JP2014143399A - Substrate and substrate bonding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate suitable for bonding.SOLUTION: A substrate being bonded to other substrate by bringing an activated insulation region on the surface into contact with an activated insulation region on the surface of the other substrate, has a cavity forming a space interconnecting with the surface of the insulation region. The substrate may have a concavity opening to the surface and forming a cavity, and a conductive region arranged contiguously to the concavity and exposed from the surface. The substrate may have a porous layer having multiple cavities on the surface.

Description

  The present invention relates to a substrate and a substrate bonding method.

There is a method of manufacturing a laminated substrate by stacking substrates whose surfaces are activated (see Patent Document 1).
[Patent Document 1] Japanese Translation of PCT Publication No. 2006-517344

  When air or the like is caught between the substrates of the stacked substrates, the cavities expand in the surface direction between the substrates that are adhered by stacking, which is one of the causes of bonding failure and conduction failure. In addition, even if the manufacturing of the multilayer substrate does not result in failure, the air in the multilayer substrate that has expanded due to the heat generated during device driving may deform the substrate and cause characteristic fluctuations or destruction of the circuit elements due to distortion.

  In the first aspect of the present invention, a substrate bonded to another substrate by bringing the insulating region activated on the surface into contact with the insulating region activated on the surface of the other substrate, the insulating region A substrate having a cavity that forms a space communicating with the surface of the substrate is provided.

  In the second aspect of the present invention, a step of forming a cavity for forming a space communicating with the surface on the surface of the insulating region of the substrate, a step of activating the surface of the insulating region, and an activated insulating region Bonding the substrate and the other substrate by bringing the substrate into contact with an activated insulating region on a surface of the other substrate.

  The above summary of the present invention does not enumerate all necessary features of the present invention. A sub-combination of these feature groups can also be an invention.

2 is a cross-sectional view of a light receiving substrate 100. FIG. It is sectional drawing of the process board | substrate 200. FIG. 3 is a cross-sectional view of a multilayer substrate 300. FIG. 4 is a cross-sectional view of a laminated semiconductor device 400. FIG. 5 is a cross-sectional view showing a manufacturing process of the multilayer substrate 300. FIG. 5 is a cross-sectional view showing a manufacturing process of the multilayer substrate 300. FIG. 2 is a plan view of a processing substrate 200. FIG. 5 is a cross-sectional view showing a manufacturing process of the multilayer substrate 300. FIG. 3 is a cross-sectional view of a multilayer substrate 300. FIG. 3 is a cross-sectional view of a multilayer substrate 300. FIG. 2 is a cross-sectional view of a multilayer substrate 301. FIG. 2 is a horizontal sectional view of a multilayer substrate 301. FIG. 12 is a cross-sectional view showing a manufacturing process of the multilayer substrate 302. FIG. 3 is a cross-sectional view of a multilayer substrate 302. FIG. It is sectional drawing which shows the manufacturing process of another laminated substrate. It is sectional drawing of the other laminated substrate 303. FIG. FIG. 6 is a schematic cross-sectional view showing another processing substrate 204. FIG. 6 is a schematic cross-sectional view showing another processing substrate 205. FIG. 6 is a schematic cross-sectional view showing another processing substrate 206. FIG. 6 is a schematic cross-sectional view showing another processing substrate 207. It is a typical perspective view which shows the other process board | substrate 208. FIG. It is a typical perspective view which shows the other process board | substrate 209. FIG. 5 is a schematic cross-sectional view showing a substrate 501. FIG. FIG. 6 is a schematic cross-sectional view showing another substrate 502. It is sectional drawing of the other laminated substrate. It is a flowchart which shows other joining procedures, such as laminated substrate 300. It is sectional drawing of the other laminated substrate 305. FIG. It is sectional drawing of the other laminated substrate 306. FIG. It is sectional drawing of the other laminated substrate 307. FIG. It is a top view of joining surface 159,259.

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

  FIG. 1 is a cross-sectional view of a light receiving substrate 100 that forms a part of the laminated semiconductor device 400. The light receiving substrate 100 includes a support substrate 110, a semiconductor well 130, and a multilayer wiring layer 150.

  The support substrate 110 has a thickness that provides mechanical strength that can withstand the manufacturing process of the light receiving substrate 100. A semiconductor well 130 is disposed on one surface of the support substrate 110 via an insulating layer 120. A plurality of photodiodes 132 arranged in the surface direction of the support substrate 110 are arranged in the semiconductor well 130. A plurality of field effect transistors are formed in the semiconductor well 130 by the gate electrodes 140 and the like formed adjacent to each other.

