.

  FIG. 5 is a diagram illustrating the operation of the alignment unit 300. As shown in the figure, the lower stage portion 360 moves in the X direction. Here, by making the amount of movement of the lower stage portion 360 the same as the distance between the center of the lower stage portion 360 and the center of the microscope 344 that are known in advance, the alignment mark M of the substrate 180 is on one vertical line. Arranged. Thus, the pair of substrates 180 held by the lower stage unit 360 and the upper stage unit 320 are aligned.

  FIG. 6 is a diagram illustrating another operation of the alignment unit 300. As shown in the drawing, the piston 359 is raised in a state where the lower stage portion 360 is fixed at the position shown in FIG. As a result, the lower stage portion 360 is raised, and the substrates 180 are in close contact with each other. Furthermore, the substrates 180 are temporarily joined to each other by increasing the pressure for raising the piston 359. Hereinafter, as described with reference to FIG. 2d, the substrate holder 190 and the fastener 192 are transported to the pressurizing unit 240 while maintaining the temporarily bonded state of the substrate 180, whereby the aligned pair of substrates 180 is obtained. Join permanently.

  In the above example, the structure in which the upper stage unit 320 is fixed and the lower stage unit 360 is moved has been described. However, the lower stage unit 360 may be fixed and the upper stage unit 320 may be moved. In the case of such a structure, the microscope unit 390 is arranged so as to move together with the upper stage unit 320.

  Further, the upper stage unit 320 and the lower stage unit 360 may be moved together. In this case, the upper stage unit 320 and the microscope unit 390, and the lower stage unit 360 and the microscope unit 380 are moved together. That is, in the alignment unit 300, the upper stage unit 320 and the microscope unit 390, the lower stage unit 360, and the microscope unit 380 are required to be arranged at fixed relative positions.

  FIG. 7 is a cross-sectional view showing the structure of the light source unit 382 of the microscope unit 380. FIG. 8 is a schematic cross-sectional view of the light source unit 382 shown in FIG. However, FIG. 8 is merely a schematic cross-sectional view and does not correspond to the specific horizontal cross-section of FIG.

  The light source unit 382 includes a light emitting element 430, a radiator 440, a collimating lens 460, and a light source unit case 410 that accommodates them. The light source unit case 410 that forms a hollow housing has an emission port 416 that joins the incident end of the light guide 384 on one side surface (left side in the drawing). A ferrule 450 that holds the incident end of the light guide 384 is inserted into the emission port 416. The emission port 416 and the ferrule 450 are tightly adhered to each other.

  A collimator lens 460 is disposed in the vicinity of the incident end face of the light guide 384 inside the light source unit case 410. The collimator lens 460 is held between the emission surface of the light emitting element 430 and the incident end of the light guide 384 by a lens holder 418 protruding inward from the inner wall of the light source unit case 410. Accordingly, the illumination light emitted from the light emitting element 430 is efficiently injected into the light guide 384.

  A pair of supply ports 412 and 422 to which a coolant is supplied from the outside are disposed on the upper surface of the light source unit case 410. One supply port 412 supplies the refrigerant into the light source unit case 410. The other supply port 422 supplies the refrigerant directly into the radiator case 420 described later.

  A pair of discharge ports 414 and 424 are arranged on the other side surface (right side in the drawing) of the light source unit case 410. One discharge port 414 discharges the refrigerant from the light source unit case 410. The other discharge port 424 discharges the refrigerant directly from the inside of the radiator case 420 to the outside.

  The light emitting element 430 is mounted on a substrate 432 connected to a power source or the like. A heat radiator 440 is attached to the back surface of the substrate 432 in contact with the light emitting element 430 over a wide area. Accordingly, the heat radiator 440 efficiently transmits the heat generated from the light emitting element 430 through the substrate 432 without interfering with the illumination light emitted from the light emitting element 430.

  The radiator 440 is further accommodated in the radiator case 420 inside the light source unit case 410. The radiator 440 is a chimney-type heat sink having a plurality of vertically radiating holes, and a supply port 422 opens above the radiator 440 in the radiator case 420. In addition, a discharge port 424 opens below the radiator 440. Therefore, the refrigerant supplied from the supply port 422 is discharged from the discharge port 424 while cooling the radiator 440 and does not flow to other regions inside the light source unit case 410.

  The light emitting element 430 and the radiator 440 do not directly contact the light source unit case 410. Therefore, the heat generated in the light emitting element 430 is dissipated exclusively from the radiator 440.

