WO2016132694A1 - Semiconductor device production method - Google Patents

Semiconductor device production method Download PDF

Info

Publication number
WO2016132694A1
WO2016132694A1 PCT/JP2016/000553 JP2016000553W WO2016132694A1 WO 2016132694 A1 WO2016132694 A1 WO 2016132694A1 JP 2016000553 W JP2016000553 W JP 2016000553W WO 2016132694 A1 WO2016132694 A1 WO 2016132694A1
Authority
WO
WIPO (PCT)
Prior art keywords
substrate
hydrogen gas
hermetic chamber
generated
insulating film
Prior art date
Application number
PCT/JP2016/000553
Other languages
French (fr)
Japanese (ja)
Inventor
早川　裕
久則 与倉
Original Assignee
株式会社デンソー
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2015242400A external-priority patent/JP6341190B2/en
Application filed by 株式会社デンソー filed Critical 株式会社デンソー
Priority to CN201680006742.2A priority Critical patent/CN107209078B/en
Priority to US15/528,124 priority patent/US9944515B2/en
Publication of WO2016132694A1 publication Critical patent/WO2016132694A1/en

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
    • B81C3/00—Assembling of devices or systems from individually processed components
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C19/00—Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
    • G01C19/56—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
    • G01C19/5783—Mountings or housings not specific to any of the devices covered by groups G01C19/5607 - G01C19/5719
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/84—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by variation of applied mechanical force, e.g. of pressure