  The multilayer wiring layer 150 is formed by interlayer insulating materials 152 and wiring materials 154 that are alternately stacked on the surface of the semiconductor well 130. As the wiring material 154, a metal material such as titanium or tungsten can be used. The interlayer insulating material 152 can be formed of silicon oxide or the like.

  The photodiode 132 and the field effect transistor are connected to each other by the multilayer wiring layer 150 to form the light receiving circuit 111. One end of the wiring member 154 in the multilayer wiring layer 150 is electrically connected to the connection pad 160 exposed to the outside on one surface opposite to the support substrate 110. In other words, a plurality of connection pads 160 separated by an interlayer insulating material 152 that is an insulator are exposed on the surface 158 of the light receiving substrate 100 corresponding to the upper surface in the drawing.

  In the light receiving circuit 111, each of the photodiodes 132 corresponds to a pixel, and a field effect transistor performs reset, selection, and amplification for each pixel. The electric charge accumulated by the photodiode 132 upon receiving incident light is output to the outside from the connection pad 160 as a voltage signal through a source follower by a field effect transistor.

  FIG. 2 is a cross-sectional view of the processing substrate 200 that forms part of the stacked semiconductor device 400. The processing substrate 200 includes a support substrate 210, a semiconductor well 230, and a multilayer wiring layer 250.

  The support substrate 210 has a thickness that provides mechanical strength to withstand the manufacturing process of the processing substrate 200. A semiconductor well 230 is disposed on one surface of the support substrate 210. A plurality of field effect transistors are formed in the semiconductor well 230 by the gate electrode 240 formed adjacent to the semiconductor well 230.

  The multilayer wiring layer 250 is formed by interlayer insulating materials 252 and wiring materials 254 that are alternately stacked on the surface of the semiconductor well 230. The plurality of field effect transistors are connected to each other by the multilayer wiring layer 250 to form the processing circuit 211.

  In addition, one end of the wiring member 254 in the multilayer wiring layer 250 is electrically connected to the connection pad 260 exposed to the outside on one surface opposite to the support substrate 210. That is, a plurality of connection pads 260 separated by an interlayer insulating material 252 that is an insulator are exposed on the surface 258 of the processing substrate 200 corresponding to the upper surface in the drawing.

  The connection pads 260 of the processing substrate 200 are connected to the connection pads 160 of the light receiving substrate 100 when stacked with the light receiving substrate 100. Thereby, the processing circuit 211 processes the output signal of the light receiving circuit 111 of the light receiving substrate 100. The processing circuit 211 executes processes such as analog / digital conversion, noise suppression, and file generation.

  Further, the processing substrate 200 has a through electrode 256 fitted into the support substrate 210. One end of the through electrode 256 is electrically connected to the wiring member 254 of the multilayer wiring layer 250. The other end of the through electrode 256 is buried in the support substrate 210 in the illustrated stage.

  FIG. 3 is a cross-sectional view of a multilayer substrate 300 formed in the process of manufacturing a multilayer semiconductor device 400 that can be used as an image sensor. In the laminated substrate 300, the light receiving substrate 100 is laminated on the processing substrate 200 with the front and back reversed with respect to the state shown in FIG. 1. In the multilayer substrate 300, the connection pads 160 of the light receiving substrate 100 and the connection pads 260 of the processing substrate 200 are in contact with each other and are electrically connected.

  When the light receiving substrate 100 and the processing substrate 200 are stacked, the light receiving substrate 100 and the processing substrate 200 are aligned based on the positional deviations of several predetermined alignment indexes on each substrate. In the alignment, for example, the yield of the multilayer substrate 300 can be improved by a global alignment method that calculates a position where the overall positional deviation is minimized. Further, the alignment accuracy can be further improved by adding offset correction, rotation correction, orthogonality correction, scaling correction, and the like based on the position of the alignment index.

  As the alignment index, the connection pads 160 and 260 themselves may be used, or wirings and substrates formed on the light receiving substrate 100 and the processing substrate 200 may be used. Further, alignment marks provided on the light receiving substrate 100 and the processing substrate 200 may be used for the purpose of use in alignment.

  FIG. 4 is a cross-sectional view of a laminated semiconductor device 400 manufactured by further processing the laminated substrate 300. In the laminated semiconductor device 400, the support substrate 210 of the processing substrate 200 is thinned, and the bump 220 is provided at the lower end of the through electrode 256 exposed on the lower surface in the drawing. Thereby, the laminated semiconductor device 400 can be electrically connected to another substrate, a lead frame, or the like.

