JP4671900B2 - Joining method and joining apparatus - Google Patents

Description

  The present invention relates to a bonding method and apparatus for bonding bonding surfaces of substrates, and a bonded substrate manufactured by the method and apparatus.

  Conventionally, as a method for protecting semiconductor elements, surface acoustic wave elements, and other various electronic elements from the influence of moisture, oxygen, etc. existing in the atmosphere, the electronic elements are accommodated inside the container and the interior of the container is sealed. Thus, a technique for sealing an electronic element is known.

  For electronic devices in which such electronic elements are placed and sealed in the internal space, various technologies have been proposed to improve the air tightness (sealing property) inside the container and prevent moisture and other substances from entering more reliably. Has been. For example, conventionally, an opening of a ceramic substrate having a cavity (concave portion) having an electronic element mounted on the bottom surface is covered with a metal lid, and the ceramic substrate and the metal lid are joined and sealed using solder, glass powder, or the like. To be done.

  On the other hand, a technique of sealing an electronic element by sealing a gap between the electronic element mounted by flip chip bonding and the substrate is also used. For example, in Patent Document 1, in the manufacture of a surface acoustic wave device, a package substrate to which a surface acoustic wave chip is flip-chip connected is sealed with a low-melting glass, thereby sealing with a resin. A technique for obtaining higher airtightness is described.

  By the way, as described in Patent Document 1, when sealing with a low melting point glass or joining members constituting a container with solder or glass powder, high airtightness can be obtained. Heat treatment for melting low melting glass or solder at a high temperature is required, and it is not suitable for sealing an electronic element having low heat resistance. In particular, electronic devices such as compound semiconductors have low heat resistance, and thus are highly likely to be damaged by high-temperature heating.

  There is also a method in which an electronic element is directly formed on a silicon substrate and sealed by using a glass lid and heating at 400 ° C. to join the silicon substrate and the glass lid by anodic bonding. In this case, the substrates are directly sealed and separated into individual pieces by a dicing method. However, due to the high temperature in anodic bonding, parts with low heat resistance may be thermally damaged.

As a processing method for lowering the temperature and bonding, Patent Document 2 describes a method of bonding after hydrophilic treatment.
JP 2003-110402 A JP-A-2005-294800

  However, in the bonding method described in Patent Document 2, since bonding is performed under heating in a vacuum, there is a high possibility that bonding is performed without being heated uniformly on the front surface of the substrate. Inferior, resulting in a decrease in the yield of the final product. Moreover, since it heat-joins in a vacuum, there exists a subject that productivity falls.

  The present invention has been made in view of the above problems, and a bonding method and a bonding apparatus that can bond substrates to be bonded at a low temperature in a sealed space state with high productivity and high reliability, and An object is to provide a bonded substrate manufactured by the method and apparatus.

In order to achieve the above object, the invention according to claim 1 is a bonding method for bonding the bonding surfaces of the substrates to each other, wherein the bonding surface of one substrate and the bonding surface of the other substrate are made of water or water vapor. A cleaning process for cleaning by irradiating energy waves in the atmosphere, a process for gradually reducing the power for irradiating energy waves, setting the power to zero and stopping the irradiation of the energy waves, And a bonding step of bonding the cleaned bonding surfaces of the one substrate and the other substrate while applying pressure after the irradiation is stopped .

  According to a second aspect of the present invention, in the bonding method according to the first aspect, the cleaning step is performed in a reduced pressure atmosphere having a pressure lower than the atmospheric pressure.

  The invention described in claim 3 is characterized in that, in the bonding method according to claim 1 or 2, cleaning is performed in an atmosphere having a pressure of 120 Pa to 300 Pa in the cleaning step.

According to a fourth aspect of the present invention, in the joining method according to any one of the first to third aspects, an energy wave is generated in an atmosphere of argon gas, oxygen gas, or a mixed gas of argon gas and oxygen gas before the cleaning step. It is characterized by washing | cleaning by.

