JP5473235B2 - MICROSTRUCTURE DEVICE AND METHOD FOR MANUFACTURING MICROSTRUCTURE DEVICE - Google Patents

Description

  The present invention relates to a microstructure device having a configuration in which a microstructure such as a surface acoustic wave (SAW) element or a microelectromechanical mechanism (MEMS) is sealed between two substrates, and a method for manufacturing the microstructure device.

  2. Description of the Related Art In recent years, an electronic component in which a very small electromechanical mechanism, a so-called MEMS (Micro Electromechanical System) is formed by applying a processing technology for forming fine wiring such as a semiconductor integrated circuit element on a main surface of a semiconductor substrate such as a silicon wafer. Has been attracting attention, and is being developed for practical use.

Such MEMS needs to be sealed from the outside in order to prevent contamination, and various materials such as resin or glass are used as the sealing material. In particular, solder and brazing materials are often used as sealing materials because they are excellent in airtightness and can be sealed in a temperature range with little influence on MEMS (for example, patents). Reference 1). And from the recent trend of lead-free, for example, SnAgCu (tin-silver-copper) -based solder has begun to be used as a sealing material.
JP 2005-251898 A

  However, SnAgCu-based solder has a relatively low eutectic point of 217 degrees, and when electronic components using this SnAgCu-based solder are mounted on another substrate, it remelts and the shape of the sealing material changes. The hermetic seal may be impaired. Further, even if airtightness is maintained during the mounting, there is a problem that the reliability of sealing deteriorates due to a change in the shape of the sealing material.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a microstructure device having a sealing material with excellent heat resistance, and a method for manufacturing the microstructure device.

The microstructure device of the present invention includes a first substrate having a microstructure provided on the surface, a second substrate having a surface facing the microstructure, and opposing surfaces of the first substrate and the second substrate. And a sealing material that surrounds and seals the microstructure, and the sealing material includes an annular metal layer provided on the opposing surfaces of the first substrate and the second substrate, and each metal. And a CuSn compound layer including a SnCuNi compound or a SnCuPd compound that connects the metal layers and is provided in a ring shape between the layers, and the metal layer provided on the second substrate is: The surface layer is a Sn metal layer.

Further, in the fine structure, preferably, an electrode electrically connected to the micro structure provided on a surface of the first substrate, provided on at least one of the surface and the inside of the second substrate, a part comprising a wiring conductor which is led out to the front surface of the second substrate, and a conductive member that electrically connects the part of the wiring conductor and electrodes, conductive member, the same material as the sealing material Become.

The first microstructure manufacturing method of the present invention includes a first substrate having a microstructure provided on a surface, a second substrate having a surface facing the microstructure, a first substrate, and a first substrate. An annular first metal surrounding the microstructure on the surface of the first substrate, wherein the opposing surfaces of the two substrates are bonded to each other, and the sealing material surrounds and seals the microstructure. a first metal layer forming step of forming a layer, on the front surface of the second substrate, a second metal layer forming step of forming a second metal layer of the annular, first metal layer of the first substrate and the second substrate A first metal layer forming step and a second metal layer forming step, comprising: a disposing step of disposing the second metal layer facing each other; and a heating step of heating and bonding the first metal layer and the second metal layer. And forming a first metal layer and a second metal layer by laminating a plurality of metal layers, A Cu metal layer made of tin and a Sn metal layer made of tin are included in at least one of the first metal layer and the second metal layer, and in the heating step, at least one metal layer and the second metal constituting the first metal layer layer forms a CuSn compound layer mainly composed of Cu ₆ Sn ₅ between at least one metal layer constituting the second metal layer, the surface layer has to have a Sn metal layer, the first At least one of the metal layer and the second metal layer has a Ni metal layer made of nickel or a Pd metal layer made of palladium as a surface layer, and forms a CuSn compound layer having a SnCuNi compound or a SnCuPd compound in the heating step .

  In the first microstructure manufacturing method, preferably, each metal layer and second metal layer constituting the first metal layer are formed in the first metal layer forming step and the second metal layer forming step. Each metal layer is formed by a thin film method, plating, or a thin film method and plating, respectively. This manufacturing method of the microstructure device is referred to as “second manufacturing method of the microstructure device”.

  In the first or second microstructure device manufacturing method, preferably, in the first metal layer forming step or the second metal layer forming step, as a part of the first metal layer or the second metal layer, A laminated structure of a Cu metal layer made of copper and an Sn metal layer made of tin is formed. This method for manufacturing a microstructure device is referred to as a “third method for manufacturing a microstructure device”.

  In the method for manufacturing a microstructure device according to any one of the first to third, preferably, at least one of the first metal layer and the second metal layer is a Ni metal layer made of nickel, or an Au metal made of gold. In the heating step, the CuSn compound layer having the SnCuNi compound, the SnCuAu compound, or the SnCuPd compound is formed. This method for manufacturing a microstructure device is referred to as a “fourth microstructure device manufacturing method”.