Definitions

  • the present disclosure relates to a method for manufacturing a semiconductor device in which a first substrate and a second substrate are joined so that an airtight chamber is formed between the first substrate and the second substrate.
  • the following has been proposed as a semiconductor device in which an airtight chamber is configured between a first substrate and a second substrate (see, for example, Patent Document 1). That is, in this semiconductor device, a sensing unit that detects angular velocity is formed on the first substrate. In addition, the second substrate has a recess formed in a portion of one surface of the first substrate facing the sensing unit. And this 2nd board
  • the hermetic chamber is at a vacuum pressure.
  • Such a semiconductor device is manufactured as follows. That is, first, a sensing unit that detects angular velocity is formed on the first substrate, and a recess is formed on the second substrate. And it manufactures by joining a 1st board
  • OH groups are formed on the bonding surfaces of the first substrate and the second substrate, and the bonding strength is improved by covalently bonding the OH groups on each bonding surface. It has been known. However, in such a bonding method, although the bonding strength between the first substrate and the second substrate can be improved, hydrogen gas (that is, degas) is generated in the hermetic chamber by the OH group, and the pressure of the hermetic chamber is generated by the hydrogen gas. Is higher than the desired pressure.
  • hydrogen gas that is, degas
  • the hydrogen gas is diffused (ie, passed through the first substrate or the second substrate) by increasing the diffusion distance (ie, diffusion coefficient) of the hydrogen gas in the hermetic chamber by performing heat treatment. ) To be discharged outside.
  • this heating step is simply performed, the pressure in the hermetic chamber may not be a desired pressure. That is, the pressure in the hermetic chamber may fluctuate.
  • the airtight chamber is formed by joining the first substrate and the second substrate, and the airtight chamber is used as a reference pressure. The same occurs in a pressure sensor or the like serving as a chamber.
  • An object of the present disclosure is to provide a method for manufacturing a semiconductor device capable of suppressing fluctuations in pressure in an airtight chamber.
  • a first substrate having one surface, one surface and the other surface opposite to the one surface, a recess is formed on the one surface side, and the one surface faces one surface of the first substrate.
  • a second substrate bonded to the first substrate in a state, and a hermetic chamber is formed including a space between the first substrate and the recess of the second substrate, and the hermetic chamber is vacuumed
  • the first substrate containing silicon is prepared, and the second substrate containing silicon is prepared by forming the depression on the one surface of the second substrate.
  • OH groups generated on the one surface of the first substrate and OH groups generated on the one surface of the second substrate are covalently bonded.
  • the heat treatment by heating at a temperature rising rate of 1 ° C./sec or less so that the portion where the OH group is generated in the first substrate and the second substrate is 700 ° C. or more.
  • an OH group is generated on the first substrate and the second substrate, the first substrate and the second substrate are joined, and then the hermetic chamber is heated at a rate of 1 ° C./sec or less. Is heated so that the wall surface constituting the temperature becomes 700 ° C. or higher. Thereby, all the OH groups remaining in the hermetic chamber can be converted into hydrogen gas. Since the heating temperature and the heating time are adjusted so that the diffusion distance of the hydrogen gas is equal to or greater than the distance between the bottom surface of the recess in the second substrate and the other surface of the second substrate, the hydrogen gas is removed. It can be discharged from a closed room. For this reason, the pressure in an airtight chamber can be made into a desired pressure, and it can suppress that the pressure in an airtight chamber fluctuates.
  • FIG. 1 is a cross-sectional view of a pressure sensor according to a first embodiment of the present disclosure.
  • 2 (a) to 2 (d) are cross-sectional views showing the manufacturing process of the pressure sensor shown in FIG.
  • FIG. 3A to FIG. 3C are cross-sectional views showing the manufacturing process of the pressure sensor following FIG.
  • FIG. 4 is a diagram showing the relationship between the amount of hydrogen gas generated and the sample surface temperature.
  • FIG. 5 is a diagram showing the relationship between the heating temperature and the pressure in the hermetic chamber
  • FIG. 6 is a cross-sectional view of a pressure sensor according to a second embodiment of the present disclosure.
  • FIG. 1 is a cross-sectional view of a pressure sensor according to a first embodiment of the present disclosure.
  • 2 (a) to 2 (d) are cross-sectional views showing the manufacturing process of the pressure sensor shown in FIG.
  • FIG. 3A to FIG. 3C are cross-sectional views showing the manufacturing process of the pressure sensor following FIG.
  • FIG. 4
  • FIG. 7 is a cross-sectional view of a pressure sensor according to another embodiment of the present disclosure
  • FIG. 8 is a cross-sectional view of a pressure sensor according to another embodiment of the present disclosure
  • FIG. 9 is a cross-sectional view of a pressure sensor according to another embodiment of the present disclosure.
  • the pressure sensor includes a first substrate 10 having one surface 10a and another surface 10b.
  • the first substrate 10 is configured by an SOI (Silicon on Insulator) substrate in which a support substrate 11, an insulating film 12, and a semiconductor layer 13 are sequentially stacked. Then, one surface 10a of the first substrate 10 is formed on one surface of the semiconductor layer 13 opposite to the insulating film 12 side, and the first substrate is formed on one surface of the support substrate 11 opposite to the insulating film 12 side.
  • the other surface 10b of 10 is comprised.
  • the support substrate 11 and the semiconductor layer 13 are made of a silicon substrate or the like, and the insulating film 12 is made of SiO 2 or SiN.
  • the diaphragm part 15 is comprised in the 1st board
  • the recess 14 is formed so as to reach the insulating film 12 from the other surface 10 b of the first substrate 10.
  • the diaphragm portion 15 is configured by the insulating film 12 and the semiconductor layer 13 located between the bottom surface of the recess 14 and the one surface 10 a of the first substrate 10.
  • each gauge resistor 16 is appropriately connected by a connection wiring layer (not shown) so as to form a bridge circuit.
  • the gauge resistor 16 is a diffusion layer configured by heat treatment after impurities are ion-implanted.
  • the surface concentration of impurities constituting the gauge resistor 16 is set to 1.0 ⁇ 10 ⁇ 18 to 1.0 ⁇ 10 ⁇ 21 cm ⁇ 3, and the gauge resistor 16 is diffused according to the present disclosure.
  • a lead wiring layer or the like that is connected to the first substrate 10 as appropriate with each gauge resistor 16 and connected to an external circuit through a through electrode (not shown) formed on the second substrate 20. Is also formed.
  • the second substrate 20 is disposed on the one surface 10a of the first substrate 10 as described above.
  • the second substrate 20 includes a bonded substrate 21 and an insulating film 22 formed on the one surface 21 a side facing the first substrate 10 of the bonded substrate 21.
  • 20a is constituted by one surface of the insulating film 22 opposite to the bonded substrate 21 side.
  • the bonded substrate 21 is made of a silicon substrate or the like, and the insulating film 22 is made of SiO 2 or SiN.
  • the other surface 20 b of the second substrate 20 is configured by the other surface 21 b on the opposite side to the one surface 21 a of the bonded substrate 21.
  • a recess 21c is formed at a portion facing the gauge resistor 16, and the insulating film 22 is also formed on the wall surface of the recess 21c.
  • a recess 20 c formed by the insulating film 22 formed on the wall surface of the recess 21 c is formed in a portion facing the gauge resistor 16.
  • the recess 20c has a regular octagonal planar shape, and the length of the diagonal line passing through the center is 350 ⁇ m.
  • the recess 20c is configured such that the distance between the bottom surface of the recess 20c and the other surface 20b of the second substrate 20 is 10 to 200 ⁇ m.
  • the second substrate 20 has one surface 20a (that is, the insulating film 22) joined to one surface 10a (that is, the semiconductor layer 13) of the first substrate 10.
  • the hermetic chamber 30 is formed between the first substrate 10 and the second substrate 20 by the recess 20 c, and the gauge resistor 16 is sealed in the hermetic chamber 30.
  • the airtight chamber 30 since a predetermined pressure is applied from the airtight chamber 30 to the one surface 10a side of the diaphragm portion 15, the airtight chamber 30 functions as a reference pressure chamber.
  • the first substrate 10 and the second substrate 20 are so-called direct bonding that activates and bonds the bonding surfaces of the first substrate 10 and the second substrate 20 as will be described later. It is joined.
  • the second substrate 20 is formed with a through-hole that penetrates in the stacking direction of the first substrate 10 and the second substrate 20 and exposes the lead wiring layer formed in the first substrate 10.
  • a through electrode is formed so as to be appropriately electrically connected to the lead wiring layer and to be connected to an external circuit.
  • a first substrate 10 in which a support substrate 11, an insulating film 12, and a semiconductor layer 13 are sequentially laminated is prepared. Then, after forming a mask (not shown) on one surface 10a, an impurity is ion-implanted and heat treatment is performed to thermally diffuse the impurity, thereby appropriately forming a gauge resistor 16, a connection wiring layer (not shown), a lead-out wiring layer, and the like. Note that the heat treatment in this step is performed, for example, by heat-treating the first substrate 10 at 800 to 1100 ° C. so that impurities are thermally diffused.
  • a bonded substrate 21 is prepared as shown in FIG. 2B, and a recess 21c is formed on one surface 21a of the bonded substrate 21 by dry etching or the like.
  • the insulating film 22 is formed on the one surface 21a of the substrate 21 by a chemical vapor deposition (ie, chemical vapor deposition (CVD)) method or the like.
  • CVD chemical vapor deposition
  • the first substrate 10 semiconductor layer 13
  • the second substrate 20 insulating film 22
  • OH groups are generated on the one surface 10 a side of the first substrate 10 and the one surface 20 a side of the second substrate 20.
  • the first substrate 10 and the second substrate 20 are disposed in a chamber (not shown), and the one surface 10a (that is, the semiconductor layer 13) side of the first substrate 10 and the one surface 20a (that is, insulating) of the second substrate 20 are disposed.
  • Irradiation with O 2 plasma, N 2 plasma, Ar ion beam or the like is performed from the film 22) side to remove impurities adhering to the bonding surface and to activate each bonding surface.
  • the activation of the bonding surface means that a part of the bond in the atom exposed on the bonding surface has lost the bonding partner. Further, when the bonding surface is activated, O 2 plasma or the like is irradiated from the one surface 10a side of the first substrate 10 and the one surface 20a side of the second substrate 20, so that the second substrate on the one surface 10a of the first substrate 10 is activated. The region on the inner edge side of the region bonded to 20, the wall surface of the recess 20 c of the second substrate 20, and the like are also activated.
  • OH groups are generated on the one surface 10 a side of the first substrate 10 and the one surface 20 a side of the second substrate 20.
  • the OH group is generated in the activated region of the first substrate 10 and the second substrate 20, the region closer to the inner edge than the region bonded to the second substrate 20 on the one surface 10 a of the first substrate 10. , And on the wall surface of the recess 20c of the second substrate 20 and the like. Further, when generating OH groups on the surfaces 10a and 20a of the first substrate 10 and the second substrate 20, instead of taking out the first substrate 10 and the second substrate 20 from the chamber, for example, in the chamber OH groups may be generated on the first substrate 10 and the second substrate 20 by introducing the atmosphere.
  • alignment is performed by an infrared microscope or the like using alignment marks or the like appropriately provided on the first substrate 10 and the second substrate 20, and at a low temperature of room temperature to 550 ° C.
  • the first substrate 10 and the second substrate 20 are bonded by so-called direct bonding.
  • the first substrate 10 and the second substrate 20 are directly bonded by applying a weight of 18 kN in the stacking direction of the first substrate 10 and the second substrate 20 while maintaining the temperature at 300 ° C.
  • the hermetic chamber 30 is formed including the space between the first substrate 10 and the recessed portion 20 c of the second substrate 20, and the gauge resistor 16 is sealed in the hermetic chamber 30.
  • hydrogen gas 31 is generated by the covalent bonding of OH groups generated on one surface 10a of the first substrate 10 and one surface 20a of the second substrate 20. To do.
  • the process up to the process of FIG. 2D is introduced into an annealing apparatus (not shown) and heat-treated.
  • the OH group that has not contributed to the bonding between the first substrate 10 and the second substrate 20, that is, the region on the inner edge side of the region bonded to the second substrate 20 on the one surface 10 a of the first substrate 10 is generated.
  • the OH groups and the OH groups generated on the wall surface of the recess 20c of the second substrate 20 are bonded to each other to generate water molecules.
  • FIG. 4 shows experimental results obtained by performing a thermal desorption spectroscopy (TDS) method after generating OH groups by irradiating O 2 plasma, and the rate of temperature increase. Is 1 ° C./sec.
  • the sample surface temperature in FIG. 4 is the surface temperature at which OH groups are generated, and the background indicated by the broken line in FIG. 4 is noise specific to the apparatus used in the experiment.
  • the temperature at which hydrogen gas is not generated shifts to a low temperature side when the temperature rising rate is lower than 1 ° C./sec, and hydrogen gas is not generated when the temperature rising rate is higher than 1 ° C./sec. It is known that the temperature shifts to the high temperature side. Further, as shown in FIG. 4, when the plasma humidity is changed, the present inventors change the maximum amount of hydrogen gas generated and the temperature at the maximum amount, but the temperature at which hydrogen gas is not generated. Also found no change.
  • the heating rate is set to 1 ° C./sec or less, and heating is performed so that the surface on which the OH group is generated is 700 ° C. or more. That is, the heating is performed so that the one surface 10a of the first substrate 10, the one surface 20a of the second substrate 20, and the wall surface of the recess 20c are 700 ° C. or higher.
  • FIG.3 (b) has shown the state before the surface in which the OH group was produced
  • OH groups generated on the bonding surfaces of the first substrate 10 and the second substrate 20 react as shown in the above reaction formula [F1]. May remain.
  • the bonding surface of the first substrate 10 and the second substrate 20 is heated so as to be 700 ° C. or higher, so that no reaction occurs in the process of FIG. In the case where an OH group is present, the OH group can be converted into hydrogen gas 31.
  • a gas that maintains the heating temperature that is, a temperature of 700 ° C. or higher
  • a blanking process is performed.
  • the diffusion distance of the hydrogen gas 31 is proportional to the diffusion coefficient (D) and the heating time (t) (that is, 2 (Dt) 1/2 ), and the diffusion coefficient (D) is proportional to the heating temperature. To do. That is, the diffusion distance of the hydrogen gas 31 is proportional to the heating time and the heating temperature.
  • the inventors diffuse (i.e., pass through) the portion that becomes the shortest distance between the wall surface that forms the hermetic chamber 30 and the wall surface that is exposed to the outside air, and discharge the hydrogen gas 31.
  • Experiments were conducted by adjusting the heating temperature and the heating time so that the diffusion distance of the hydrogen gas 31 was a distance equal to or longer than the shortest distance and the diffusion distance was constant, and the experimental results shown in FIG. 5 were obtained.
  • the shortest distance between the wall surface constituting the hermetic chamber 30 and the wall surface exposed to the outside air is the portion between the bottom surface of the recess 20c and the other surface 20b of the second substrate 20. Become.
  • the volume in the hermetic chamber 30 is 1.0 ⁇ 10 ⁇ 3 mm ⁇ 3 and the distance between the bottom surface of the recess 20c and the other surface 20b of the second substrate 20 is 10 to 200 ⁇ m. It is a figure at the time of temperature rising rate being 1 degree-C / sec.
  • a distance equal to or greater than the distance between the bottom surface of the recess 20c and the other surface 20b of the second substrate 20 is defined as a diffusion distance, and the diffusion distance is proportional to D 1/2 and t 1/2 . Therefore, even when the heating temperature (that is, the diffusion coefficient) and the heating time are adjusted so that the diffusion distance is constant, for example, when the heating temperature is 600 ° C., the pressure in the hermetic chamber 30 is sufficiently increased. It was found that the pressure could not be reduced. That is, it was found that when the heating temperature is 600 ° C., the hydrogen gas 31 in the hermetic chamber 30 cannot be sufficiently discharged.
  • D is a diffusion coefficient
  • t is a heating time.
  • the heating temperature is 600 ° C.
  • the diffusion time of the hydrogen gas 31 is set to the bottom surface of the recess 20 c and the other surface of the second substrate 20 by setting the heating time to a long time of 75 hours. It is set as more than the distance between 20b.
  • the hermetic chamber 30 is adjusted by adjusting the heating temperature and the heating time so that the diffusion distance is equal to or greater than the distance between the bottom surface of the recess 20c and the other surface 20b of the second substrate 20.
  • the hydrogen gas 31 generated inside can be discharged from the hermetic chamber 30, and the pressure in the hermetic chamber 30 can be set to a desired pressure.
  • the shortest distance between the wall surface configuring the airtight chamber 30 and the wall surface exposed to the outside air is the bottom surface of the recess 20c and the other surface 20b of the second substrate 20.
  • FIG. 3C shows a state in which the hydrogen gas 31 is discharged through a portion between the bottom surface of the recess 20c and the other surface 20b of the second substrate 20.
  • hydrogen gas 31 is discharged by diffusing a portion between one surface 10a and the other surface 10b of the first substrate 10.
  • the heating step is preferably performed at less than 1412 ° C.
  • the diffusion distance of the hydrogen gas 31 is proportional to the heating temperature and the heating time. For this reason, for example, after heating the surface on which OH groups are generated in the step of FIG. 3B to be 700 ° C. or higher, the temperature is lowered to 600 ° C. in the step of FIG. By increasing the length, the diffusion distance may be greater than or equal to the distance between the bottom surface of the recess 20c and the other surface 20b of the second substrate 20.
  • the pressure sensor shown in FIG. 1 is manufactured by forming a mask on the other surface 10b of the first substrate 10 and forming the concave portion 14 by dry etching or the like to form the diaphragm portion 15.
  • OH groups are generated on the one surface 10a side of the first substrate 10 and the one surface 20a side of the second substrate 20, and the first substrate 10 and the second substrate 20 are bonded. . And it heats so that the temperature increase rate shall be 1 degrees C / sec or less, and the surface in which the OH group is produced
  • the heating temperature and the heating time are adjusted so that the diffusion distance of the hydrogen gas 31 is equal to or greater than the distance between the bottom surface of the recess 20c and the other surface 20b of the second substrate 20.
  • the hydrogen gas 31 in the hermetic chamber 30 can be sufficiently discharged, and the inside of the hermetic chamber 30 can be sufficiently decompressed (that is, a vacuum state). That is, it can suppress that the pressure in the airtight chamber 30 fluctuates.
  • the first substrate 10 is configured to have a thin insulating film 17 on the semiconductor layer 13. That is, the first substrate 10 is configured by laminating the support substrate 11, the insulating film 12, the semiconductor layer 13, and the thin insulating film 17 in this order, and one surface 10 a of the thin insulating film 17 on the side opposite to the semiconductor layer 13 side. It consists of one side.
  • the diaphragm portion 15 includes an insulating film 12, a semiconductor layer 13, and a thin insulating film 17 positioned between the bottom surface of the recess 14 and the one surface 10 a of the first substrate 10.
  • Such a pressure sensor is manufactured as follows. That is, first, in the process of FIG. 2A, after forming the gauge resistor 16 and the like, the first substrate 10 is configured by forming the thin insulating film 17 on the semiconductor layer 13 by, for example, thermal oxidation. . Thereafter, the steps after FIG. 2B are performed, and when the heating step after FIG. 3A is performed, the heat treatment is performed in a state where the thin insulating film 17 is formed on the semiconductor layer 13, The pressure sensor is manufactured.
  • the degassing process is performed with the thin insulating film 17 formed on the semiconductor layer 13.
  • the thin insulating film 17 can suppress the outward diffusion (out diffusion) in which the impurities constituting the gauge resistor 16 diffuse into the hermetic chamber 30, and the characteristics of the gauge resistor 16 change. Can be suppressed.
  • the bonding strength may be lowered if the thin insulating film 17 is thick. For this reason, it is preferable to form the thin insulating film 17 to be about 10 nm or less.
  • the present disclosure can be applied to manufacturing methods of various semiconductor devices that include the hermetic chamber 30 and the pressure of the hermetic chamber 30 is in a vacuum state, and can also be applied to manufacturing methods of angular velocity sensors and the like. it can.
  • the present disclosure may be applied to a method for manufacturing a pressure sensor in which the second substrate 20 includes only the bonded substrate 21.
  • the recessed portion 20c of the second substrate 20 is configured by the recessed portion 21c of the bonded substrate 21, and the portion located between the bottom surface of the recessed portion 20c and the other surface 20b of the second substrate 20 is Only the bonded substrate 21 is provided.
  • the insulating film 22 may not be formed on the wall surface of the recess 21c.
  • the first substrate 10 is composed only of the support substrate 11, and the bonded substrate 21 and the insulation positioned between the bottom surface of the recess 20 c and the other surface 20 b of the second substrate 20.
  • the present disclosure may be applied to a method of manufacturing a pressure sensor in which the membrane 22 is the diaphragm portion 15 and the gauge resistor 16 is formed on the diaphragm portion 15.
  • the manufacturing of the pressure sensor in which the first substrate 10 is configured by the support substrate 11 and the insulating film 12, and the second substrate 20 is configured only by the bonded substrate 21.
  • the present disclosure may be applied to a method.
  • the recessed portion 20 c of the second substrate 20 is configured by the recessed portion 21 c of the bonded substrate 21, and the bottom surface of the recessed portion 20 c and the second substrate 20 The portion located between the surface 20 b is only the bonded substrate 21.
  • the diaphragm portion 15 may be composed of only the semiconductor layer 13. That is, the insulating film 12 may be removed by the recess 14. Similarly, in the second embodiment, the diaphragm portion 15 may be composed of the semiconductor layer 13 and the thin insulating film 17.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Ceramic Engineering (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Computer Hardware Design (AREA)
  • Pressure Sensors (AREA)