  As the light emitting element 430, a light emitting diode with high light emission efficiency and small calorific value can be preferably exemplified. In particular, a surface light emitting diode that emits light from a plane parallel to the active layer can efficiently inject illumination light into the light guide 384 having the incident surface facing each other. Other light emitting elements 430 such as an organic EL element may be used.

  Since these light emitting elements 430 have high luminous efficiency, they generate little heat. However, fever is not completely absent. Therefore, it is preferable to eliminate the influence of slight heat generation as the illumination light source of the microscopes 342 and 344 used for precise alignment.

  Therefore, the alignment unit 300 may be controlled to cause the light emitting element 430 to emit light only during a period in which the microscopes 342 and 344 are used in the alignment operation and to be extinguished during other periods. Accordingly, power consumption of the light emitting element 430 can be suppressed, and the amount of heat generated from the light emitting element 430 can be suppressed. A light-emitting diode having a short time from start-up to steady light emission can be preferably used from this point of view.

  In addition, when the heat generation of the light-emitting element 430 is small as described above, the amount of refrigerant that is flowed for cooling can be reduced. Thereby, the vibration which arises when flowing a refrigerant | coolant can also be reduced and alignment accuracy can be improved further.

  In the light source unit 382 as described above, the light emitting element 430 is disposed between the supply port 412 and the discharge port 414. Further, as indicated by a dotted line in FIG. 8, the supply port 412 is opened immediately above the light emitting element 430. Accordingly, the refrigerant supplied from the supply port 412 to the inside of the light source unit case 410 first flows in front of the light emitting element 430. Subsequently, the refrigerant that has flowed around the light emitting element 430 is discharged from the discharge port 414.

  Accordingly, the portion where the flow rate of the refrigerant flow is high touches the light emitting element 430, and the light emitting element 430 is efficiently cooled. In addition, the refrigerant heated by the heat generated by the radiator 440 is discharged to the outside of the light source unit case 410 from the discharge port 414 without coming into contact with other members. Therefore, the influence of heat generated by the light emitting element 430 does not affect the optical elements such as the collimating lens 460, for example.

  Further, as already described, the refrigerant that has contacted the radiator 440 is discharged from the discharge port 414 without traversing the optical path of the illumination light. This prevents the refrigerant whose refractive index has been changed by being heated from shaking the illumination light. Note that, when the alignment mark 184 illuminated by the swaying illumination light is observed with the microscope 344, the alignment accuracy is not preferable.

  A preferable example of the refrigerant is pressurized dry air supplied to the alignment unit 300. That is, dry air is supplied to the drive unit 350 and the like of the alignment unit 300 as a working fluid and a laminar flow for lubrication. Therefore, by partially branching the path of the pressurized air and coupling it to the supply ports 412 and 422, the dried and temperature-controlled air can be injected into the light source unit case 410 and the radiator case 420 as a refrigerant.

  The driving unit 350 of the lower stage unit 360 that moves in the alignment unit 300 is supplied with pressurized dry air as a working fluid and as a laminar flow for lubrication. Therefore, it is possible to supply pressurized air to the light source unit 382 by providing a minimum branch path. Further, since the dry air as the working fluid is pressurized, the refrigerant can be circulated without adding a pressurizing pump or the like by coupling the discharge ports 414 and 424 to the relatively low pressure region. .

  Although the structure of the light source unit 382 has been described so far, the above structure may be applied to the light source unit 392 of the microscope unit 390. Thereby, the accuracy of position measurement by both the microscope units 380 and 390 can be maintained, and accurate alignment can be executed in the alignment unit 300.

  FIG. 9 is a cross-sectional view showing another structure of the light source unit 382. Except for the part described below, the light source unit 382 shown in FIGS. 7 and 8 and the light source unit 382 shown in FIG. 9 have the same structure. Therefore, common elements are denoted by the same reference numerals, and redundant description is omitted.

  The light source unit 382 has a unique structure in that a supply port 412 is opened between the incident end of the light guide 384 and the collimator lens 460. In addition, the lens holder 418 has a unique structure in that a path parallel to the paper surface is provided for the purpose of forming a path through which the coolant flows from the light guide 384 side to the light emitting element 430 side of the collimator lens 460.

  With such a structure, the refrigerant injected from the supply port 412 can make the entire optical system from the light emitting element 430 to the incident end of the light guide 384 constant at the initial temperature of the air just supplied. In addition, since the refrigerant flows through the entire interior of the light source unit case 410, the temperature of the entire light source unit case 410 becomes uniform, and when a temperature gradient occurs, it becomes gentle.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The order of execution of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that the output can be realized in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the description, and the drawings, even if it is described using “first”, “next”, etc. for convenience, it does not mean that it is essential to carry out in this order. Absent.