  In the method for manufacturing the microstructure device according to any one of the first to third, preferably, the ratio of the total thickness of the SnCu metal layer to the total thickness of the CuSn metal layer is 1/2: 2 or more 2 / 3 or less. This manufacturing method of the microstructure device is referred to as “fifth microstructure device manufacturing method”.

  In the method for manufacturing a microstructure device according to any one of the first to third, preferably, the ratio of the total thickness of the Cu metal layer to the total thickness of the n metal layer is 1/3 or more and 1/2. The ratio of the total thickness of the metal layer made of nickel, gold, or palladium to the total thickness of the Sn metal layer is 1/30 or more and 1/20 or less. This manufacturing method of the microstructure device is referred to as “sixth manufacturing method of the microstructure device”.

According to a seventh method for manufacturing a microstructure device of the present invention, a first substrate having a microstructure on its surface, a second substrate having a surface facing the microstructure, a first substrate, An annular first metal that surrounds the microstructure on the surface of the first substrate is provided with a sealing material that joins the opposing surfaces of the second substrate and surrounds and seals the microstructure. A first metal layer forming step of forming a layer, a second metal layer forming step of forming an annular second metal layer on the surface of the second substrate, and a solder or brazing material on the first metal layer or the second metal layer and bonding a solid metal made of copper through a step of disposing so as to face the a solid-metal first metal layer, the first metal layer, a second metal layer, and by heating the solid metal first A heating step for joining the first metal layer and the solid metal, and a first metal layer forming step and a first step In the metal layer forming step, the first metal layer and the second metal layer are formed by laminating a plurality of metal layers, respectively, and at least one of the first metal layer and the second metal layer is an Sn metal layer made of tin. And forming a CuSn compound layer mainly composed of Cu ₆ Sn ₅ between at least one metal layer constituting the first metal layer and at least one metal layer constituting the second metal layer in the heating step. and is, second metal layer, the surface layer has to have a Sn metal layer, the first metal layer forming step or the second metal layer forming step, as a part of the first metal layer or second metal layer, A Ni metal layer made of nickel or a Pd metal layer made of palladium is formed on the surface layer, and a CuSn compound layer having a SnCuNi compound or a SnCuPd compound is formed in the heating step .

  In the seventh method for manufacturing a microstructure device, preferably, in the first metal layer forming step and the second metal layer forming step, each metal layer and the second metal layer constituting the first metal layer are formed. Each metal layer to be formed is formed by a thin film method, plating, or a thin film method and plating. This manufacturing method of the microstructure device is referred to as “eighth microstructure device manufacturing method”.

  In the seventh or eighth microstructure device manufacturing method, the first metal layer or the second metal layer is formed of nickel as part of the first metal layer or the second metal layer in the first metal layer formation step or the second metal layer formation step. A Ni metal layer, an Au metal layer made of gold, or a Pd metal layer made of palladium is formed, and a CuSn compound layer having a SnCuNi compound, a SnCuAu compound, or a SnCuPd compound is formed in the heating step. This method for manufacturing a microstructure device is referred to as a “ninth microstructure device manufacturing method”.

  In the seventh or eighth microstructure device manufacturing method, preferably, the ratio of the weight of the solid metal copper to the weight of the tin of the Sn metal layer is 1/3 or more and 1/2 or less. Features. This manufacturing method of the microstructure device is referred to as “tenth microstructure device manufacturing method”.

  In the ninth microstructure device manufacturing method, preferably, the ratio of the weight of solid metal copper to the weight of tin of the Sn metal layer is not less than 1/3 and not more than 1/2. The ratio of the weight of nickel, gold, or palladium in the Ni metal layer, Au metal layer, or Pd metal layer to the weight of tin is 1/20 or more and 1/10 or less.

  According to the microstructure device of the present invention, it is possible to realize a microstructure device having a sealing material with excellent heat resistance.

  Moreover, according to the manufacturing method of the microstructure of the present invention, a microstructure device having a sealing material with excellent heat resistance can be manufactured.

  Hereinafter, embodiments of a microstructure device of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1A is a sectional view and FIG. 1B is a plan view showing a configuration example of a microstructure device according to an embodiment of the present invention. Here, the sectional view of (a) is a sectional view taken along the dotted line AA of the plan view of (b). As shown in FIG. 1, the microstructure device 1 according to the present embodiment includes a first substrate 2 and a second substrate 3. On the surface 2a of the first substrate 2, a microstructure 4 is provided, and the surface 2a on which the microstructure 4 of the first substrate 2 is provided and the surface 3a of the second substrate 3 are arranged to face each other. . The microstructure device 1 includes a sealing material 5 that joins the surface 2a of the first substrate 2 and the surface 3a of the second substrate 3 and surrounds and seals the microstructure 4. Further, the microstructure device 1 includes an electrode 6 provided on the surface 2a of the first substrate 2 and a wiring conductor provided inside the second substrate 3 and one end thereof led out to the surface 3a of the second substrate 3. 7, a connection pad 7 a connected to one end of the wiring conductor 7 led to the surface 3 a of the second substrate 3, and a conductive member that electrically connects the electrode 6 and the wiring conductor 7 via the connection pad 7 a. 8 is provided.