Abstract

A semiconductor device production method in which a vacuum airtight chamber (30) is formed between a first substrate (10) and a recessed part (20c) of a second substrate (20) is provided with: the preparation of the first substrate and the second substrate, which include silicon; the joining of the first and second substrates; heat treatment for discharging hydrogen gas (31) within the airtight chamber; and the generation, before the joining, of OH groups on the wall surface of the recessed part of the first and second substrates. In the joining, the OH groups of the first and second substrates are covalently bonded. In the heat treatment, at a rate of temperature rise of 1°C/sec or less, the portions of the first and second substrates where OH groups are generated are heated so as to become 700°C or greater, hydrogen gas is generated, the heating temperature and heating time are adjusted so that the diffusion length of the hydrogen gas is greater than or equal to the minimum distance between the wall surface of the airtight chamber and outside air, and the hydrogen gas is discharged from the airtight chamber.

Description

半導体装置の製造方法Manufacturing method of semiconductor device 関連出願の相互参照Cross-reference of related applications
　本出願は、２０１５年２月１６日に出願された日本特許出願番号２０１５－２７７３８号および２０１５年１２月１１日に出願された日本特許出願番号２０１５―２４２４００号に基づくもので、ここにその記載内容を援用する。 This application is based on Japanese Patent Application No. 2015-27738 filed on Feb. 16, 2015 and Japanese Patent Application No. 2015-242400 filed on Dec. 11, 2015. Incorporate content.
　本開示は、第１基板と第２基板との間に気密室が構成されるように第１基板と第２基板とを接合してなる半導体装置の製造方法に関するものである。 The present disclosure relates to a method for manufacturing a semiconductor device in which a first substrate and a second substrate are joined so that an airtight chamber is formed between the first substrate and the second substrate.
　従来より、第１基板と第２基板との間に気密室が構成された半導体装置として、次のものが提案されている（例えば、特許文献１参照）。すなわち、この半導体装置では、第１基板に角速度を検出するセンシング部が形成されている。また、第２基板は、第１基板の一面のうちのセンシング部と対向する部分に窪み部が形成されている。そして、この第２基板は、第１基板と窪み部との間を含む空間にてセンシング部を封止する気密室が構成されるように、第１基板に接合されている。なお、気密室は真空圧とされている。 Conventionally, the following has been proposed as a semiconductor device in which an airtight chamber is configured between a first substrate and a second substrate (see, for example, Patent Document 1). That is, in this semiconductor device, a sensing unit that detects angular velocity is formed on the first substrate. In addition, the second substrate has a recess formed in a portion of one surface of the first substrate facing the sensing unit. And this 2nd board | substrate is joined to the 1st board | substrate so that the airtight chamber which seals a sensing part in the space containing between a 1st board | substrate and a hollow part may be comprised. The hermetic chamber is at a vacuum pressure.
　このような半導体装置は、次のように製造される。すなわち、まず、第１基板に角速度を検出するセンシング部を形成すると共に、第２基板に窪み部を形成する。そして、第１基板と窪み部との間を含む空間にてセンシング部を封止する気密室が構成されるように、第１基板と第２基板とを接合することにより、製造される。 Such a semiconductor device is manufactured as follows. That is, first, a sensing unit that detects angular velocity is formed on the first substrate, and a recess is formed on the second substrate. And it manufactures by joining a 1st board | substrate and a 2nd board | substrate so that the airtight chamber which seals a sensing part in the space containing between a 1st board | substrate and a hollow part may be comprised.
　ところで、第１基板と第２基板との接合では、第１基板と第２基板の接合面にＯＨ基を形成し、各接合面のＯＨ基同士を共有結合させることで接合強度を向上させることが知られている。しかしながら、このような接合方法では、第１基板と第２基板との接合強度を向上できるものの、ＯＨ基によって気密室内に水素ガス（すなわち、デガス）が生成され、当該水素ガスによって気密室の圧力が所望の圧力より高くなるという問題がある。 By the way, in the bonding between the first substrate and the second substrate, OH groups are formed on the bonding surfaces of the first substrate and the second substrate, and the bonding strength is improved by covalently bonding the OH groups on each bonding surface. It has been known. However, in such a bonding method, although the bonding strength between the first substrate and the second substrate can be improved, hydrogen gas (that is, degas) is generated in the hermetic chamber by the OH group, and the pressure of the hermetic chamber is generated by the hydrogen gas. Is higher than the desired pressure.
　この問題を解決するため、加熱処理を行うことによって気密室内の水素ガスの拡散距離（すなわち、拡散係数）を大きくすることにより、水素ガスを第１基板または第２基板内を拡散（すなわち、通過）させて外部に排出することが考えられる。しかしながら、この加熱工程を単純に行うと、気密室内の圧力を所望の圧力にすることができない場合がある。つまり、気密室内の圧力が変動してしまう場合がある。 In order to solve this problem, the hydrogen gas is diffused (ie, passed through the first substrate or the second substrate) by increasing the diffusion distance (ie, diffusion coefficient) of the hydrogen gas in the hermetic chamber by performing heat treatment. ) To be discharged outside. However, if this heating step is simply performed, the pressure in the hermetic chamber may not be a desired pressure. That is, the pressure in the hermetic chamber may fluctuate.
　なお、このような問題は、センシング部を封止する気密室のみに発生する問題ではなく、例えば、第１基板と第２基板とを接合して気密室を構成し、当該気密室を基準圧力室とする圧力センサ等においても同様に発生する。 Such a problem is not a problem that occurs only in the airtight chamber that seals the sensing unit. For example, the airtight chamber is formed by joining the first substrate and the second substrate, and the airtight chamber is used as a reference pressure. The same occurs in a pressure sensor or the like serving as a chamber.
特開２０１２－１８７６６４号公報JP 2012-187664 A
　本開示は、気密室内の圧力が変動することを抑制できる半導体装置の製造方法を提供することを目的とする。 An object of the present disclosure is to provide a method for manufacturing a semiconductor device capable of suppressing fluctuations in pressure in an airtight chamber.
　本開示の態様において、一面を有する第１基板と、一面および前記一面と反対側の他面を有し、前記一面側に窪み部が形成され、当該一面が前記第１基板の一面と対向する状態で前記第１基板に接合される第２基板と、を備え、前記第１基板と前記第２基板の窪み部との間の空間を含んで気密室が構成され、前記気密室が真空とされた半導体装置の製造方法は、シリコンを含有する前記第１基板を用意することと、前記第２基板の前記一面に前記窪み部が形成され、シリコンを含有する前記第２基板を用意することと、前記気密室が構成されるように、前記第１基板の一面と前記第２基板の一面とを接合することと、前記気密室内の水素ガスを排出するための加熱処理することと、前記第１基板の一面と前記第２基板の一面とを接合することの前に、前記第１基板の一面側および前記第２基板の窪み部の壁面を含む一面側にＯＨ基を生成することを備える。前記第１基板の一面と前記第２基板の一面とを接合することでは、前記第１基板の一面に生成されたＯＨ基と前記第２基板の一面に生成されたＯＨ基を共有結合させる。前記加熱処理することでは、１℃／ｓｅｃ以下の昇温速度で、前記第１基板および前記第２基板のうちの前記ＯＨ基が生成された部分が７００℃以上となるように加熱することによって水素ガスを発生させると共に、前記水素ガスの拡散距離が前記気密室を構成する壁面と外気に曝される壁面との間の最短距離以上となるように加熱温度および加熱時間を調整することによって前記水素ガスを前記気密室から排出する。 In an aspect of the present disclosure, a first substrate having one surface, one surface and the other surface opposite to the one surface, a recess is formed on the one surface side, and the one surface faces one surface of the first substrate. A second substrate bonded to the first substrate in a state, and a hermetic chamber is formed including a space between the first substrate and the recess of the second substrate, and the hermetic chamber is vacuumed According to the method for manufacturing a semiconductor device, the first substrate containing silicon is prepared, and the second substrate containing silicon is prepared by forming the depression on the one surface of the second substrate. Bonding one surface of the first substrate and one surface of the second substrate so that the hermetic chamber is configured, heat treatment for discharging hydrogen gas in the hermetic chamber, Bonding one surface of the first substrate and one surface of the second substrate Before comprises generating an OH group at one surface side including the wall surface of the recess of the first one side and the second substrate of the substrate. By bonding one surface of the first substrate and one surface of the second substrate, OH groups generated on the one surface of the first substrate and OH groups generated on the one surface of the second substrate are covalently bonded. In the heat treatment, by heating at a temperature rising rate of 1 ° C./sec or less so that the portion where the OH group is generated in the first substrate and the second substrate is 700 ° C. or more. By generating hydrogen gas and adjusting the heating temperature and heating time so that the diffusion distance of the hydrogen gas is equal to or greater than the shortest distance between the wall surface constituting the hermetic chamber and the wall surface exposed to the outside air Hydrogen gas is discharged from the hermetic chamber.
　上記の半導体装置の製造方法によれば、第１基板および第２基板にＯＨ基を生成し、第１基板と第２基板とを接合した後、１℃／ｓｅｃ以下の昇温速度で気密室を構成する壁面が７００℃以上となるように加熱する。これにより、気密室内に残存するＯＨ基を全て水素ガスに変換できる。そして、水素ガスの拡散距離が第２基板における窪み部の底面と当該第２基板の他面との間の距離以上となるように加熱温度および加熱時間を調整しているため、水素ガスを気密室から排出することができる。このため、気密室内の圧力を所望の圧力とすることができ、気密室内の圧力が変動することを抑制できる。 According to the above method for manufacturing a semiconductor device, an OH group is generated on the first substrate and the second substrate, the first substrate and the second substrate are joined, and then the hermetic chamber is heated at a rate of 1 ° C./sec or less. Is heated so that the wall surface constituting the temperature becomes 700 ° C. or higher. Thereby, all the OH groups remaining in the hermetic chamber can be converted into hydrogen gas. Since the heating temperature and the heating time are adjusted so that the diffusion distance of the hydrogen gas is equal to or greater than the distance between the bottom surface of the recess in the second substrate and the other surface of the second substrate, the hydrogen gas is removed. It can be discharged from a closed room. For this reason, the pressure in an airtight chamber can be made into a desired pressure, and it can suppress that the pressure in an airtight chamber fluctuates.
　また、加熱処理にて気密室内に残存するＯＨ基を全て水素ガスに変換させるため、半導体装置の使用中等において、気密室内で水素ガスが生成し、当該水素ガスによって気密室内の圧力が変動してしまうことを抑制できる。 Further, since all OH groups remaining in the hermetic chamber are converted into hydrogen gas by heat treatment, hydrogen gas is generated in the hermetic chamber during use of the semiconductor device, and the pressure in the hermetic chamber fluctuates due to the hydrogen gas. Can be suppressed.
　本開示についての上記目的およびその他の目的、特徴や利点は、添付の図面を参照しながら下記の詳細な記述により、より明確になる。その図面は、
図１は、本開示の第１実施形態における圧力センサの断面図であり、 図２（ａ）から図２（ｄ）は、図１に示す圧力センサの製造工程を示す断面図であり、 図３（ａ）から図３（ｃ）は、図２（ｄ）に続く圧力センサの製造工程を示す断面図であり、 図４は、水素ガス発生量と試料表面温度との関係を示す図であり、 図５は、加熱温度と気密室内の圧力との関係を示す図であり、 図６は、本開示の第２実施形態における圧力センサの断面図であり、 図７は、本開示の他の実施形態における圧力センサの断面図であり、 図８は、本開示の他の実施形態における圧力センサの断面図であり、 図９は、本開示の他の実施形態における圧力センサの断面図である。 The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings. The drawing
FIG. 1 is a cross-sectional view of a pressure sensor according to a first embodiment of the present disclosure. 2 (a) to 2 (d) are cross-sectional views showing the manufacturing process of the pressure sensor shown in FIG. FIG. 3A to FIG. 3C are cross-sectional views showing the manufacturing process of the pressure sensor following FIG. FIG. 4 is a diagram showing the relationship between the amount of hydrogen gas generated and the sample surface temperature. FIG. 5 is a diagram showing the relationship between the heating temperature and the pressure in the hermetic chamber, FIG. 6 is a cross-sectional view of a pressure sensor according to a second embodiment of the present disclosure. FIG. 7 is a cross-sectional view of a pressure sensor according to another embodiment of the present disclosure, FIG. 8 is a cross-sectional view of a pressure sensor according to another embodiment of the present disclosure, FIG. 9 is a cross-sectional view of a pressure sensor according to another embodiment of the present disclosure.
　（第１実施形態）
　本開示の第１実施形態について図面を参照しつつ説明する。なお、本実施形態では、本開示の半導体装置の製造方法を圧力センサの製造方法に適用した例について説明する。まず、本実施形態の製造方法によって製造される圧力センサの構成について説明する。 (First embodiment)
A first embodiment of the present disclosure will be described with reference to the drawings. In the present embodiment, an example in which the semiconductor device manufacturing method of the present disclosure is applied to a pressure sensor manufacturing method will be described. First, the structure of the pressure sensor manufactured by the manufacturing method of this embodiment is demonstrated.