According to a fifth aspect of the present invention, in the bonding method according to the first aspect, after the bonding step, there is a heating step of heating both the bonded substrates in atmospheric pressure.

The invention described in claim 6 is characterized in that, in the bonding method according to claim 1 or 4 , any one of plasma discharge, ion beam, atom beam, and radical beam is used as the energy wave.

The invention according to claim 7 is characterized in that, in the bonding method according to claim 1, the bonding surfaces of the respective substrates are bonded in a state where a hydroxyl group is interposed.

The invention according to claim 8 is a bonding apparatus for bonding the bonding surfaces of the substrates, and the energy wave is applied to the bonding surface of one substrate and the bonding surface of the other substrate in an atmosphere of water or water vapor. A cleaning means for cleaning by irradiating, a controller for gradually decreasing the power for irradiating the energy wave after the cleaning is completed, and setting the power to zero to stop the irradiation of the energy wave; After stopping, a bonding means for bonding the cleaned bonding surfaces of the one substrate and the other substrate while applying pressure is provided.

The invention according to claim 9, in the bonding apparatus according to claim 8, the control unit is further an atmosphere in the wash, and wherein the Turkey set atmosphere is a 120Pa~300Pa pressure.

Invention according to claim 1 0, in the joining apparatus according to claim 8 or 9 wherein, prior to washing, means for cleaning the energy wave in an argon gas or oxygen gas or argon gas and in an atmosphere of a mixed gas of oxygen gas It is provided with.

The invention of claim 1 1, in the bonding apparatus according to claim 8 or 10, wherein the energy waves, plasma, ion beam, atomic beam, characterized in that either a radical beam.

  According to the present invention, the bonding surfaces of opposing substrates to be bonded can be bonded at a low temperature by cleaning them by irradiating energy waves such as plasma in an atmosphere using water. At that time, the processing effect of the low temperature bonding can be improved by performing plasma processing with an inert gas in advance, or by gradually reducing the power when the plasma processing is stopped. Furthermore, reliability is improved by heating in the atmosphere after bonding. By doing in this way, it becomes possible to bond a board | substrate highly reliably and firmly at low temperature.

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

  FIG. 1 is a cross-sectional view showing a configuration of an electronic device package which is an embodiment of a bonded substrate according to the present invention.

  In FIG. 1, an electronic device package 1 includes a substrate 12 as a bonding target on which a plurality of semiconductor devices 11 as electronic devices are formed, and a plurality of cavities (concaves) for housing the semiconductor devices 11. And the lid member 13 as the other substrate to be joined having the portion 14.

  The lid member 13 is provided with a groove part 15 for dicing the chip after the cavity part 14 and finally the substrate 12 and the lid member 13 are joined. The substrate 12 and the lid member 13 are made of Si (silicon).

  An electric circuit (not shown) for receiving and transmitting electric signals from the semiconductor element 11 is formed on the substrate 12 and is electrically connected to the outside through a through hole 16 in which copper 18 is embedded. . Reference numeral 17 denotes an electrode for mounting an individual chip after dicing to an external substrate.

  FIG. 2 is a flowchart showing a manufacturing process of the electronic element package having the above-described configuration. The electronic element package 1 is formed by bonding a substrate 12 and a lid member 13.

  In FIG. 2, first, the formation process of the substrate 12 will be described. A plurality of semiconductor elements 11 are formed on a Si substrate which is a base material of the substrate 12 (S1). Next, the through hole 16 is formed in the Si substrate by dry etching (S2). Next, copper 18 is plated into the through hole 16 (S3), and finally, an electrode 17 is formed through a sputtering method, resist coating, exposure, development, and etching steps (S4).

  Next, the manufacturing process of the lid member 13 will be described. A cavity portion 14 is formed by dry etching processing on the Si substrate which is the base material of the lid member 13 through resist coating, exposure and development processes (S5).