  The microstructure 4 is a device formed from, for example, crystal or semiconductor. Examples of a device that particularly requires sealing include a SAW element, a crystal resonator, and a MEMS. Here, the MEMS will be described as an example. The MEMS is, for example, various sensors such as an optical switch, a display device, an acceleration sensor, a pressure sensor, an electric switch, an inductor, a capacitor, a resonator, an antenna, a micro relay, and a magnetic head for a hard disk. , Microphone, biosensor, DNA chip, microreactor, print head, etc. These MEMS are parts made by a so-called micromachining method based on a semiconductor microfabrication technique, and have a size of about 10 μm to several hundred μm per element.

  The first substrate 2 is made of a semiconductor such as silicon or gallium arsenide, and repeats film formation and etching on the surface to form a device. Moreover, when forming MEMS, the 1st board | substrate 2 is not restricted to a semiconductor, Glass substrates, such as Pyrex (trademark) glass, may be sufficient.

  The electrode 6 is formed on the first substrate 2 and is mainly produced by using a thin film forming method, for example, a method such as sputtering or chemical vapor deposition (CVD). Examples of thin films to be manufactured include titanium (Ti), tungsten (W), gold (Au), nickel (Ni), chromium (Cr), palladium (Pd), and platinum (Pt). May be. In the case of a multilayer thin film, the outermost layer is preferably a metal having good wettability with Sn such as Au.

  The second substrate 3 is a ceramic material such as an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, a silicon carbide sintered body, a silicon carbide sintered body, or a glass ceramic sintered body. It is formed by.

  If the second substrate 3 is made of, for example, an aluminum oxide sintered body, the second substrate 3 is formed by laminating and baking a green sheet formed by forming aluminum oxide and a raw material powder such as glass powder on the sheet. The The second substrate 3 is not limited to the one formed of an aluminum oxide sintered body, and it is preferable to select a suitable one according to the application, the characteristics of the microstructure 4 to be hermetically sealed, and the like.

  For example, since the second substrate 3 is bonded to the first substrate 2 through the sealing material 5, the reliability of bonding with the first substrate 2, that is, the hermeticity of sealing the microstructure 4 is increased. For this purpose, a mullite sintered body or a glass ceramics such as an aluminum oxide-borosilicate glass system in which the thermal expansion coefficient is approximated to that of the first substrate 2 by adjusting the kind and addition amount of the glass component, for example. It is preferable to form with a material having a small difference in thermal expansion coefficient from the first substrate 2 such as a bonded body.

  The wiring conductor 7 is formed of a metal material such as copper, silver, gold, palladium, tungsten, molybdenum, or manganese. As these forming means, for example, when the second substrate 3 is ceramic and the wiring conductor 7 is copper, a metal paste in which an appropriate organic binder and a solvent are added to and mixed with copper powder and glass powder is used. It is formed by printing on a green sheet to be the two substrates 3 by screen printing or the like and baking it together with the green sheet.

  In addition, a sintered glass-ceramic made by sintering glass containing a borosilicate glass system in an aluminum oxide filler can form a wiring conductor with copper or silver having a low electrical resistance, and also has a low relative dielectric constant and a delay in electrical signals. Therefore, it is preferable as a material for the second substrate 3 that handles high-frequency signals.

  The shape of the second substrate 3 is particularly limited as long as the function as a lid for sealing the microstructure 4 and the function as a base for forming a conductor pattern or the like can be secured. Not a thing.

  In addition, a recess may be formed on the upper surface of the second substrate 3 so as to accommodate the microstructure 4 inside. If a part of the microstructure 4 is accommodated in the recess, the height of the sealing material 5 for surrounding the microstructure 4 can be reduced, and the height of the microstructure device 1 can be reduced. It will be advantageous. Further, the external dimensions when the first substrate 2 and the second substrate 3 are viewed in plan are preferably, for example, a quadrangular shape with a side length of about several mm in order to reduce the size of the microstructure device 1. .

  The sealing material 5 has a frame shape, and is interposed between the first substrate 2 and the second substrate 3 so as to accommodate the microstructure 4 therein. The sealing material 5 functions as a side wall for hermetically sealing the microstructure 4 inside. In this case, since the thickness of the sealing material 5 corresponds to the thickness of the sealing space of the microstructure 4 when the upper surface of the second substrate 3 is planar, the sealing space of the microstructure 4 can be reduced with a simple structure. Can be formed.

FIG. 2 is a partially enlarged view of the sealing material 5 of the microstructure device 1 shown in FIG. As shown in FIG. 2, the sealing material 5 is an annular first substrate-side metal layer 10 made of a plurality of metal layers respectively provided on the opposing surfaces 2 a and 3 a of the first substrate 2 and the second substrate 3. And the second substrate side metal layer 11, and the first substrate side metal layer 10 and the second substrate side metal layer 11 are annularly provided along the first and second substrate side metal layers 10 and 11, 1 and a CuSn compound layer 12 mainly composed of _Cu 6 Sn ₅ that connects the substrate side metal layer 10 and the second substrate-side metal layer 11. This Cu ₆ Sn ₅ has a melting point of 400 ° C. or higher, and has an effect of improving the heat resistance of the sealing material 5.