  In the laminated semiconductor device 400, the support substrate 110 of the light receiving substrate 100 is removed, and the light shielding layer 170, the planarization layer 172, the organic planarization layers 174 and 182, the on-chip color filter 180, and the on-chip color filter 180 are formed on the exposed insulating layer 120. A chip lens 190 and the like are sequentially stacked.

  Thereby, the photodiode 132 of the light receiving substrate 100 receives the light incident through the on-chip lens 190 and the on-chip color filter 180 without passing through the multilayer wiring layer 150. As described above, the stacked semiconductor device 400 forms a back-illuminated image sensor.

  In the laminated semiconductor device 400, the light receiving substrate 100 and the processing substrate 200 are electrically coupled through connection pads 160 and 260. Therefore, the electric charge generated by the light incident on the photodiode 132 in the light receiving substrate 100 is transferred as a voltage signal to the processing circuit 211 on the processing substrate 200 side, and further processed through digital conversion and the like, and then from the bump 220 to the outside. Is output.

  Each of the light receiving substrate 100 and the processing substrate 200 has the structure shown in FIG. 1 or FIG. 2 repeatedly in each plane direction. Therefore, by stacking the light receiving substrate 100 and the processing substrate 200, a large number of stacked semiconductor devices 400 are manufactured at once.

  Therefore, the laminated substrate 300 is cut by dicing into a large number of dies. Each of the dies thus obtained has a high yield and a high integration density because it is manufactured by stacking the light receiving substrate 100 and the processing substrate 200.

  5 to 10 are schematic cross-sectional views showing in detail the manufacturing process of the multilayer substrate 300 while paying attention to the bonding stage of the light receiving substrate 100 and the processing substrate 200. FIG. In the drawing, the light receiving substrate 100 and the processing substrate 200 are simplified and shown by interlayer insulating materials 152 and 252 which are insulators and connection pads 160 and 260 which are conductors. Unless otherwise specified, the light receiving substrate 100 and the processing substrate 200 are bonded in an atmospheric environment.

  As shown in FIG. 5, in manufacturing the multilayer substrate 300, the surface of the light receiving substrate 100 where the connection pads 160 are exposed in the interlayer insulating material 152 and the connection pads 260 are exposed in the interlayer insulating material 252 of the processing substrate 200. The joined surfaces are joined. As will be described subsequently, in joining the light receiving substrate 100 and the processing substrate 200, the interlayer insulating materials 152 and 252 are first joined together, and then the connection pads 160 and 260 are joined together.

  In joining the light receiving substrate 100 and the processing substrate 200, first, as shown in FIG. 6, a depressed portion 257 is formed in the processing substrate 200. The depressed portion 257 is formed by etching the interlayer insulating material 252 in a region adjacent to the connection pad 260.

  The formed depressed portion 257 opens toward the surface 258 of the processing substrate 200. Further, the formed depression 257 is adjacent to the connection pad 260 and surrounds the connection pad 260, as shown in FIG. As a result, a cavity communicating with the surface 258 of the processing substrate 200 is formed inside the processing substrate 200.

  Next, as shown in FIG. 8, the surfaces 158 and 258 of the light receiving substrate 100 and the processing substrate 200 are smoothed to form bonding surfaces 159 and 259 on the surfaces of the interlayer insulating materials 152 and 252. The joint surfaces 159 and 259 can be smoothed by polishing, but etching may be used in combination prior to polishing. The bonding surfaces 159 and 259 are preferably smoothed to less than 1 nm, respectively. The smoothed light-receiving substrate 100 and processed substrate 200 are dried after removing residues generated by polishing by washing.

  Note that, when the bonding surfaces 159 and 259 are polished, the connection pads 160 and 260 are caused by a difference in physical properties between the interlayer insulating materials 152 and 252 that form the bonding surfaces 159 and 259 and the metal that forms the connection pads 160 and 260. Therefore, the tips of the connection pads 160 and 260 sink from the joint surfaces 159 and 259 into the interlayer insulating materials 152 and 252.

  Further, the metal connection pads 160 and 260 are inevitably elastically deformed by the pressure when being polished. For this reason, the front end surfaces of the connection pads 160 and 260 after polishing are not flat, and the center is recessed.