  The substrate 12 and the lid member 13 manufactured as described above are subjected to a modification process to be described later before joining, so that the substrate 12 and the lid member 13 are joined.

  Next, Embodiment 1 of the joining method and apparatus according to the present invention will be described with reference to FIG. FIG. 3 is a cross-sectional view showing a schematic configuration of a reforming / bonding apparatus which is Embodiment 1 of the bonding apparatus according to the present invention.

  In FIG. 3, the reaction chamber 20 has a gas introduction port 21 and a vacuum exhaust port 22 and is grounded. The substrate 12 having the configuration shown in FIG. 1 is placed on the high-frequency electrode 23, and power from the high-frequency oscillator 24 is supplied to the high-frequency electrode 23 through a matching tuner and a high-frequency power supply unit (not shown). The high frequency electrode 23 is insulated from the reaction chamber 20 by an insulating ring 25. The high-frequency electrode 23, the insulating ring 25, and the reaction chamber 20 are kept in vacuum by an O-ring (not shown). Reference numeral 26 denotes a cooling groove for flowing cooling water so that the O-ring is not heated to 150 ° C. or higher.

  An upper high-frequency electrode 27 is embedded with an electrostatic chuck 28 that holds the lid member 13 configured as shown in FIG. 1 so as not to fall. The electrostatic chuck 28 is a jig that applies a voltage to the electrostatic chuck 28 and fixes the lid member 13 with a Coulomb force. The upper high-frequency electrode 27 is disposed at a position facing the high-frequency electrode 23, and power from the high-frequency oscillator 29 is supplied to the upper high-frequency electrode 27 through a matching tuner and a high-frequency power supply unit (not shown).

  The upper high-frequency electrode 27 is fixed to the bellows member 30 and can move up and down. The upper high-frequency electrode 27 is insulated from the reaction chamber 20 by the insulating ring 31. The upper high-frequency electrode 27, the insulating ring 31, and the reaction chamber 20 are kept in a vacuum by an O-ring (not shown). An O-ring (not shown) is also interposed between the bellows member 30 and the insulating ring 31 to maintain a vacuum in the reaction chamber 20. Reference numeral 32 denotes a cooling groove for flowing cooling water so that the O-ring is not heated to 150 ° C. or higher.

  A noise filter (not shown) is incorporated between the electrostatic chuck 28 and the power supply wiring so that the high frequency power from the high frequency transmitter 29 is not input to the power supply (not shown) of the electrostatic chuck 28. .

  An earth electrode 33 is fixed to the earth electrode bellows member 34 and is movable by the earth electrode bellows member 34.

  The high-frequency electrode 23 and the upper high-frequency electrode 27 form the main part of the cleaning means and the joining means in the first embodiment.

  The manufacturing process of the electronic element package in the reforming / bonding apparatus of Embodiment 1 configured as described above will be described below.

  A high frequency of 200 W is applied to the high-frequency electrode 23 and the upper high-frequency electrode 27 while keeping the degree of vacuum in the reaction chamber 20 at 20 Pa while flowing water vapor (water is also acceptable) from the gas inlet 21. Plasma discharge occurs between the high-frequency electrode 23 and the ground electrode 33, and between the upper high-frequency electrode 27 and the ground electrode 33, and oxygen ions, hydrogen ions, oxygen radicals, hydrogen radicals, and electrons are generated.

  The plasma treatment is performed on the substrate 12 and the lid member 13 for 30 seconds. The junction surface between the substrate 12 and the lid member 13 exposed to the plasma is irradiated with oxygen ions or hydrogen ions in the plasma, and the junction surface between the substrate 12 and the lid member 13 is sputtered by the ion irradiation. As a result, contaminants are removed, resulting in a clean surface (cleaning process).

  In addition, hydroxyl groups (—OH) are formed on the bonding surfaces of the substrate 12 and the lid member 13 by oxygen radicals or hydrogen radicals.