  The first substrate-side metal layer 10 has a metal layer 10a made of Ti provided on the first substrate 2 and a metal layer 10b made of Cu laminated on the metal layer 10a. The second substrate-side metal layer 11 includes, for example, a metal layer 11a made of Cu or Ag provided on the second substrate 3 and a metal layer 11b made of Sn stacked on the metal layer 11a.

  Next, with reference to FIG. 3, the manufacturing method of the microstructure apparatus 1 is demonstrated. FIG. 3 is a diagram for explaining a manufacturing method of the microstructure device 1. Here, for simplicity of explanation, the first substrate 2, the second substrate 3, and the sealing material 5 are illustrated, and other components of the microstructure device 1 are omitted.

  First, as shown in FIG. 3A, the first metal layer 22 is formed on the first substrate 2, and the second metal layer 23 is formed on the second substrate 3. The first metal layer 22 is formed by forming a metal layer 22a made of Ti on the first substrate 2 and then laminating a metal layer made of Cu (hereinafter also referred to as “Cu metal layer”) 22b on the metal layer 22a. To form. In addition, the second metal layer 23 is formed, for example, by forming a metal layer 23a made of Cu or Ag on the second substrate 3 and then forming a metal layer made of Sn (hereinafter referred to as “Sn metal layer”) on the metal layer 23a. It is formed by laminating 22b. The first metal layer 22 and the second metal layer 23 are formed using, for example, a dry thin film forming method such as metal vapor deposition or sputtering, or a wet thin film forming method such as a plating method. Here, when the metal layer 22b made of Sn is formed, a plating method is often used, and it is particularly desirable to perform the formation by electrolytic plating. Moreover, when forming the metal layer 23b made of Cu, a method such as CVD, sputtering, metal vapor deposition, or plating can be used. In particular, when priority is given to at least one of the thickness accuracy, film uniformity, and film strength of the metal layers 22a, 22b, 23a, and 23b, the sputtering method is preferable, and when a certain thickness is required or high productivity is achieved. The plating method is desirable when priority is given.

Next, as shown in FIG. 3B, the first substrate 2 and the second substrate 3 are arranged to face each other, and the first and second substrates 2 and 3 are aligned. When the first substrate 2 or the second substrate 3 is a transparent substrate, alignment between the first substrate 2 and the second substrate 3 is performed by applying a target mark for alignment on each of the substrates 2 and 3 by a thin film or a plating method. And the target mark is optically observed at the same time. The target mark may be a thick film conductor produced by using a so-called co-firing technique when at least one of the first substrate 2 and the second substrate 3 forming the target mark is a ceramic substrate. The target mark generally has a circular shape or a cross shape, and it is desirable that the size of the target mark is approximately the same in the longest side or diameter with respect to the alignment accuracy. For example, when the alignment accuracy of 50 μm is required, the target mark is desirably about 50 μm. When both the first substrate 2 and the second substrate 3 are opaque substrates, an intermediate system in which an optical reflecting device such as a prism is inserted between the two substrates for alignment, or one substrate For example, a method of optically confirming the alignment mark of the other substrate from the through hole by providing a through hole may be used.

Next, as shown in FIG.3 (c), the 1st board | substrate 2 and the 2nd board | substrate 3 are joined by the thermocompression bonding method. At this time, the first metal layer 22 and the second metal layer 23 are heated and bonded. When the first substrate 2 and the second substrate 3 are joined, a load and a temperature are applied to the first substrate 2 and the second substrate 3, but when a CuSn compound layer is effectively generated, the load is 500 to 2000 N is preferable for a 6-inch substrate. When the bonding load is 500 N or more, it is easy to correct the warp generated in the substrates 2 and 3, and when the bonding load is 2000 N or less, it is possible to suppress problems such as wetting and spreading of the bonding material 5. Regarding the bonding temperature, it is desirable that the temperature is between 235 ° C. and 285 ° C. in order to produce a highly heat-resistant Cu ₆ Sn ₅ compound. At 235 ° C. or higher, Sn is easily melted and bonded, and at a temperature of 285 ° C. or lower, Cu ₆ Sn ₅ compound is appropriately formed, and it is possible to suppress a decrease in bonding strength due to excessive formation. In addition, when the bonding temperature is 285 ° C. or lower, layers other than the CuSn compound layer 12 containing Cu ₆ Sn ₅ as a main component are hardly formed. Thus, the 1st board | substrate 2 and the 2nd board | substrate 3 are joined by thermocompression bonding, and the sealing material 5 as shown in FIG.3 (d) is formed.