　図１に示されるように、圧力センサは、一面１０ａおよび他面１０ｂを有する第１基板１０を備えている。本実施形態では、第１基板１０は、支持基板１１、絶縁膜１２、半導体層１３が順に積層されたＳＯＩ（Silicon on Insulator）基板で構成されている。そして、半導体層１３のうちの絶縁膜１２側と反対側の一面にて第１基板１０の一面１０ａが構成され、支持基板１１のうちの絶縁膜１２側と反対側の一面にて第１基板１０の他面１０ｂが構成されている。なお、本実施形態では、支持基板１１および半導体層１３はシリコン基板等で構成され、絶縁膜１２はＳｉＯ２やＳｉＮ等で構成されている。 As shown in FIG. 1, the pressure sensor includes a first substrate 10 having one surface 10a and another surface 10b. In the present embodiment, the first substrate 10 is configured by an SOI (Silicon on Insulator) substrate in which a support substrate 11, an insulating film 12, and a semiconductor layer 13 are sequentially stacked. Then, one surface 10a of the first substrate 10 is formed on one surface of the semiconductor layer 13 opposite to the insulating film 12 side, and the first substrate is formed on one surface of the support substrate 11 opposite to the insulating film 12 side. The other surface 10b of 10 is comprised. In the present embodiment, the support substrate 11 and the semiconductor layer 13 are made of a silicon substrate or the like, and the insulating film 12 is made of SiO 2 or SiN.
　また、第１基板１０には、他面１０ｂから凹部１４が形成されることでダイヤフラム部１５が構成されている。本実施形態では、凹部１４は、第１基板１０の他面１０ｂから絶縁膜１２に達するように形成されている。このため、ダイヤフラム部１５は、凹部１４の底面と第１基板１０の一面１０ａとの間に位置する絶縁膜１２および半導体層１３にて構成されている。 Moreover, the diaphragm part 15 is comprised in the 1st board | substrate 10 by forming the recessed part 14 from the other surface 10b. In the present embodiment, the recess 14 is formed so as to reach the insulating film 12 from the other surface 10 b of the first substrate 10. For this reason, the diaphragm portion 15 is configured by the insulating film 12 and the semiconductor layer 13 located between the bottom surface of the recess 14 and the one surface 10 a of the first substrate 10.
　ダイヤフラム部１５には、４個のゲージ抵抗１６（図１中では２個のみ図示）が形成されおり、各ゲージ抵抗１６はブリッジ回路を構成するように図示しない接続配線層によって適宜接続されている。本実施形態では、ゲージ抵抗１６は、不純物がイオン注入された後に熱処理されることによって構成された拡散層とされている。なお、本実施形態では、ゲージ抵抗１６を構成する不純物の表面濃度が１．０×１０－１８～１．０×１０－２１ｃｍ－３とされており、当該ゲージ抵抗１６が本開示の拡散層に相当している。また、特に図示しないが、第１基板１０には、各ゲージ抵抗１６と適宜接続されると共に、第２基板２０に形成される図示しない貫通電極を介して外部回路と接続される引き出し配線層等も形成されている。 Four gauge resistors 16 (only two are shown in FIG. 1) are formed in the diaphragm portion 15, and each gauge resistor 16 is appropriately connected by a connection wiring layer (not shown) so as to form a bridge circuit. . In the present embodiment, the gauge resistor 16 is a diffusion layer configured by heat treatment after impurities are ion-implanted. In the present embodiment, the surface concentration of impurities constituting the gauge resistor 16 is set to 1.0 × 10 −18 to 1.0 × 10 −21 cm −3, and the gauge resistor 16 is diffused according to the present disclosure. Corresponds to a layer. Although not particularly illustrated, a lead wiring layer or the like that is connected to the first substrate 10 as appropriate with each gauge resistor 16 and connected to an external circuit through a through electrode (not shown) formed on the second substrate 20. Is also formed.
　そして、このような第１基板１０の一面１０ａに第２基板２０が配置されている。本実施形態では、第２基板２０は、貼り合わせ基板２１と、当該貼り合わせ基板２１のうちの第１基板１０と対向する一面２１ａ側に形成された絶縁膜２２とを有しており、一面２０ａが絶縁膜２２のうちの貼り合わせ基板２１側と反対側の一面にて構成されている。なお、貼り合わせ基板２１はシリコン基板等で構成され、絶縁膜２２はＳｉＯ２やＳｉＮ等で構成されている。また、第２基板２０の他面２０ｂは、貼り合わせ基板２１のうちの一面２１ａと反対側の他面２１ｂにて構成されている。 The second substrate 20 is disposed on the one surface 10a of the first substrate 10 as described above. In the present embodiment, the second substrate 20 includes a bonded substrate 21 and an insulating film 22 formed on the one surface 21 a side facing the first substrate 10 of the bonded substrate 21. 20a is constituted by one surface of the insulating film 22 opposite to the bonded substrate 21 side. The bonded substrate 21 is made of a silicon substrate or the like, and the insulating film 22 is made of SiO 2 or SiN. In addition, the other surface 20 b of the second substrate 20 is configured by the other surface 21 b on the opposite side to the one surface 21 a of the bonded substrate 21.
　貼り合わせ基板２１の一面２１ａには、ゲージ抵抗１６と対向する部分に凹部２１ｃが形成され、絶縁膜２２は、凹部２１ｃの壁面上にも形成されている。そして、第２基板２０には、ゲージ抵抗１６と対向する部分に、凹部２１ｃの壁面上に形成された絶縁膜２２にて形造られる窪み部２０ｃが形成されている。特に限定されるものではないが、窪み部２０ｃは、平面形状が正八角形とされており、中心を通る対角線の長さが３５０μｍとされている。また、窪み部２０ｃは、窪み部２０ｃの底面と第２基板２０の他面２０ｂとの間の距離が１０～２００μｍとなるように構成されている。 On one surface 21a of the bonded substrate 21, a recess 21c is formed at a portion facing the gauge resistor 16, and the insulating film 22 is also formed on the wall surface of the recess 21c. In the second substrate 20, a recess 20 c formed by the insulating film 22 formed on the wall surface of the recess 21 c is formed in a portion facing the gauge resistor 16. Although not particularly limited, the recess 20c has a regular octagonal planar shape, and the length of the diagonal line passing through the center is 350 μm. The recess 20c is configured such that the distance between the bottom surface of the recess 20c and the other surface 20b of the second substrate 20 is 10 to 200 μm.
　そして、第２基板２０は、一面２０ａ（すなわち、絶縁膜２２）が第１基板１０の一面１０ａ（すなわち、半導体層１３）と接合されている。これにより、窪み部２０ｃによって第１基板１０と第２基板２０との間に気密室３０が形成され、当該気密室３０にゲージ抵抗１６が封止される。本実施形態では、ダイヤフラム部１５のうちの一面１０ａ側に気密室３０から所定の圧力が印加されるため、当該気密室３０が基準圧力室として機能する。 The second substrate 20 has one surface 20a (that is, the insulating film 22) joined to one surface 10a (that is, the semiconductor layer 13) of the first substrate 10. As a result, the hermetic chamber 30 is formed between the first substrate 10 and the second substrate 20 by the recess 20 c, and the gauge resistor 16 is sealed in the hermetic chamber 30. In the present embodiment, since a predetermined pressure is applied from the airtight chamber 30 to the one surface 10a side of the diaphragm portion 15, the airtight chamber 30 functions as a reference pressure chamber.
　なお、本実施形態では、第１基板１０と第２基板２０とは、後述するように、第１基板１０および第２基板２０のうちの接合面を活性化させて接合するいわゆる直接接合等で接合されている。また、特に図示しないが、第２基板２０には、第１基板１０と第２基板２０との積層方向に貫通して第１基板１０に形成された引き出し配線層を露出させる貫通孔が形成されており、当該貫通孔には引き出し配線層と適宜電気的に接続され、外部回路との接続を図るための貫通電極が形成されている。 In the present embodiment, the first substrate 10 and the second substrate 20 are so-called direct bonding that activates and bonds the bonding surfaces of the first substrate 10 and the second substrate 20 as will be described later. It is joined. Although not particularly illustrated, the second substrate 20 is formed with a through-hole that penetrates in the stacking direction of the first substrate 10 and the second substrate 20 and exposes the lead wiring layer formed in the first substrate 10. In the through hole, a through electrode is formed so as to be appropriately electrically connected to the lead wiring layer and to be connected to an external circuit.
　以上が本実施形態における圧力センサの構成である。次に、上記圧力センサの製造方法について図２（ａ）から図２（ｄ）を参照しつつ説明する。 The above is the configuration of the pressure sensor in the present embodiment. Next, a method for manufacturing the pressure sensor will be described with reference to FIGS. 2 (a) to 2 (d).
　まず、図２（ａ）に示されるように、支持基板１１、絶縁膜１２、半導体層１３が順に積層された第１基板１０を用意する。そして、一面１０ａに図示しないマスクを形成した後、不純物をイオン注入すると共に加熱処理して不純物を熱拡散させることによってゲージ抵抗１６、図示しない接続配線層、引き出し配線層等を適宜形成する。なお、この工程における加熱処理は、不純物が熱拡散するように、例えば、第１基板１０を８００～１１００℃に加熱処理することによって行う。 First, as shown in FIG. 2A, a first substrate 10 in which a support substrate 11, an insulating film 12, and a semiconductor layer 13 are sequentially laminated is prepared. Then, after forming a mask (not shown) on one surface 10a, an impurity is ion-implanted and heat treatment is performed to thermally diffuse the impurity, thereby appropriately forming a gauge resistor 16, a connection wiring layer (not shown), a lead-out wiring layer, and the like. Note that the heat treatment in this step is performed, for example, by heat-treating the first substrate 10 at 800 to 1100 ° C. so that impurities are thermally diffused.
　次に、上記図２（ａ）とは別工程において、図２（ｂ）に示されるように、貼り合わせ基板２１を用意し、貼り合わせ基板２１の一面２１ａにドライエッチング等で凹部２１ｃを形成する。そして、基板２１の一面２１ａに化学気相成長（すなわち、Chemical Vapor Deposition：ＣＶＤ）法等で絶縁膜２２を形成する。これにより、絶縁膜２２にて形造られる上記窪み部２０ｃが形成された第２基板２０が用意される。 Next, in a step different from that shown in FIG. 2A, a bonded substrate 21 is prepared as shown in FIG. 2B, and a recess 21c is formed on one surface 21a of the bonded substrate 21 by dry etching or the like. To do. Then, the insulating film 22 is formed on the one surface 21a of the substrate 21 by a chemical vapor deposition (ie, chemical vapor deposition (CVD)) method or the like. Thereby, the 2nd board | substrate 20 in which the said hollow part 20c formed by the insulating film 22 was formed is prepared.
　続いて、第１基板１０（半導体層１３）と第２基板２０（絶縁膜２２）とを真空中で接合する。本実施形態では、まず、図２（ｃ）に示されるように、第１基板１０の一面１０ａ側および第２基板２０の一面２０ａ側にＯＨ基を生成する。 Subsequently, the first substrate 10 (semiconductor layer 13) and the second substrate 20 (insulating film 22) are bonded in a vacuum. In this embodiment, first, as shown in FIG. 2C, OH groups are generated on the one surface 10 a side of the first substrate 10 and the one surface 20 a side of the second substrate 20.
　具体的には、第１基板１０および第２基板２０を図示しないチャンバ内に配置し、第１基板１０の一面１０ａ（すなわち、半導体層１３）側および第２基板２０の一面２０ａ（すなわち、絶縁膜２２）側からＯ２プラズマ、Ｎ２プラズマ、Ａｒイオンビーム等を照射し、接合面に付着している不純物を除去すると共に各接合面を活性化させる。 Specifically, the first substrate 10 and the second substrate 20 are disposed in a chamber (not shown), and the one surface 10a (that is, the semiconductor layer 13) side of the first substrate 10 and the one surface 20a (that is, insulating) of the second substrate 20 are disposed. Irradiation with O 2 plasma, N 2 plasma, Ar ion beam or the like is performed from the film 22) side to remove impurities adhering to the bonding surface and to activate each bonding surface.
　なお、接合面を活性化させるとは、接合面に露出した原子における結合手の一部が結合相手を失った状態とすることである。また、接合面を活性化させる際には、第１基板１０の一面１０ａ側および第２基板２０の一面２０ａ側からＯ２プラズマ等を照射するため、第１基板１０の一面１０ａにおける第２基板２０と接合される領域よりも内縁側の領域、および第２基板２０の窪み部２０ｃの壁面等も活性化される。 The activation of the bonding surface means that a part of the bond in the atom exposed on the bonding surface has lost the bonding partner. Further, when the bonding surface is activated, O 2 plasma or the like is irradiated from the one surface 10a side of the first substrate 10 and the one surface 20a side of the second substrate 20, so that the second substrate on the one surface 10a of the first substrate 10 is activated. The region on the inner edge side of the region bonded to 20, the wall surface of the recess 20 c of the second substrate 20, and the like are also activated.
　次に、例えば、第１基板１０および第２基板２０をチャンバ内から取り出して大気に曝すことにより、第１基板１０の一面１０ａ側および第２基板２０の一面２０ａ側にＯＨ基を生成する。 Next, for example, by removing the first substrate 10 and the second substrate 20 from the chamber and exposing them to the atmosphere, OH groups are generated on the one surface 10 a side of the first substrate 10 and the one surface 20 a side of the second substrate 20.
　なお、ＯＨ基は、第１基板１０および第２基板２０の活性化された領域に生成されるため、第１基板１０の一面１０ａにおける第２基板２０と接合される領域よりも内縁側の領域、および第２基板２０の窪み部２０ｃの壁面等にも形成される。また、第１基板１０および第２基板２０の各一面１０ａ、２０ａ側にＯＨ基を生成する際には、第１基板１０および第２基板２０をチャンバ内から取り出す代わりに、例えば、チャンバ内に大気を導入することで第１基板１０および第２基板２０にＯＨ基を生成するようにしてもよい。 Since the OH group is generated in the activated region of the first substrate 10 and the second substrate 20, the region closer to the inner edge than the region bonded to the second substrate 20 on the one surface 10 a of the first substrate 10. , And on the wall surface of the recess 20c of the second substrate 20 and the like. Further, when generating OH groups on the surfaces 10a and 20a of the first substrate 10 and the second substrate 20, instead of taking out the first substrate 10 and the second substrate 20 from the chamber, for example, in the chamber OH groups may be generated on the first substrate 10 and the second substrate 20 by introducing the atmosphere.