  After the plasma processing, the high frequency power from the high frequency transmitters 24 and 29 is stopped, and the supply of water vapor from the gas inlet 21 is stopped.

Next, the ground electrode bellows member 34 is extended to move the ground electrode 33 outward, and the bellows 30 is compressed to move the upper high-frequency electrode 27 downward, so that the lid member 13 on the upper high-frequency electrode 27 is moved. And the substrate 12 on the high-frequency electrode 23 are brought into contact with each other and pressurized and bonded with a pressure of 5 × 10 ⁵ N / m ² (bonding step).

  As described above, according to the first embodiment, the surface (bonding surface) of the substrate 12 and the lid member 13 is cleaned by performing the plasma treatment in which water vapor is supplied to the substrate 12 and the lid member 13, and the hydroxyl group Therefore, bonding at room temperature becomes possible.

As a result, the electronic device package 1 manufactured at room temperature was diced and divided into chips, and as a result, good bonding could be obtained. As a result of measuring the shear strength of the electronic device package 1, it was 3.4 × 10 ⁷ N / m ² . Moreover, when it joined without pressurizing with the pressure of 5 * 10 < ⁵ > N / m < ² >, the result of the dispersion | variation in intensity | strength was large depending on the curvature state of the board | substrate.

  Next, Embodiment 2 of the joining method and apparatus according to the present invention will be described with reference to FIG. FIG. 4 is a cross-sectional view showing a schematic configuration of a reforming / bonding apparatus which is Embodiment 2 of the bonding apparatus according to the present invention.

  In FIG. 4, reference numeral 40 denotes a reaction chamber. The substrate 12 having the configuration shown in FIG. 1 is placed on the substrate base 41, and the lid member 13 is fixed to the upper substrate base 42. An electrostatic chuck 43 is embedded in the upper substrate base 42, and the lid member 13 is attracted to the electrostatic chuck 43 by applying a voltage to the electrostatic chuck 43. The upper substrate base 42 is attached to the bellows member 44. By moving the bellows member 44 up and down, the upper substrate base 42 can move up and down. 45 is a vacuum exhaust port.

  46 is a neutral beam source for the substrate for modifying the substrate 12, and 47 is a neutral beam source for the lid member for modifying the lid member 13. Both neutral beam sources 46, 47 are connected to gas supply pipes 48, 49 and power supply wirings 50, 51, respectively. The gas supply pipes 48 and 49 and the power supply wirings 50 and 51 are maintained at a vacuum degree by the supply connectors 52 and 53.

  The neutral beam source for substrate 46 and the neutral beam source for lid member 47 constitute the main part of the cleaning means in the second embodiment, and the substrate base 41 and the upper substrate base 42 in the second embodiment. It forms the main part of the joining means.

  The manufacturing process of the electronic device package in the reforming / bonding apparatus of Embodiment 2 configured as described above will be described below.

After the reaction chamber 40 is evacuated to a vacuum degree of 10 ⁻⁵ Pa, 20 sccm of water vapor is supplied to the gas supply pipes 48 and 49 to the neutral beam sources 46 and 47, respectively, and a voltage of 1.2 KV is supplied from the power supply wirings 50 and 51. Apply. Since the reaction chamber 40 is supplied with water vapor, the degree of vacuum is maintained at 10 ⁻² Pa. Plasma is generated in the neutral beam sources 46 and 47, and oxygen radicals and hydrogen radicals are extracted from the neutral beam sources 46 and 47, respectively.

  The substrate 12 is irradiated with oxygen radicals and hydrogen radicals from the substrate neutral beam source 46, and the lid member 13 is irradiated with oxygen radicals and hydrogen radicals from the lid member neutral beam source 47. The bonding surfaces of the substrate 12 and the lid member 13 are cleaned by a sputtering action, and hydroxyl groups (—OH) are formed by hydrogen radicals or oxygen radicals (cleaning step).