According to the microstructure device 1 according to the present embodiment, the sealing material 5 includes annular metal layers 10 and 11 provided on the opposing surfaces 2a and 3a of the first substrate 2 and the second substrate 3, respectively. A CuSn compound layer 12 mainly composed of Cu ₆ Sn ₅ is provided between the metal layers 10 and 11 in a ring shape along the metal layers 10 and 11 and connects the metal layers 10 and 11 to each other. Therefore, the microstructure device having the sealing material 5 having excellent heat resistance can be realized.

  In the manufacturing method of the microstructure device 1 according to the present embodiment, when each metal layer constituting the first metal layer 22 or the second metal layer 23 is formed by a thin film method or plating, each metal layer is uniformly formed in the plane direction. Can be formed. Thereby, the joining area of the 1st and 2nd metal layers 22 and 23 increases, and the heat resistance and the connection strength of the sealing material 5 become larger.

In addition, if the sealing material 5 finally includes the CuSn compound layer 12 mainly composed of Cu ₆ Sn ₅ , the first metal layer 22 formed on the surface 2 a of the first substrate 2 before thermocompression bonding and The second metal layer 23 formed on the surface 3a of the second substrate 3 may have other configurations. For example, as shown in FIG. 4, the first metal layer 22 may have a stacked structure of Sn metal layers 22b and 22d and a Cu metal layer 22c. In this case, the second metal layer 23 may have at least one of the Sn metal layer and the Cu metal layer, or may not have both. Further, instead of the first metal layer 22, the second metal layer 23 may have a stacked structure of an Sn metal layer and a Cu metal layer. In this case, the first metal layer 22 may have at least one of the Sn metal layer and the Cu metal layer, or may not have both. Furthermore, both the first metal layer 22 and the second metal layer 23 may have a laminated structure of an Sn metal layer and a Cu metal layer.

  In addition, when the ratio of the total thickness of the Cu metal layer to the total thickness of the Sn metal layer in the first metal layer 22 and the second metal layer 23 was ½ or more and 2/3 or less, it melted during thermocompression bonding. Since all the Sn layers react with the Cu layer and change to the SnCu compound layer 12, the heat resistance of the sealing material 5 is further improved.

  In the above description and FIG. 3, the metal layer 22 b of the first metal layer 22 and the metal layer 23 b of the second metal layer 23 react to change to the SnCu compound layer 12, and the metal layer of the first metal layer 22. 22a corresponds to the first substrate side metal layer 10, and the metal layer 23a of the second metal layer 23 corresponds to the second substrate side metal layer 11. However, the metal layer 22b and the metal layer 23b are all reacted. In some cases, part of the metal layer 22a may remain on the corresponding metal layer 22a or metal layer 23a. For example, the Sn layer and the Cu layer remain on the metal layer 22a and the SnCu compound layer 12 is formed between the Sn layer and the Cu layer. Improves. Further, even when either the Sn layer on the metal layer 22a or the Cu layer on the metal layer 23a remains, the heat resistance of the sealing material 5 is the same.

  One of the first metal layer 22 and the second metal layer 23 may have a Ni metal layer made of nickel, an Au metal layer made of gold, or a Pd metal layer made of palladium. In this case, when the first metal layer 22 and the second metal layer 23 are heated and joined, a CuSn compound layer having a SnCuNi compound, a SnCuAu compound, or a SnCuPd compound is formed. FIG. 5 is a partially enlarged view of the first metal layer 22 and the second metal layer 23 and the sealing material 5 formed when they are joined. As shown in FIG. 5, the first metal layer 22 is composed of, for example, four layers, and is composed of a metal layer 22 a made of Ti provided on the first substrate 2 and Pt or Pd laminated on the metal layer 22 a. A metal layer 22b made of Au laminated on the metal layer 22b, and a metal layer 22d made of Cu laminated on the metal layer 22c. Further, the second metal layer 23 is composed of, for example, three layers, a metal layer 23a made of Cu or Ag provided on the second substrate 3, a metal layer 23b made of Ni laminated on the metal layer 23a, And a metal layer 23c made of Sn stacked on the metal layer 23b.

  When these first metal layer 22 and second metal layer 23 are joined by heating, the outermost Cu metal layer and Sn metal layer of each metal layer 22, 23 are melted and connected, and the first substrate side metal A CuSn compound layer 12 having a SnCuNi compound is formed between the layer 10 and the second substrate side metal layer 11. The SnCuNi compound is easier to grow in a single direction than the SnCu compound, and in the microstructure device 1 according to the present embodiment, the crystal grows in the opposing direction of the first substrate 2 and the second substrate 3. This is more effective when it is desired to keep the first substrate 2 and the second substrate 3 sufficiently apart while maintaining the height of the material 5.

  Here, the ratio of the sum of the thicknesses of the Cu metal layers to the sum of the thicknesses of the Sn metal layers in the first metal layer 22 and the second metal layer 23 is not less than 1/2 and not more than 1/3. When the ratio of the sum of the thicknesses of the metal layers made of nickel to the sum is 1/30 or more and 1/20 or less, the shape of the formed SnCuNi compound becomes columnar crystals and does not grow more than necessary. While suppressing the crushing of the sealing material 5, thermocompression bonding can be performed without significantly affecting the sealing reliability.