　次に、図２（ｄ）に示されるように、第１基板１０および第２基板２０に適宜設けられたアライメントマーク等を用いて赤外顕微鏡等によるアライメントを行い、室温～５５０℃の低温で接合するいわゆる直接接合により、第１基板１０と第２基板２０とを接合する。本実施形態では、３００℃に維持しつつ、第１基板１０と第２基板２０との積層方向に１８ｋＮの加重を印加して第１基板１０と第２基板２０とを直接接合する。これにより、第１基板１０と第２基板２０の窪み部２０ｃとの間の空間を含んで気密室３０が構成され、当該気密室３０にゲージ抵抗１６が封止される。 Next, as shown in FIG. 2 (d), alignment is performed by an infrared microscope or the like using alignment marks or the like appropriately provided on the first substrate 10 and the second substrate 20, and at a low temperature of room temperature to 550 ° C. The first substrate 10 and the second substrate 20 are bonded by so-called direct bonding. In the present embodiment, the first substrate 10 and the second substrate 20 are directly bonded by applying a weight of 18 kN in the stacking direction of the first substrate 10 and the second substrate 20 while maintaining the temperature at 300 ° C. As a result, the hermetic chamber 30 is formed including the space between the first substrate 10 and the recessed portion 20 c of the second substrate 20, and the gauge resistor 16 is sealed in the hermetic chamber 30.
　なお、この工程では、以下の反応式［Ｆ１］のように、第１基板１０の一面１０ａおよび第２基板２０の一面２０ａに生成されたＯＨ基同士が共有結合することによって水素ガス３１が発生する。 In this step, as shown in the following reaction formula [F1], hydrogen gas 31 is generated by the covalent bonding of OH groups generated on one surface 10a of the first substrate 10 and one surface 20a of the second substrate 20. To do.
　２ＳｉＯＨ→ＳｉＯＳｉ＋Ｈ２＋Ｏ－…［Ｆ１］
　つまり、図２（ｄ）の工程が終了した後には、気密室３０内に水素ガス３１が発生した状態となり、気密室３０内の圧力が所望の圧力より高くなった状態となっている。 2SiOH → SiOSi + H 2 + O − ... [F1]
That is, after the process of FIG. 2D is completed, hydrogen gas 31 is generated in the hermetic chamber 30, and the pressure in the hermetic chamber 30 is higher than a desired pressure.
　続いて、図３（ａ）に示されるように、図２（ｄ）の工程まで行ったものを図示しないアニール装置に導入して加熱処理する。これにより、第１基板１０と第２基板２０との接合に寄与しなかったＯＨ基、つまり第１基板１０の一面１０ａにおける第２基板２０と接合される領域よりも内縁側の領域に生成されたＯＨ基、および第２基板２０の窪み部２０ｃの壁面に生成されたＯＨ基同士が結合し、水分子が生成される。 Subsequently, as shown in FIG. 3A, the process up to the process of FIG. 2D is introduced into an annealing apparatus (not shown) and heat-treated. As a result, the OH group that has not contributed to the bonding between the first substrate 10 and the second substrate 20, that is, the region on the inner edge side of the region bonded to the second substrate 20 on the one surface 10 a of the first substrate 10 is generated. The OH groups and the OH groups generated on the wall surface of the recess 20c of the second substrate 20 are bonded to each other to generate water molecules.
　その後、図３（ｂ）に示されるように、加熱を続けることにより、以下の反応式［Ｆ２］のように、水分子とシリコンが反応し、酸化膜が生成される（すなわち、厚くなる）と共に更なる水素ガス３１が気密室３０内に発生する。 Thereafter, as shown in FIG. 3B, by continuing heating, water molecules react with silicon as shown in the following reaction formula [F2], and an oxide film is generated (that is, thickened). At the same time, further hydrogen gas 31 is generated in the hermetic chamber 30.
　２Ｈ２Ｏ＋Ｓｉ→ＳｉＯ２＋２Ｈ２…［Ｆ２］
　ここで、本発明者らは、Ｓｉ基板にＯＨ基を生成し、Ｓｉ基板を加熱した際にＯＨ基に起因する水素ガス３１の発生量について実験を行い、図４に示す実験結果を得た。なお、図４は、Ｏ２プラズマを照射することによってＯＨ基を生成した後に昇温脱離ガス分光（すなわち、Thermal DesorptionSpectrometry：ＴＤＳ）法を行うことによって得られた実験結果であり、昇温速度を１℃／ｓｅｃとしている。また、図４中の試料表面温度はＯＨ基が生成されている表面温度のことであり、図４中の破線で示すバックグラウンドは実験に使用した装置固有のノイズである。 2H 2 O + Si → SiO 2 + 2H 2 ... [F2]
Here, the inventors generated an OH group on the Si substrate and conducted an experiment on the generation amount of the hydrogen gas 31 caused by the OH group when the Si substrate was heated, and obtained the experimental result shown in FIG. . FIG. 4 shows experimental results obtained by performing a thermal desorption spectroscopy (TDS) method after generating OH groups by irradiating O 2 plasma, and the rate of temperature increase. Is 1 ° C./sec. The sample surface temperature in FIG. 4 is the surface temperature at which OH groups are generated, and the background indicated by the broken line in FIG. 4 is noise specific to the apparatus used in the experiment.
　図４に示されるように、Ｓｉ基板にＯＨ基を生成した場合、加熱して試料表面温度を高くすることで水素ガスが発生するが、本発明者らは、昇温速度を１℃／ｓｅｃとした場合には７００℃以上で水素ガスが発生しなくなることを見出した。また、明確な原理については明らかではないが、昇温速度を１℃／ｓｅｃより小さくした場合には水素ガス発生量の最大量における温度が低温側にずれ、昇温速度を１℃／ｓｅｃより大きくした場合には、水素ガス発生量の最大量における温度が高温側にずれることが知られている。つまり、昇温速度を１℃／ｓｅｃより小さくした場合には水素ガスが発生しなくなる温度が低温側にずれ、昇温速度を１℃／ｓｅｃより大きくした場合には、水素ガスが発生しなくなる温度が高温側にずれることが知られている。さらに、図４に示されるように、本発明者らは、プラズマ湿度を変更した場合には、水素ガス発生量の最大量、および最大量における温度が変動するが、水素ガスが発生しなくなる温度は変化しないことも見出した。 As shown in FIG. 4, when OH groups are generated on the Si substrate, hydrogen gas is generated by heating to raise the sample surface temperature. In this case, it was found that hydrogen gas is not generated at 700 ° C. or higher. Further, although the clear principle is not clear, when the rate of temperature rise is less than 1 ° C./sec, the temperature at the maximum amount of hydrogen gas generation shifts to the low temperature side, and the rate of temperature rise is less than 1 ° C./sec. When it is increased, it is known that the temperature at the maximum amount of hydrogen gas generation shifts to the high temperature side. That is, the temperature at which hydrogen gas is not generated shifts to a low temperature side when the temperature rising rate is lower than 1 ° C./sec, and hydrogen gas is not generated when the temperature rising rate is higher than 1 ° C./sec. It is known that the temperature shifts to the high temperature side. Further, as shown in FIG. 4, when the plasma humidity is changed, the present inventors change the maximum amount of hydrogen gas generated and the temperature at the maximum amount, but the temperature at which hydrogen gas is not generated. Also found no change.
　このため、本実施形態では、昇温速度を１℃／ｓｅｃ以下とし、ＯＨ基が生成された面が７００℃以上となるように加熱するようにしている。つまり、第１基板１０の一面１０ａ、第２基板２０の一面２０ａ、および窪み部２０ｃの壁面が７００℃以上となるように加熱している。これにより、図２（ｃ）の工程にて生成したＯＨ基を全て水素ガス３１に変換できる。 For this reason, in this embodiment, the heating rate is set to 1 ° C./sec or less, and heating is performed so that the surface on which the OH group is generated is 700 ° C. or more. That is, the heating is performed so that the one surface 10a of the first substrate 10, the one surface 20a of the second substrate 20, and the wall surface of the recess 20c are 700 ° C. or higher. Thereby, all the OH groups generated in the step of FIG.
　なお、図３（ｂ）は、図２（ｃ）の工程にてＯＨ基が生成された面が７００℃以上となる前の状態を示している。また、図２（ｄ）の工程では、第１基板１０および第２基板２０の各接合面に生成されたＯＨ基同士は、上記反応式［Ｆ１］のように反応するが、ＯＨ基の一部が残存する場合がある。このため、図３（ｂ）の工程にて、第１基板１０および第２基板２０の接合面も７００℃以上となるように加熱することにより、図２（ｄ）の工程にて反応しなかったＯＨ基が存在する場合には、当該ＯＨ基を水素ガス３１に変換できる。 In addition, FIG.3 (b) has shown the state before the surface in which the OH group was produced | generated in the process of FIG.2 (c) became 700 degreeC or more. In the step of FIG. 2D, OH groups generated on the bonding surfaces of the first substrate 10 and the second substrate 20 react as shown in the above reaction formula [F1]. May remain. For this reason, in the process of FIG. 3B, the bonding surface of the first substrate 10 and the second substrate 20 is heated so as to be 700 ° C. or higher, so that no reaction occurs in the process of FIG. In the case where an OH group is present, the OH group can be converted into hydrogen gas 31.
　その後、図３（ｃ）に示されるように、加熱温度（すなわち、７００℃以上の温度）を維持し、気密室３０内に発生した水素ガス３１を当該気密室３０内から外部に排出するガス抜き工程を行う。 Thereafter, as shown in FIG. 3C, a gas that maintains the heating temperature (that is, a temperature of 700 ° C. or higher) and discharges the hydrogen gas 31 generated in the hermetic chamber 30 from the hermetic chamber 30 to the outside. A blanking process is performed.
　ここで、ガス抜き工程について具体的に説明する。水素ガス３１の拡散距離は、周知のように、拡散係数（Ｄ）と加熱時間（ｔ）に比例し（すなわち、２（Ｄｔ）１／２）、拡散係数（Ｄ）は、加熱温度に比例する。つまり、水素ガス３１の拡散距離は、加熱時間と加熱温度に比例する。 Here, the degassing step will be specifically described. As is well known, the diffusion distance of the hydrogen gas 31 is proportional to the diffusion coefficient (D) and the heating time (t) (that is, 2 (Dt) 1/2 ), and the diffusion coefficient (D) is proportional to the heating temperature. To do. That is, the diffusion distance of the hydrogen gas 31 is proportional to the heating time and the heating temperature.
　そして、本発明者らは、水素ガス３１が気密室３０を構成する壁面と外気に曝される壁面との間の最短距離となる部分を拡散（すなわち、通過）して排出されるように、当該最短距離以上の距離を水素ガス３１の拡散距離とし、当該拡散距離が一定となるように加熱温度と加熱時間を調整して実験を行い、図５に示される実験結果を得た。なお、本実施形態では、気密室３０を構成する壁面と外気に曝される壁面との最短距離となる部分は、窪み部２０ｃの底面と第２基板２０の他面２０ｂとの間の部分となる。また、図５は、気密室３０内の体積を１．０×１０－３ｍｍ－３とし、窪み部２０ｃの底面と第２基板２０の他面２０ｂとの間の距離を１０～２００μｍとし、昇温速度を１℃／ｓｅｃとした際の図である。 Then, the inventors diffuse (i.e., pass through) the portion that becomes the shortest distance between the wall surface that forms the hermetic chamber 30 and the wall surface that is exposed to the outside air, and discharge the hydrogen gas 31. Experiments were conducted by adjusting the heating temperature and the heating time so that the diffusion distance of the hydrogen gas 31 was a distance equal to or longer than the shortest distance and the diffusion distance was constant, and the experimental results shown in FIG. 5 were obtained. In the present embodiment, the shortest distance between the wall surface constituting the hermetic chamber 30 and the wall surface exposed to the outside air is the portion between the bottom surface of the recess 20c and the other surface 20b of the second substrate 20. Become. 5 shows that the volume in the hermetic chamber 30 is 1.0 × 10 −3 mm −3 and the distance between the bottom surface of the recess 20c and the other surface 20b of the second substrate 20 is 10 to 200 μm. It is a figure at the time of temperature rising rate being 1 degree-C / sec.
　図５に示されるように、窪み部２０ｃの底面と第２基板２０の他面２０ｂとの間の距離以上の距離を拡散距離とし、拡散距離はＤ１／２、ｔ１／２に比例するために当該拡散距離が一定となるように加熱温度（すなわち、拡散係数）と加熱時間とを調整した場合であっても、例えば、加熱温度が６００℃では、気密室３０内の圧力を十分に減圧することができないことが判った。つまり、加熱温度が６００℃では、気密室３０内の水素ガス３１を十分に排出することができないことが判った。なお、上記のように、Ｄは拡散係数であり、ｔは加熱時間である。 As shown in FIG. 5, a distance equal to or greater than the distance between the bottom surface of the recess 20c and the other surface 20b of the second substrate 20 is defined as a diffusion distance, and the diffusion distance is proportional to D 1/2 and t 1/2 . Therefore, even when the heating temperature (that is, the diffusion coefficient) and the heating time are adjusted so that the diffusion distance is constant, for example, when the heating temperature is 600 ° C., the pressure in the hermetic chamber 30 is sufficiently increased. It was found that the pressure could not be reduced. That is, it was found that when the heating temperature is 600 ° C., the hydrogen gas 31 in the hermetic chamber 30 cannot be sufficiently discharged. As described above, D is a diffusion coefficient, and t is a heating time.
　これは、上記のように、６００℃では、ＯＨ基が全て水素ガス３１に変換されず、６００℃に維持することによって少量ずつ水素ガス３１の発生が継続しているためであると推察される。なお、図５では、加熱温度を６００℃とした際には、加熱時間を７５時間という長時間とすることにより、水素ガス３１の拡散距離を窪み部２０ｃの底面と第２基板２０の他面２０ｂとの間の距離以上としている。 This is presumably because, as described above, at 600 ° C., all the OH groups are not converted to the hydrogen gas 31, and by maintaining the temperature at 600 ° C., the generation of the hydrogen gas 31 is continued little by little. . In FIG. 5, when the heating temperature is 600 ° C., the diffusion time of the hydrogen gas 31 is set to the bottom surface of the recess 20 c and the other surface of the second substrate 20 by setting the heating time to a long time of 75 hours. It is set as more than the distance between 20b.
　これに対し、ＯＨ基が生成されている面が７００℃以上となるように加熱した場合には、図４に示されるように、図２（ｃ）で生成したＯＨ基を全て水素ガス３１に変換できる。このため、ガス抜き工程では、拡散距離が窪み部２０ｃの底面と第２基板２０の他面２０ｂとの間の距離以上となるように、加熱温度および加熱時間を調整することにより、気密室３０内に発生した水素ガス３１を気密室３０から排出することができ、気密室３０内の圧力を所望の圧力にすることができる。 On the other hand, when the surface on which OH groups are generated is heated to 700 ° C. or higher, as shown in FIG. 4, all the OH groups generated in FIG. Can be converted. For this reason, in the degassing step, the hermetic chamber 30 is adjusted by adjusting the heating temperature and the heating time so that the diffusion distance is equal to or greater than the distance between the bottom surface of the recess 20c and the other surface 20b of the second substrate 20. The hydrogen gas 31 generated inside can be discharged from the hermetic chamber 30, and the pressure in the hermetic chamber 30 can be set to a desired pressure.