After irradiating oxygen radicals and hydrogen radicals for 60 seconds, the upper substrate base 42 to which the lid member 13 is fixed is lowered, the lid member 13 is brought into contact with the substrate 12 and applied at a pressure of 5 × 10 ⁵ N / m ^2. Press to join (joining process).

As a result of measuring the shear strength of the bonded substrate which is the electronic device package 1 manufactured as described above, it was 3.5 × 10 ⁷ N / m ² .

  As described above, according to the second embodiment, by treating the substrate 12 and the lid member 13 with the neutral beam sources 46 and 47 to which water vapor is supplied, the bonding surfaces of the substrate 12 and the lid member 13 are Since it is cleaned by sputtering and a hydroxyl group is formed, bonding at room temperature is possible. As a result of dicing the electronic package 1 formed at room temperature and dividing it into chips, it was possible to obtain good bonding.

  Next, Embodiment 3 of the joining method and apparatus according to the present invention will be described with reference to FIG. In the following description, the members already described in FIG. 3 are denoted by the same reference numerals, the description thereof will be omitted, and the manufacturing process of the electronic element package in the reforming / bonding apparatus of Embodiment 3 will be described.

  While flowing argon gas from the gas inlet 21 at 10 sccm, a high frequency of 200 W is applied to the high-frequency electrode 23 and the upper high-frequency electrode 27 while maintaining the degree of vacuum in the reaction chamber 20 at 20 Pa. Thereby, plasma discharge is generated between the high-frequency electrode 23 and the ground electrode 33 and between the upper high-frequency electrode 27 and the ground electrode 33 to generate argon ions. This plasma treatment is performed on the substrate 12 and the lid member 13 for 30 seconds. Argon ions in the plasma are irradiated onto the bonding surface of the substrate 12 and the lid member 13 exposed to the plasma, and the bonding surface of the substrate 12 and the lid member 13 is contaminated by sputtering due to the irradiation of ions. It is removed and becomes a clean surface (pre-cleaning step).

  Next, a high frequency of 200 W is applied to the high-frequency electrode 23 and the upper high-frequency electrode 27 while maintaining the degree of vacuum in the reaction chamber 20 at 20 Pa while flowing water at 20 sccm from the gas inlet 21. As a result, plasma discharge occurs between the high-frequency electrode 23 and the ground electrode 33 and between the upper high-frequency electrode 27 and the ground electrode 33 to generate oxygen ions, hydrogen ions, oxygen radicals, hydrogen radicals, and electrons. This plasma treatment is performed on the substrate 12 and the lid member 13 for 30 seconds. The bonding surface between the substrate 12 and the lid member 13 exposed to the plasma is irradiated with oxygen ions or hydrogen ions present in the plasma, and the bonding surface between the substrate 12 and the lid member 13 is caused by the sputtering effect by irradiation of the ions. Removes contaminants to a clean surface (cleaning step).

  In addition, hydroxyl groups (—OH) are formed on the bonding surfaces of the substrate 12 and the lid member 13 by oxygen radicals or hydrogen radicals.

After the plasma processing, the high frequency power from the high frequency transmitters 24 and 29 is stopped, and the supply of water vapor from the gas inlet 21 is stopped. Next, the ground electrode bellows member 34 is extended to move the ground electrode 33 outward, and the bellows member 30 is compressed to move the upper high-frequency electrode 27 downward, and the lid member on the upper high-frequency electrode 27 13 and the substrate 12 on the high-frequency electrode 23 are brought into contact with each other and pressurized and bonded with a pressure of 5 × 10 ⁵ N / m ² (bonding step).

  As described above, according to the third embodiment, the substrate 12 and the lid member 13 are first supplied with argon gas, subjected to plasma treatment with argon ions, and then subjected to the first cleaning, and then supplied with water vapor. By performing the plasma treatment and performing the second cleaning, the bonding surfaces of the substrate 12 and the lid member 13 are cleaned well and hydroxyl groups are formed, so that bonding at room temperature is possible. The electronic package 1 thus formed at room temperature was diced and divided into chips. As a result, good bonding could be obtained.