  The CuSn compound layer 12 containing the SnCuAu compound or SnCuPd compound is selected by selecting the number of metal layers constituting the first metal layer 22 or the second metal layer 23, the material of each metal layer, and the arrangement of each layer. Can be formed. Furthermore, the desired CuSn compound layer 12 containing any one of the SnCuNi compound, SnCuAu compound, and SnCuPd compound can be produced by changing the conditions such as the number of layers, material, and arrangement method.

  If the conductive member 8 is made of the same material as the sealing material 5, the sealing of the microstructure 4 by the sealing material 5 and the electrical connection between the electrode 6 and the connection pad 7 a by the conductive member 8 are performed once. It can be performed in the process. That is, in the process of FIG. 3C, the first metal layer 22 and the second metal layer 23 can be joined, and the electrode 6 and the connection pad 7 a can be connected by the conductive member 8. Moreover, when the sealing material 5 is a conductive material, the inside of the sealed space can be electrically shielded from the outside, and the operational reliability of the microstructure 4 can be maintained.

  Next, another manufacturing method of the microstructure device 1 will be described with reference to FIG. FIG. 6 is a diagram for explaining another method for manufacturing the microstructure device 1. Here, for simplicity of explanation, the first substrate 2, the second substrate 3, and the sealing material 5 are illustrated, and other components of the microstructure device 1 are omitted.

  First, as shown in FIG. 6A, the first metal layer 32 is formed on the first substrate 2, and the second metal layer 33 is formed on the second substrate 3. The first metal layer 32 is formed by forming a metal layer 32a made of Ti on the first substrate 2 and then laminating a metal layer 32b made of Sn on the metal layer 32a. The second metal layer 33 is made of, for example, Ag or Cu. Then, a solid metal 34 (Cu column) made of Cu is bonded onto the second metal layer 33 via solder or brazing material (not shown).

Next, as shown in FIG. 6B, the first substrate 2 and the second substrate 3 are arranged to face each other, and the first and second substrates 2 and 3 are aligned.

And as shown in FIG.6 (c), the 1st board | substrate 2 and the 2nd board | substrate 3 are joined by the thermocompression bonding method. At this time, the first metal layer 32, the second metal layer 33, and the solid metal 34 are heated and joined. Then, the sealing material 5 having a CuSn compound layer 12 mainly composed of _Cu 6 Sn ₅ during as shown in FIG. 6 (d), the first substrate side metal layer 10 and the second substrate-side metal layer 11 Is formed.

  In addition, when the ratio of the weight of copper of the solid metal 33 to the weight of tin of the Sn metal layer in the first metal layer 32 and the second metal layer 33 was 1/3 or more and 1/2 or less, it melted at the time of thermocompression bonding. Since all the Su reacts with Cu in the solid metal and changes to the SnCu compound layer 12, the liquid phase in the sealing material 5 can be made completely solid, and the sealing material has excellent airtightness. 5 can be realized.

  The solid metal 34 may be bonded to the second metal layer 33 instead of the first metal layer 32.

  Further, at least one of the first metal layer 32 and the second metal layer 33 may have a Ni metal layer made of nickel, an Au metal layer made of gold, or a Pd metal layer made of palladium. In this case, when the first metal layer 32, the second metal layer 33, and the solid metal 34 are joined by heating, the CuSn compound layer 12 having the SnCuNi compound, the SnCuAu compound, or the SnCuPd compound is formed.

  FIG. 7 is a partially enlarged view of the first metal layer 32 and the second metal layer 33 in this case and the sealing material 5 formed when they are joined. As shown in FIG. 7, the first metal layer 32 is composed of, for example, four layers, and is composed of a metal layer 32a made of Ti provided on the first substrate 2 and Pt or Pd stacked on the metal layer 32a. A metal layer 32b made of Au stacked on the metal layer 32b, and a metal layer 32d made of Sn stacked on the metal layer 32c. The second metal layer 33 is composed of, for example, two layers, and includes a metal layer 33a made of Cu or Ag provided on the second substrate 3, and a metal layer 23b made of Ni stacked on the metal layer 33a. Have. A metal solid 34 is bonded onto the metal layer 23b via a solder or brazing material 35 made of, for example, silver.

  When the first metal layer 32 and the second metal layer 33 are joined by heating, the outermost Sn metal layer and the solid metal 34 of the metal layer 32 are melted and connected, and the first substrate side metal layer 10 and A CuSn compound layer 12 having a SnCuNi compound is formed between the second substrate side metal layer 11 and the second substrate side metal layer 11. The SnCuNi compound is easier to grow in a single direction than the SnCu compound, and in the microstructure device 1 according to the present embodiment, the crystal grows in the opposing direction of the first substrate 2 and the second substrate 3. This is more effective when it is desired to keep the first substrate 2 and the second substrate 3 sufficiently apart while maintaining the height of the material 5.