　なお、本実施形態では、上記のように、気密室３０を構成する壁面と外気に曝される壁面との最短距離となる部分は、窪み部２０ｃの底面と第２基板２０の他面２０ｂとの間の部分となる。このため、図３（ｃ）では、窪み部２０ｃの底面と第２基板２０の他面２０ｂとの間の部分を通過して水素ガス３１が排出される様子を示している。しかしながら、例えば、気密室３０を構成する壁面と外気に曝される壁面との最短距離となる部分が第１基板１０の一面１０ａと他面１０ｂとの間の部分となる場合には、水素ガス３１は、第１基板１０の一面１０ａと他面１０ｂとの間の部分を拡散して排出される。 In the present embodiment, as described above, the shortest distance between the wall surface configuring the airtight chamber 30 and the wall surface exposed to the outside air is the bottom surface of the recess 20c and the other surface 20b of the second substrate 20. The part between. For this reason, FIG. 3C shows a state in which the hydrogen gas 31 is discharged through a portion between the bottom surface of the recess 20c and the other surface 20b of the second substrate 20. However, for example, when the shortest distance between the wall surface constituting the hermetic chamber 30 and the wall surface exposed to the outside air is a portion between the one surface 10a and the other surface 10b of the first substrate 10, hydrogen gas 31 is discharged by diffusing a portion between one surface 10a and the other surface 10b of the first substrate 10.
　また、Ｓｉの融点は１４１２℃であるため、加熱工程は１４１２℃未満で行うことが好ましい。そして、上記では、図３（ｂ）ではＯＨ基が生成されている面が７００℃以上となるように加熱し、図３（ｃ）ではそのままの温度を維持する例について説明したが、図３（ｃ）のガス抜き工程では、水素ガス３１の拡散距離が加熱温度と加熱時間に比例する。このため、例えば、図３（ｂ）の工程でＯＨ基が生成されている面が７００℃以上となるように加熱した後、図３（ｃ）の工程では６００℃まで降温し、加熱時間を長くすることにより、拡散距離が窪み部２０ｃの底面と第２基板２０の他面２０ｂとの間の距離以上となるようにしてもよい。 Further, since the melting point of Si is 1412 ° C., the heating step is preferably performed at less than 1412 ° C. In the above description, an example in which the surface on which the OH group is generated is heated to 700 ° C. or higher in FIG. 3B and the temperature is maintained in FIG. In the degassing step (c), the diffusion distance of the hydrogen gas 31 is proportional to the heating temperature and the heating time. For this reason, for example, after heating the surface on which OH groups are generated in the step of FIG. 3B to be 700 ° C. or higher, the temperature is lowered to 600 ° C. in the step of FIG. By increasing the length, the diffusion distance may be greater than or equal to the distance between the bottom surface of the recess 20c and the other surface 20b of the second substrate 20.
　その後は特に図示しないが、第１基板１０の他面１０ｂにマスクを形成し、ドライエッチング等で凹部１４を形成してダイヤフラム部１５を構成することにより、上記図１に示す圧力センサが製造される。 Thereafter, although not shown in particular, the pressure sensor shown in FIG. 1 is manufactured by forming a mask on the other surface 10b of the first substrate 10 and forming the concave portion 14 by dry etching or the like to form the diaphragm portion 15. The
　なお、上記では、１つの圧力センサの製造方法について説明したが、ウェハ状の第１基板１０と第２基板２０とを用意し、ウェハ状のまま上記各工程を行った後にこのものをダイシングカットしてチップ単位に分割するようにしてもよい。 In addition, although the manufacturing method of one pressure sensor was demonstrated above, after preparing the wafer-like 1st board | substrate 10 and the 2nd board | substrate 20, performing said each process with a wafer form, this thing is dicing cut. Then, it may be divided into chips.
　以上説明したように、本実施形態では、第１基板１０の一面１０ａ側および第２基板２０の一面２０ａ側にＯＨ基を生成し、第１基板１０と第２基板２０とを接合している。そして、昇温速度を１℃／ｓｅｃ以下とし、ＯＨ基が生成されている面が７００℃以上となるように加熱している。これにより、第１基板１０と第２基板２０とを接合するために生成したＯＨ基を完全に水素ガス３１に変換できる（図４参照）。 As described above, in the present embodiment, OH groups are generated on the one surface 10a side of the first substrate 10 and the one surface 20a side of the second substrate 20, and the first substrate 10 and the second substrate 20 are bonded. . And it heats so that the temperature increase rate shall be 1 degrees C / sec or less, and the surface in which the OH group is produced | generated will be 700 degrees C or more. Thereby, the OH group produced | generated in order to join the 1st board | substrate 10 and the 2nd board | substrate 20 can be completely converted into the hydrogen gas 31 (refer FIG. 4).
　そして、ガス抜き工程では、水素ガス３１の拡散距離が窪み部２０ｃの底面と第２基板２０の他面２０ｂとの間の距離以上となるように、加熱温度および加熱時間を調整している。これにより、気密室３０内の水素ガス３１を十分に排出することができ、気密室３０内を十分に減圧した状態（すなわち、真空状態）とできる。つまり、気密室３０内の圧力が変動することを抑制できる。 In the degassing step, the heating temperature and the heating time are adjusted so that the diffusion distance of the hydrogen gas 31 is equal to or greater than the distance between the bottom surface of the recess 20c and the other surface 20b of the second substrate 20. Thereby, the hydrogen gas 31 in the hermetic chamber 30 can be sufficiently discharged, and the inside of the hermetic chamber 30 can be sufficiently decompressed (that is, a vacuum state). That is, it can suppress that the pressure in the airtight chamber 30 fluctuates.
　また、加熱処理にて気密室３０内に残存するＯＨ基を全て水素ガスに変換させるため、半導体装置の使用中等において、気密室３０内で水素ガスが生成し、当該水素ガスによって気密室３０内の圧力が変動してしまうことを抑制できる。 Further, since all the OH groups remaining in the hermetic chamber 30 by the heat treatment are converted into hydrogen gas, hydrogen gas is generated in the hermetic chamber 30 during use of the semiconductor device and the like, and the hydrogen gas generates the hydrogen gas in the hermetic chamber 30. It can suppress that the pressure of fluctuates.
　（第２実施形態）
　本開示の第２実施形態について説明する。本実施形態は、第１実施形態に対して第１基板１０の構成を変更したものであり、その他に関しては第１実施形態と同様であるため、ここでは説明を省略する。 (Second Embodiment)
A second embodiment of the present disclosure will be described. In the present embodiment, the configuration of the first substrate 10 is changed with respect to the first embodiment, and the other aspects are the same as those in the first embodiment, and thus the description thereof is omitted here.
　本実施形態の圧力センサは、図６に示されるように、第１基板１０は、半導体層１３上に薄絶縁膜１７を有する構成とされている。つまり、第１基板１０は、支持基板１１、絶縁膜１２、半導体層１３、薄絶縁膜１７が順に積層されて構成され、一面１０ａが薄絶縁膜１７のうちの半導体層１３側と反対側の一面にて構成されている。また、ダイヤフラム部１５は、凹部１４の底面と第１基板１０の一面１０ａとの間に位置する絶縁膜１２、半導体層１３、薄絶縁膜１７にて構成される。 In the pressure sensor of the present embodiment, as shown in FIG. 6, the first substrate 10 is configured to have a thin insulating film 17 on the semiconductor layer 13. That is, the first substrate 10 is configured by laminating the support substrate 11, the insulating film 12, the semiconductor layer 13, and the thin insulating film 17 in this order, and one surface 10 a of the thin insulating film 17 on the side opposite to the semiconductor layer 13 side. It consists of one side. The diaphragm portion 15 includes an insulating film 12, a semiconductor layer 13, and a thin insulating film 17 positioned between the bottom surface of the recess 14 and the one surface 10 a of the first substrate 10.
　このような圧力センサは、次のように製造される。すなわち、まず、上記図２（ａ）の工程において、ゲージ抵抗１６等を形成した後、例えば、熱酸化することによって半導体層１３上に薄絶縁膜１７を形成して第１基板１０を構成する。その後、上記図２（ｂ）以降の工程を行い、図３（ａ）以降の加熱工程を行う際には、半導体層１３上に薄絶縁膜１７が形成された状態で加熱処理することにより、上記圧力センサが製造される。 Such a pressure sensor is manufactured as follows. That is, first, in the process of FIG. 2A, after forming the gauge resistor 16 and the like, the first substrate 10 is configured by forming the thin insulating film 17 on the semiconductor layer 13 by, for example, thermal oxidation. . Thereafter, the steps after FIG. 2B are performed, and when the heating step after FIG. 3A is performed, the heat treatment is performed in a state where the thin insulating film 17 is formed on the semiconductor layer 13, The pressure sensor is manufactured.
　これによれば、半導体層１３上に薄絶縁膜１７が形成された状態でガス抜き工程を行っている。このため、ガス抜き工程の際、薄絶縁膜１７によってゲージ抵抗１６を構成する不純物が気密室３０内に拡散する外方拡散（アウトディフュージョン）を抑制でき、ゲージ抵抗１６の特性が変化することを抑制できる。 According to this, the degassing process is performed with the thin insulating film 17 formed on the semiconductor layer 13. For this reason, in the degassing step, the thin insulating film 17 can suppress the outward diffusion (out diffusion) in which the impurities constituting the gauge resistor 16 diffuse into the hermetic chamber 30, and the characteristics of the gauge resistor 16 change. Can be suppressed.
　なお、上記図２（ｃ）の工程で説明した直接接合によって薄絶縁膜１７と絶縁膜２２とを接合する場合、薄絶縁膜１７が厚いと接合強度が低くなることがある。このため、薄絶縁膜１７を約１０ｎｍ以下となるように形成することが好ましい。 When the thin insulating film 17 and the insulating film 22 are bonded by the direct bonding described in the process of FIG. 2C, the bonding strength may be lowered if the thin insulating film 17 is thick. For this reason, it is preferable to form the thin insulating film 17 to be about 10 nm or less.
　（他の実施形態）
　例えば、上記第１、第２実施形態では、本開示の半導体装置の製造方法を圧力センサの製造方法に適用した例について説明した。しかしながら、本開示は、気密室３０を有し、当該気密室３０の圧力が真空状態である種々の半導体装置の製造方法に適用することができ、角速度センサ等の製造方法にも適用することができる。 (Other embodiments)
For example, in the first and second embodiments, the example in which the semiconductor device manufacturing method of the present disclosure is applied to the pressure sensor manufacturing method has been described. However, the present disclosure can be applied to manufacturing methods of various semiconductor devices that include the hermetic chamber 30 and the pressure of the hermetic chamber 30 is in a vacuum state, and can also be applied to manufacturing methods of angular velocity sensors and the like. it can.
　また、図７に示されるように、第２基板２０を貼り合わせ基板２１のみで構成した圧力センサの製造方法に本開示を適用するようにしてもよい。なお、この圧力センサでは、第２基板２０の窪み部２０ｃが貼り合わせ基板２１の凹部２１ｃにて構成され、窪み部２０ｃの底面と第２基板２０の他面２０ｂとの間に位置する部分は貼り合わせ基板２１のみとなる。また、図１において、特に図示しないが、凹部２１ｃの壁面に絶縁膜２２が形成されていない構成としてもよい。 Further, as shown in FIG. 7, the present disclosure may be applied to a method for manufacturing a pressure sensor in which the second substrate 20 includes only the bonded substrate 21. In this pressure sensor, the recessed portion 20c of the second substrate 20 is configured by the recessed portion 21c of the bonded substrate 21, and the portion located between the bottom surface of the recessed portion 20c and the other surface 20b of the second substrate 20 is Only the bonded substrate 21 is provided. Further, although not particularly shown in FIG. 1, the insulating film 22 may not be formed on the wall surface of the recess 21c.
　そして、図８に示されるように、第１基板１０を支持基板１１のみで構成すると共に、窪み部２０ｃの底面と第２基板２０の他面２０ｂとの間に位置する貼り合わせ基板２１および絶縁膜２２をダイヤフラム部１５とし、このダイヤフラム部１５にゲージ抵抗１６を形成した圧力センサの製造方法に本開示を適用するようにしてもよい。さらに、図９に示されるように、図８の変形例として、第１基板１０を支持基板１１および絶縁膜１２で構成し、第２基板２０を貼り合わせ基板２１のみで構成した圧力センサの製造方法に本開示を適用するようにしてもよい。なお、この圧力センサでは、図７に示される圧力センサと同様に、第２基板２０の窪み部２０ｃが貼り合わせ基板２１の凹部２１ｃで構成され、窪み部２０ｃの底面と第２基板２０の他面２０ｂとの間に位置する部分は貼り合わせ基板２１のみとなる。 Then, as shown in FIG. 8, the first substrate 10 is composed only of the support substrate 11, and the bonded substrate 21 and the insulation positioned between the bottom surface of the recess 20 c and the other surface 20 b of the second substrate 20. The present disclosure may be applied to a method of manufacturing a pressure sensor in which the membrane 22 is the diaphragm portion 15 and the gauge resistor 16 is formed on the diaphragm portion 15. Further, as shown in FIG. 9, as a modification of FIG. 8, the manufacturing of the pressure sensor in which the first substrate 10 is configured by the support substrate 11 and the insulating film 12, and the second substrate 20 is configured only by the bonded substrate 21. The present disclosure may be applied to a method. In this pressure sensor, similarly to the pressure sensor shown in FIG. 7, the recessed portion 20 c of the second substrate 20 is configured by the recessed portion 21 c of the bonded substrate 21, and the bottom surface of the recessed portion 20 c and the second substrate 20 The portion located between the surface 20 b is only the bonded substrate 21.
　また、上記第１実施形態において、ダイヤフラム部１５は、半導体層１３のみで構成されていてもよい。つまり、凹部１４によって絶縁膜１２が除去されていてもよい。同様に、上記第２実施形態において、ダイヤフラム部１５は、半導体層１３および薄絶縁膜１７にて構成されていてもよい。 Further, in the first embodiment, the diaphragm portion 15 may be composed of only the semiconductor layer 13. That is, the insulating film 12 may be removed by the recess 14. Similarly, in the second embodiment, the diaphragm portion 15 may be composed of the semiconductor layer 13 and the thin insulating film 17.
　本開示は、実施例に準拠して記述されたが、本開示は当該実施例や構造に限定されるものではないと理解される。本開示は、様々な変形例や均等範囲内の変形をも包含する。加えて、様々な組み合わせや形態、さらには、それらに一要素のみ、それ以上、あるいはそれ以下、を含む他の組み合わせや形態をも、本開示の範疇や思想範囲に入るものである。 Although the present disclosure has been described based on the embodiments, it is understood that the present disclosure is not limited to the embodiments and structures. The present disclosure includes various modifications and modifications within the equivalent range. In addition, various combinations and forms, as well as other combinations and forms including only one element, more or less, are within the scope and spirit of the present disclosure.