In particular, compared with the electronic package of Embodiment 1, the effect of cleaning the substrate with argon ions was large, and a better result was obtained. As a result of measuring the shear strength, it was 4.2 × 10 ⁷ N / m ² . In the case of dicing and dividing into chips, in Embodiment 3, the chip defect rate of Embodiment 1 (in a state where the substrate and the lid member were peeled off) was improved by 1.2%. This is probably because the sputtering rate of argon is higher than that of hydrogen ions or oxygen ions, so that a better cleaning effect can be obtained before forming a hydroxyl group.

  Next, Embodiment 4 of the joining method and apparatus according to the present invention will be described with reference to FIG. In the following description, the members already described in FIG. 3 are denoted by the same reference numerals, the description thereof is omitted, and the manufacturing process of the electronic element package in the reforming / bonding apparatus of Embodiment 4 will be described.

  A high frequency of 200 W is applied to the high-frequency electrode 23 and the upper high-frequency electrode 27 in a state where the degree of vacuum in the reaction chamber 20 is maintained at 20 Pa while flowing water vapor at 20 sccm from the gas inlet 21. As a result, plasma discharge is generated between the high-frequency electrode 23 and the ground electrode 33 and between the upper high-frequency electrode 27 and the ground electrode to generate oxygen ions, hydrogen ions, oxygen radicals, hydrogen radicals, and electrons. This plasma treatment is performed on the substrate 12 and the lid member 13 for 30 seconds. The bonding surface between the substrate 12 and the lid member 13 exposed to the plasma is irradiated with oxygen ions or hydrogen ions in the plasma, and the bonding surface between the substrate 12 and the lid member 13 is caused by a sputtering action by the irradiation of ions. Contaminants are removed, resulting in a clean surface (cleaning process).

  In addition, hydroxyl groups (—OH) are formed on the bonding surfaces of the substrate 12 and the lid member 13 by oxygen radicals or hydrogen radicals.

  In the fourth embodiment, after the plasma treatment for 30 seconds, the high-frequency power from the high-frequency transmitters 24 and 29 is gradually increased over 10 seconds after 30 seconds as shown in FIG. 5 without changing the power from 200 W to 0 W. Reduce voltage. And after stopping the high frequency electric power from the high frequency transmitters 24 and 29, supply of the water vapor | steam from the gas inlet 21 is stopped.

Next, the ground electrode bellows member 34 is extended, the ground electrode 33 is moved outward, the bellows member 30 is compressed, the upper high-frequency electrode 27 is moved downward, and the lid member on the upper high-frequency electrode 27 13 and the substrate 12 on the high-frequency electrode 23 are brought into contact with each other and pressurized and bonded with a pressure of 5 × 10 ⁵ N / m ² (bonding step).

  As described above, according to the fourth embodiment, the bonding surface of the substrate 12 and the lid member 13 is cleaned and a hydroxyl group is formed by the plasma processing in which water vapor is supplied to the substrate 12 and the lid member 13. Further, by gradually reducing the high-frequency power, the concentration of the hydroxyl group on the surface can be improved as compared with the first embodiment without causing the hydroxyl group to be sputtered again by plasma, and the bonding at room temperature becomes stronger. .

As a result of dicing the electronic package 1 formed at room temperature according to the fourth embodiment and dividing it into chips, good bonding could be obtained. As a result of measuring the shear strength, it was 3.7 × 10 ⁷ N / m ² .

  Next, Embodiment 5 of the joining method according to the present invention will be described.