  The number of metal layers constituting the first metal layer 32 and the second metal layer 33, the material of each metal layer, and the manner of arrangement are not limited to those described above. For example, the first metal layer 32 is made of, for example, three layers, and a metal layer 32a made of Ti provided on the first substrate 2, a metal layer 32b made of Pt or Pd stacked on the metal layer 32a, A metal layer 32c made of Au laminated on the metal layer 32b, and a metal solid 34 made of Cu may be bonded to the metal layer 32c via, for example, solder made of Sn or brazing material 35. At this time, the second metal layer 33 is composed of three layers, a metal layer 33a made of Cu or Ag provided on the second substrate 3, and a metal layer made of Ni laminated on the metal layer 33a. 33b and a metal layer 33c made of Sn stacked on the metal layer 33b may be included.

  Further, by selecting the number of metal layers constituting the first metal layer 32 or the second metal layer 33, the material of each metal layer, and the manner of arrangement, at least one of the SnCuNi compound, the SnCuAu compound, and the SnCuPd compound is changed. The CuSn compound layer 12 containing can be formed.

  Here, the ratio of the weight of Cu of the solid metal 34 to the weight of tin of the Sn metal layer in the first metal layer 32 and the second metal layer 33 is not less than 1/3 and not more than 1/2, If the ratio of the weight of nickel, gold, or palladium to the weight is 1/20 or more and 1/10 or less, the shape of the formed SnCuNi compound, SnCuAu compound, or SnCuPd compound becomes a columnar crystal and does not grow more than necessary. Therefore, thermocompression bonding can be performed without significantly affecting the sealing reliability while suppressing the crushing of the sealing material 5 during thermocompression bonding.

  In addition, when wafer scale packaging is performed and a microstructure device is obtained in an array shape, the first substrate 2 and the second substrate 3 are bonded as shown in FIGS. 3 (d) and 6 (d). Then, a cutting (dicing) step is included. For example, when the first substrate 2 is a ceramic substrate and the second substrate 3 is a silicon substrate, since the cutting conditions are different, the ceramic substrate is first cut and the silicon substrate is cut. You may perform what is called a step cut which separates from. In this case, the cutting conditions on the ceramic side are such that the cutting blade has a grinding wheel particle size of about 400 to 800, a thickness of 0.1 to 0.2 mm, and a cutting speed of 0.5 to 4 mm / s. The cutting conditions of the blade are preferably a grinding wheel particle size # 1000 to 2000, a thickness of 0.05 to 0.1 mm, and a cutting speed of 10 to 20 mm / s. In consideration of productivity, when both substrates are cut together, an intermediate cutting blade is selected, and a good cutting section can be obtained by setting the cutting speed to 1 mm / s or less. In this way, the microstructure device 1 singulated can be obtained.

  In addition, when measuring the thickness of each metal layer, the joined body portion of an arbitrary microstructure device is vertically cross-sectional processed. Thereafter, the thickness of each layer is measured using a scanning electron microscope (SEM) or the like. When observing metal layers having no change in appearance, the thickness is specified by performing element identification and mapping using Electro Probe Micro Analysis (EPMA) or the like. In particular, a film forming method that tends to cause anisotropy in a crystal structure such as plating can easily identify the thickness by measuring using Scanning Ion Microscope (SIM) or crystal orientation analysis. When analyzing a thickness of less than 0.1 μm, a precise thickness analysis can be performed by using a Transmission Electron Microscopy (TEM) after using a surface treatment method in which a sample is directly dry etched with ions such as Ar. It can be performed.

It is sectional drawing which shows the structural example of the microstructure apparatus by embodiment of this invention. It is the elements on larger scale of the sealing material of the microstructure apparatus shown in FIG. It is a figure for demonstrating the manufacturing method of a microstructure apparatus. It is a figure which shows another structural example of a 1st metal layer and a 2nd metal layer. It is the elements on larger scale of the sealing material formed when joining a 1st metal layer and a 2nd metal layer, and them. It is a figure for demonstrating another manufacturing method of a microstructure apparatus. It is the elements on larger scale of the sealing material formed when another structural example of a 1st metal layer and a 2nd metal layer and those are joined.

Explanation of symbols

1: Microstructure device 2: First substrate 3: Second substrate 4: Microstructure 5: Sealing material 6: Electrode 7: Wiring conductor 8: Conductive member 10: First metal layer 11: Second metal layer 12: CuSn compound layer

Claims (11)