Claims (2)

  1. 　一面（１０ａ）を有する第１基板（１０）と、
    　一面（２０ａ）および前記一面と反対側の他面（２０ｂ）を有し、前記一面側に窪み部（２０ｃ）が形成され、当該一面が前記第１基板の一面と対向する状態で前記第１基板に接合される第２基板（２０）と、を備え、
    　前記第１基板と前記第２基板の窪み部との間の空間を含んで気密室（３０）が構成され、前記気密室が真空とされた半導体装置の製造方法において、
    　シリコンを含有する前記第１基板を用意することと、
    　前記第２基板の前記一面に前記窪み部が形成され、シリコンを含有する前記第２基板を用意することと、
    　前記気密室が構成されるように、前記第１基板の一面と前記第２基板の一面とを接合することと、
    　前記気密室内の水素ガス（３１）を排出するための加熱処理することと、
    　前記第１基板の一面と前記第２基板の一面とを接合することの前に、前記第１基板の一面側および前記第２基板の窪み部の壁面を含む一面側にＯＨ基を生成することを備え、
    　前記第１基板の一面と前記第２基板の一面とを接合することでは、前記第１基板の一面に生成されたＯＨ基と前記第２基板の一面に生成されたＯＨ基を共有結合させ、
    　前記加熱処理することでは、１℃／ｓｅｃ以下の昇温速度で、前記第１基板および前記第２基板のうちの前記ＯＨ基が生成された部分が７００℃以上となるように加熱することによって水素ガスを発生させると共に、前記水素ガスの拡散距離が前記気密室を構成する壁面と外気に曝される壁面との間の最短距離以上となるように加熱温度および加熱時間を調整することによって前記水素ガスを前記気密室から排出する半導体装置の製造方法。     A first substrate (10) having one surface (10a);
    The first surface in a state of having one surface (20a) and the other surface (20b) opposite to the one surface, the recess portion (20c) being formed on the one surface side, and the one surface facing one surface of the first substrate. A second substrate (20) bonded to the substrate,
    In the method of manufacturing a semiconductor device, wherein a hermetic chamber (30) is configured including a space between the first substrate and the recess of the second substrate, and the hermetic chamber is evacuated.
    Providing the first substrate containing silicon;
    Providing the second substrate having the depression formed on the one surface of the second substrate and containing silicon;
    Bonding one surface of the first substrate and one surface of the second substrate so that the hermetic chamber is configured;
    Heat treatment for discharging hydrogen gas (31) in the hermetic chamber;
    Before bonding one surface of the first substrate and one surface of the second substrate, generating OH groups on one surface side including the one surface side of the first substrate and the wall surface of the recessed portion of the second substrate. With
    By bonding one surface of the first substrate and one surface of the second substrate, an OH group generated on the one surface of the first substrate and an OH group generated on the one surface of the second substrate are covalently bonded,
    In the heat treatment, by heating at a temperature rising rate of 1 ° C./sec or less so that the portion where the OH group is generated in the first substrate and the second substrate is 700 ° C. or more. By generating hydrogen gas and adjusting the heating temperature and heating time so that the diffusion distance of the hydrogen gas is equal to or greater than the shortest distance between the wall surface constituting the hermetic chamber and the wall surface exposed to the outside air A method for manufacturing a semiconductor device, wherein hydrogen gas is discharged from the hermetic chamber.
  2. 　前記第１基板と前記第２基板とを接合することの前に、前記第１基板の一面側に不純物を拡散させることによって拡散層（１６）を形成することと、前記拡散層を覆うと共に前記第１基板の一面を構成する薄絶縁膜（１７）を形成することとをさらに備え、
    　前記第２基板を用意することでは、前記第１基板と前記第２基板とを接合することの際に前記拡散層と対向する部分に前記窪み部が形成されたものを用意し、
    　前記加熱処理することでは、前記第１基板に前記薄絶縁膜が形成された状態で前記加熱処理する請求項１に記載の半導体装置の製造方法。     Before bonding the first substrate and the second substrate, forming a diffusion layer (16) by diffusing impurities on one surface side of the first substrate, covering the diffusion layer and Forming a thin insulating film (17) constituting one surface of the first substrate,
    In preparing the second substrate, prepare the one in which the hollow portion is formed in a portion facing the diffusion layer when the first substrate and the second substrate are bonded,
    The method for manufacturing a semiconductor device according to claim 1, wherein the heat treatment is performed in a state where the thin insulating film is formed on the first substrate.
PCT/JP2016/000553 2015-02-16 2016-02-03 Semiconductor device production method WO2016132694A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN201680006742.2A CN107209078B (en) 2015-02-16 2016-02-03 The manufacturing method of semiconductor device
US15/528,124 US9944515B2 (en) 2015-02-16 2016-02-03 Manufacturing method of semiconductor device