The reforming / bonding apparatus in the fifth embodiment is the same as the apparatus shown in FIG. 3 used in the first embodiment. In the same apparatus, when the bonding strength was measured by changing the pressure of the degree of vacuum in the reaction chamber 20, as shown in FIG. 6, the bonding strength was 3 in the case of a pressure of 20 Pa (in the case of Embodiment 1). Whereas it is 4 × 10 ⁷ N / m ^2, it is 4.1 × 10 ⁷ N / m ^{2 at} 150 Pa, and 4.2 × 10 ⁷ N / m ^{2 at} 200 Pa. The higher the pressure, the higher the bonding strength. The trend was high. However, at 350 Pa, abnormal discharge occurred without stable discharge.

  Therefore, it was found that the pressure of 120 Pa to 300 Pa is good in the bonding strength. This is presumably because when the pressure is 20 Pa, there is much irradiation with ions, but in the region where the pressure is 100 Pa or higher, radicals are increased more than ions and more hydroxyl groups are bonded.

  As described above, according to the fifth embodiment, by setting the pressure at the time of bonding to 120 to 300 Pa, it is possible to realize a reliable bonding with higher bonding strength.

  Next, the joining method in Embodiment 6 of this invention is demonstrated.

  In the reforming / bonding apparatus according to Embodiment 6 of the present invention, the electronic device package 1 is annealed in the atmosphere after being processed under the same conditions as those of the apparatus shown in FIG. When the change in bonding strength when heated for 3 hours and measured for 3 hours was measured, as shown in FIG. Referring to FIG. 3, the annealing temperature must be determined in consideration of the heat resistance of the semiconductor element 11, the substrate 12, and the lid member 13, but it has been found that the higher the temperature, the higher the reliability. did.

  As described above, according to the sixth embodiment, after the substrate 12 and the lid member 13 are bonded by cleaning (modifying), the bonding strength is increased by heating at a temperature of 100 ° C. or higher in the atmosphere. By improving and heating in the atmosphere, uniform heating is realized and reliable bonding can be realized. Furthermore, productivity can be increased as compared with bonding involving heating in a vacuum.

  In the first to sixth embodiments, a control unit composed of a CPU (Central Processing Unit) or the like is provided for performing the method and controlling each unit.

  As mentioned above, although embodiment which concerns on this invention was described, this invention is not limited to the structure of each said embodiment, A various deformation | transformation is possible.

  For example, the plasma treatment in the argon gas atmosphere is performed before the water vapor treatment in the third embodiment. However, even if the plasma treatment is performed in the oxygen gas atmosphere instead of the argon gas, the sputtering effect and the organic substance removal effect are obtained. Therefore, there is a similar effect.

  The generation of plasma is not limited to the method using parallel plate electrodes as in the first, third, and fourth embodiments, and the modification (cleaning) method using a neutral beam as in the second embodiment. For example, it may be modified by an ion beam.

  In the fourth embodiment, after the plasma treatment for 30 seconds, the power is gradually reduced from 200 W to 0 W over 10 seconds. However, it is important to gradually reduce the power, especially in 10 seconds. It is not limited.

  Also, in the case of the second embodiment, if the treatment is performed in an argon gas atmosphere as in the third embodiment before the reforming treatment with water vapor, the bonding surface can be cleaned by the sputtering treatment effect before the hydroxyl group is formed. Therefore, a better modification effect can be obtained.

  Further, also in the second embodiment, when the reforming process is performed with water vapor, the effect of the sputtering process is reduced by gradually decreasing the power supply to the power supply wirings 50 and 51 as in the fourth embodiment. However, a hydroxyl group can be supplied, and a better modification effect can be obtained.

  Further, by embedding the electrostatic chucks 28 and 36 in the high-frequency electrode 23 according to the first and third embodiments and the substrate table 34 according to the second embodiment, the bonding can be performed with higher accuracy.

In the first to sixth embodiments, the lid member 13 is made of silicon. However, other insulating materials such as ceramic and glass (SiO ₂ ) can be used.