Bonding the first substrate having a microstructure on the surface, a second substrate having a surface facing the microstructure, and the surfaces facing each other of the first substrate and the second substrate, A sealing material surrounding and sealing the microstructure,
The sealing material is provided in an annular shape along the metal layers between the metal layers and the annular metal layers provided on the opposing surfaces of the first substrate and the second substrate, respectively. A CuSn compound layer containing, as a main component, Cu ₆ Sn ₅ connecting the metal layers , and containing a SnCuNi compound or a SnCuPd compound ,
The microstructure device in which the metal layer provided on the second substrate has a Sn metal layer as a surface layer. An electrode electrically connected to the microstructure provided on the surface of the first substrate;
A wiring conductor provided on at least one of the surface and the inside of the second substrate, a part of which is led to the surface of the second substrate;
A conductive member that electrically connects the electrode and the part of the wiring conductor;
The microstructure device according to claim 1, wherein the conductive member is made of the same material as the sealing material. Bonding the first substrate having a microstructure on the surface, a second substrate having a surface facing the microstructure, and the surfaces facing each other of the first substrate and the second substrate, A manufacturing method of a microstructure device comprising a sealing material surrounding and sealing the microstructure,
A first metal layer forming step of forming an annular first metal layer surrounding the microstructure on the surface of the first substrate;
A second metal layer forming step of forming an annular second metal layer on the surface of the second substrate;
An arranging step of arranging the first metal layer of the first substrate and the second metal layer of the second substrate to face each other;
A heating step of heating and bonding the first metal layer and the second metal layer,
In the first metal layer forming step and the second metal layer forming step, the first metal layer and the second metal layer are formed by laminating a plurality of metal layers, respectively, and a Cu metal layer and tin made of copper are formed. An Sn metal layer comprising: at least one of the first metal layer and the second metal layer;
In the heating step, at least one metal layer constituting the first metal layer and the second metal layer.
Forms a CuSn compound layer mainly composed of Cu ₆ Sn ₅ between at least one metal layer constituting the metal layer, the second metal layer, the surface layer has to have a Sn metal layers,
At least one of the first metal layer and the second metal layer has a Ni metal layer made of nickel or a Pd metal layer made of palladium on the surface layer,
The manufacturing method of the microstructure apparatus which forms the said CuSn compound layer which has a SnCuNi compound or a SnCuPd compound in the said heating process .   In the first metal layer forming step and the second metal layer forming step, the metal layers constituting the first metal layer and the metal layers constituting the second metal layer are formed by a thin film method, plating, or thin film. The manufacturing method of the microstructure device according to claim 3, which is formed by a method and plating.   In the first metal layer forming step or the second metal layer forming step, a laminated structure of a Cu metal layer made of copper and a Sn metal layer made of tin as a part of the first metal layer or the second metal layer The microstructure device according to claim 3, wherein the microstructure device is formed.   The microstructure device according to any one of claims 3 to 5, wherein a ratio of a total thickness of the Sn metal layer to a total thickness of the Cu metal layer is ½ or more and 2/3 or less. The ratio of the total thickness of the Cu metal layer to the total thickness of the Sn metal layer is 1/3 or more and 1/2 or less, and the metal made of nickel, gold, or palladium with respect to the total thickness of the Sn metal layer The microstructure device according to claim 3 , wherein a ratio of a total thickness of the layers is 1/30 or more and 1/20 or less. Bonding the first substrate having a microstructure on the surface, a second substrate having a surface facing the microstructure, and the surfaces facing each other of the first substrate and the second substrate, A manufacturing method of a microstructure device comprising a sealing material surrounding and sealing the microstructure,
A first metal layer forming step of forming an annular first metal layer surrounding the microstructure on the surface of the first substrate;
A second metal layer forming step of forming an annular second metal layer on the surface of the second substrate;
Bonding a solid metal made of copper to the first metal layer or the second metal layer via solder or brazing material;
Arranging the first metal layer and the solid metal to face each other;
A heating step of heating the first metal layer, the second metal layer, and the solid metal to join the first metal layer and the solid metal;
In the first metal layer forming step and the second metal layer forming step, the first metal layer and the second metal layer are formed by laminating a plurality of metal layers, respectively, and the first metal layer and the first metal layer are formed. At least one of the two metal layers has a Sn metal layer made of tin,
In the heating step, a CuSn compound layer mainly composed of Cu ₆ Sn ₅ is formed between at least one metal layer constituting the first metal layer and at least one metal layer constituting the second metal layer. and and said second metal layer, the surface layer has to have a Sn metal layer,
In the first metal layer forming step or the second metal layer forming step, a Ni metal layer made of nickel or a Pd metal layer made of palladium is formed on a surface layer as a part of the first metal layer or the second metal layer. ,
The manufacturing method of the microstructure apparatus which forms the said CuSn compound layer which has a SnCuNi compound or a SnCuPd compound in the said heating process . In the first metal layer forming step and the second metal layer forming step, the metal layers constituting the first metal layer and the metal layers constituting the second metal layer are formed by a thin film method, plating, or thin film. The manufacturing method of the microstructure device according to claim 8, which is formed by a method and plating. Method for manufacturing a microstructure according to the Sn claim 8 or claim 9 ratio of the weight of copper of the solid metal to the weight of tin metal layer is 1/3 to 1/2. The ratio of the weight of the solid metal copper to the weight of the tin of the Sn metal layer is 1/3 or more and 1/2 or less, and the Ni metal layer, the Au metal layer, or Pd with respect to the weight of the tin of the Sn metal layer The method for manufacturing a microstructure device according to claim 8 , wherein a weight ratio of nickel, gold, or palladium in the metal layer is 1/20 or more and 1/10 or less.