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2015027738 2015-02-16
JP2015-027738 2015-02-16
JP2015242400A JP6341190B2 (en) 2015-02-16 2015-12-11 Manufacturing method of semiconductor device
JP2015-242400 2015-12-11

Publications (1)

Publication Number Publication Date
WO2016132694A1 true WO2016132694A1 (en) 2016-08-25

Family

ID=56692255

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2016/000553 WO2016132694A1 (en) 2015-02-16 2016-02-03 Semiconductor device production method

Country Status (1)

Country Link
WO (1) WO2016132694A1 (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07104217B2 (en) * 1988-05-27 1995-11-13 横河電機株式会社 Vibration transducer and manufacturing method thereof
JP4161432B2 (en) * 1998-10-28 2008-10-08 株式会社デンソー Semiconductor pressure sensor and manufacturing method thereof

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07104217B2 (en) * 1988-05-27 1995-11-13 横河電機株式会社 Vibration transducer and manufacturing method thereof
JP4161432B2 (en) * 1998-10-28 2008-10-08 株式会社デンソー Semiconductor pressure sensor and manufacturing method thereof

Similar Documents

Publication Publication Date Title
JP6341190B2 (en) Manufacturing method of semiconductor device
JP5783297B2 (en) Mechanical quantity sensor
KR101044503B1 (en) Method of producing a plate-shaped structure, in particular, from silicon, use of said method and plate-shaped structure thus produced, in particular from silicon
KR20090042712A (en) Soi substrates with a fine buried insulating layer
JP2008294417A5 (en)
JP2009135468A5 (en) Method for manufacturing semiconductor substrate and semiconductor device
US10054609B2 (en) Semiconductor device and method for manufacturing same
US9029960B2 (en) Semiconductor device and method of manufacturing the same
JP5776232B2 (en) Manufacturing method of electronic device
JP6174756B2 (en) Manufacturing method of SOI substrate
WO2016132694A1 (en) Semiconductor device production method
JP2009076784A5 (en)
JP2009039843A (en) Electric part and its manufacturing method
JP6221965B2 (en) Semiconductor device and manufacturing method thereof
US11027968B2 (en) Semiconductor device with discharge path, and method for producing the same
US10622246B2 (en) Substrate bonding method
WO2016143282A1 (en) Substrate bonding method
JP5884667B2 (en) Manufacturing method of semiconductor device
JP6273322B2 (en) Manufacturing method of SOI substrate
JP5999027B2 (en) Physical quantity sensor
JP2018069395A (en) MEMS device
JP2017028178A (en) Three-dimensional mounting method for semiconductor wafer and joining method for semiconductor wafer
JP5454485B2 (en) Manufacturing method of bonded substrate
JP2022049603A (en) Method for manufacturing semiconductor device
JP2016131198A (en) Semiconductor device and semiconductor device manufacturing method

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 16752085

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 15528124

Country of ref document: US

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 16752085

Country of ref document: EP

Kind code of ref document: A1