1 is a plan view schematically showing the structure of a multilayer substrate manufacturing system 100. FIG. It is a figure which shows typically the transition of the state of the board | substrate 180. FIG. It is a figure which shows typically the transition of the state of the board | substrate 180. FIG. It is a figure which shows typically the transition of the state of the board | substrate 180. FIG. It is a figure which shows typically the transition of the state of the board | substrate 180. FIG. It is a figure which shows typically the transition of the state of the board | substrate 180. FIG. It is a figure which shows the form of the alignment mark 184 typically. 4 is a cross-sectional view schematically showing a mechanical structure of alignment unit 300. FIG. FIG. 6 is a diagram illustrating an operation of the alignment unit 300. FIG. 10 is a diagram illustrating another operation of the alignment unit 300. 4 is a cross-sectional view showing a structure of a light source unit 382. FIG. It is typical sectional drawing of the light source part 382 shown in FIG. It is sectional drawing which shows the other structure of the light source part 382 typically.

Explanation of symbols

100 multilayer substrate manufacturing system, 101 housing, 102 room temperature section, 110, 120 substrate cassette, 130, 230 heat insulation wall, 150, 250 shutter, 160 robot arm, 180 substrate, 182 notch, 184 alignment mark, 186 element area, 190 Substrate holder, 191 groove, 192 fastener, 202 high temperature part, 240 pressure part, 300 alignment part, 310 frame, 312 top plate, 314 support, 316 bottom plate, 320 upper stage part, 342, 344 microscope, 350 drive part , 352 Guide rail, 354 X drive unit, 356 Y drive unit, 358 cylinder, 359 piston, 360 lower stage unit, 372, 374 reflector, 380, 390 microscope unit, 382, 392 light source unit, 384, 394, 398 light Id, 396 relay unit, 410 light source unit case, 412, 422 supply port, 414, 424 discharge port, 416 exit port, 418 lens holder, 420 radiator case, 430 light emitting element, 432 substrate, 440 radiator, 450 ferrule, 460 Collimating lens

Claims (14)

An alignment apparatus for aligning two substrates to be superimposed,
A first stage for holding one of the two substrates;
A second stage that holds and moves the other of the two substrates;
A drive unit for driving the second stage;
An observation unit that moves with the second stage by the driving unit and observes the one substrate;
An illuminating unit having a light source that moves with the second stage by the driving unit and generates illumination light that illuminates an observation target region of the observing unit;
An alignment apparatus comprising: an optical waveguide that moves together with the second stage by the driving unit and guides the illumination light generated by the light source to the observation unit.   The alignment apparatus according to claim 1, wherein the observation unit and the illumination unit are provided on the second stage, respectively.   The alignment apparatus according to claim 1, further comprising a heat dissipating unit for releasing heat generated from the illumination unit. The heat dissipation means is
A radiator disposed in contact with the light source;
The alignment apparatus according to claim 3, further comprising: a radiator case that accommodates at least a part of the radiator and circulates a refrigerant therein. The illumination unit is
An optical system that guides the illumination light from the light source to the optical waveguide; and an outer case that covers a periphery of the light source, the optical system, and the radiator case, and the heat dissipation means is a system different from the radiator case. The alignment apparatus according to claim 4, wherein a refrigerant is circulated through the outer case.   The alignment apparatus according to claim 5, wherein the heat radiating unit includes a refrigerant supply port that is provided in the outer case and supplies the refrigerant to an optical path of the illumination light from the light source to the optical waveguide.   The alignment apparatus according to claim 6, wherein the coolant supply port is opened to supply the coolant between the optical waveguide and the optical system.   The alignment apparatus according to claim 5, wherein the refrigerant is a fluid supplied to the driving unit, and a flow path of the fluid is connected to the radiator case and the outer case. .   The alignment apparatus according to claim 8, wherein the fluid is pressurized air.   The said illumination part is further equipped with the control part which turns on the said light source in the period when the said observation part images the said board | substrate, and turns off the said light source in the period when the said observation part is not imaging the said board | substrate. Item 10. The alignment device according to any one of Items 9 to 9.   The alignment apparatus according to claim 1, wherein the light source includes a light emitting diode.   12. The alignment apparatus according to claim 1, wherein the illumination unit includes a light source unit case that houses the light source and has an emission port coupled to an incident end of the optical waveguide.   A substrate bonding apparatus comprising the alignment apparatus according to any one of claims 1 to 12, and bonding the two substrates aligned by the alignment apparatus. An alignment step of aligning two substrates using the alignment apparatus according to any one of claims 1 to 12,
And a bonding step of bonding the two substrates aligned in the alignment step to each other.

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