  In the first to sixth embodiments, the bonding process is performed in a vacuum. However, after the reforming process is performed, it is possible to return to atmospheric pressure and perform bonding at atmospheric pressure.

  The present invention is applied to a bonding method and apparatus for bonding the bonding surfaces of substrates in an electronic element package having an electronic element in a sealed internal space. For example, an electronic device such as an acceleration sensor, a pressure sensor, or a SAW filter is used. It is effective for use in device packages.

Sectional drawing which shows the structure of the electronic element package which is embodiment of the bonded substrate which concerns on this invention The flowchart which shows the manufacturing process of the electronic element package of the structure shown in FIG. Sectional drawing which shows schematic structure of the modification | reformation / joining apparatus which is Embodiment 1, 3-6 of the joining apparatus which concerns on this invention Sectional drawing which shows schematic structure of the modification | reformation / joining apparatus which is Embodiment 2 of the joining apparatus which concerns on this invention Relationship diagram between electric power and power supply time in reforming (cleaning) processing in embodiment 4 Relationship diagram between pressure and bonding strength in embodiment 5 Relationship diagram between annealing temperature and bonding strength in Embodiment 6

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electronic element package 11 Semiconductor element 12 Board | substrate 13 Lid member 20,40 Reaction chamber 21 Gas introduction port 22,45 Vacuum exhaust port 23 High frequency electrode 24,29 High frequency oscillator 27 Upper high frequency electrode 33 Ground electrode 41 Substrate base 42 Upper substrate base 46 , 47 Neutral beam source 48, 49 Gas supply piping 50, 51 Power supply wiring

Claims (11)

A bonding method for bonding the bonding surfaces of the substrates,
A cleaning step of cleaning the bonding surface of one substrate and the bonding surface of the other substrate by irradiating energy waves in an atmosphere of water or water vapor;
Gradually reducing the power for irradiating the energy wave, setting the power to zero and stopping the energy wave irradiation; and
And a bonding step of bonding the cleaned bonding surfaces of the one substrate and the other substrate while applying pressure after stopping the irradiation of the energy wave.   The bonding method according to claim 1, wherein the cleaning step is performed in a reduced-pressure atmosphere having a pressure lower than atmospheric pressure.   The bonding method according to claim 1, wherein, in the cleaning step, cleaning is performed in an atmosphere having a pressure of 120 Pa to 300 Pa.   The bonding method according to claim 1, wherein cleaning is performed by the energy wave in an atmosphere of argon gas, oxygen gas, or a mixed gas of argon gas and oxygen gas before the cleaning step.   The bonding method according to claim 1, further comprising a heating step of heating the bonded substrates in an atmospheric pressure after the bonding step.   The bonding method according to claim 1 or 4, wherein any one of plasma, ion beam, atomic beam, and radical beam is used as the energy wave.   The bonding method according to claim 1, wherein the bonding surfaces of the substrates are bonded with a hydroxyl group interposed therebetween. A bonding apparatus for bonding the bonding surfaces of substrates,
Cleaning means for cleaning the bonding surface of one substrate and the bonding surface of the other substrate by irradiating energy waves in an atmosphere of water or water vapor;
After the cleaning is completed, a control unit that gradually decreases the power for irradiating the energy wave, sets the power to zero, and stops the irradiation of the energy wave;
A bonding apparatus comprising: a bonding unit configured to bond the cleaned bonding surface between the one substrate and the other substrate while applying pressure after stopping the energy wave irradiation.   The bonding apparatus according to claim 8, wherein the controller further sets an atmosphere in the cleaning to an atmosphere having a pressure of 120 Pa to 300 Pa.   10. The bonding apparatus according to claim 8, further comprising means for cleaning with the energy wave in an atmosphere of argon gas, oxygen gas, or a mixed gas of argon gas and oxygen gas before the cleaning.   11. The bonding apparatus according to claim 8, wherein the energy wave is one of plasma, ion beam, atom beam, and radical beam.

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