Next, the bonding surfaces 159 and 259 of the light receiving substrate 100 and the processing substrate 200 are activated. The bonding surfaces 159 and 259 can be activated by treating the surfaces of the bonding surfaces 159 and 259 with, for example, reactive ion etching or inductively coupled plasma. Further, the activated bonding surfaces 159 and 259 may be immersed in a solution such as NH ₄ OH, NH ₄ F, and HF for a short time.

  As shown in FIG. 9, the light-receiving substrate 100 and the processing substrate 200 that have activated the bonding surfaces 159 and 259 formed on the surfaces of the interlayer insulating materials 152 and 252 that are insulators are made to face each other. The laminated substrate 300 is formed by being naturally adsorbed and bonded. Further, by allowing the light receiving substrate 100 and the processing substrate 200 to stand for about 24 hours while being adsorbed to each other, the bonding strength between the light receiving substrate 100 and the processing substrate 200 can be applied to processing such as chemical mechanical polishing of the support substrates 110 and 210. It will be tolerable.

  Note that the depressed portion 257 formed in the interlayer insulating material 252 of the processing substrate 200 is also adjacent to the bonding surface 259. Therefore, bubbles sandwiched between the joining surfaces 159 and 259 in the joining process are pushed into the depressed portion 257 by the joining surfaces 159 and 259 that adsorb each other. Therefore, the generation of voids that spread thinly between the closely bonded surfaces 159 and 259 is prevented.

  In the stage shown in FIG. 9, a gap remains between the connection pads 160 and 260 that have sunk from the joint surfaces 159 and 259. Further, as described above, the tip surfaces of the connection pads 160 and 260 have a shape in which the center is recessed, so that the gap between the connection pads 160 and 260 is wider at the center. For this reason, sufficient electrical connection is not yet formed between the light receiving substrate 100 and the processing substrate 200.

  Therefore, by performing a reflow process on the multilayer substrate 300, as shown in FIG. 10, the connection pads 160 and 260 are integrated, and the connection portion 360 is formed. Here, by forming the connection pads 160 and 260 from a material that melts at a low temperature such as indium and tin-silver alloy, the multilayer substrate 300 can be reflowed at a low temperature of 200 degrees or less.

  Further, as described above, the depressed portion 257 is arranged adjacent to the periphery of the connection pads 160 and 260. Therefore, when the connection pads 160 and 260 are melted by reflow and condensed by surface tension, the air remaining in the depressions of the connection pads 160 and 260 moves to the depressed portion 257. As a result, the reflow-treated connection pads 160 and 260 form a dense connection portion 360 without voids.

  In view of the above functions, the depressed portion 257 may be formed on the light receiving substrate 100 as long as it is adjacent to the connection pads 160 and 260 forming the connection portion 360. Further, the depressed portion 257 may be formed on both the light receiving substrate and the processing substrate 200.

  Further, the depressed portion 257 does not have to be a complete ring as long as it is adjacent to the connection pads 160 and 260 forming the connection portion 360. Further, the depth of the depressed portion 257 can also be appropriately selected depending on the anticipated amount of stored air.

  In this way, by manufacturing the laminated substrate 300 by bonding the processing substrate 200 provided with the depressed portion 257 on the surface 258, voids caused by air sandwiched between the bonding surfaces 159 and 259 and the connection pads 160 and 260 are generated. It can prevent expanding in the surface direction. Thereby, it is possible to form a connection portion 360 having high strength and good electrical characteristics. In addition, the workability is low, and the joining work in a vacuum environment that affects the manufacturing cost and throughput is not necessary, which contributes to the improvement of the productivity of the stacked semiconductor device 400.

  The depressed portion 257 may be provided on the light receiving substrate 100 side. Further, the depressed portion 257 may be provided on both the light receiving substrate 100 and the processing substrate 200.

  FIG. 11 is a cross-sectional view for explaining the manufacturing process of another laminated substrate 301. The laminated substrate 301 is different from the laminated substrate 300 described up to FIG. 10 in that a recessed groove 157 is also formed on the light receiving substrate 100 side. As a result, a cavity communicating with the surface 158 is formed inside the light receiving substrate 100. Since the remaining part is common with the laminated substrate 300, the overlapping description is omitted.

  FIG. 12 is a horizontal sectional view of the multilayer substrate 301, and shows a cross section obtained by cutting the multilayer substrate 301 at the joint surface between the light receiving substrate 100 and the processing substrate 200. The recessed groove 157 formed in the light receiving substrate 100 in the multilayer substrate 301 allows the recessed portions 257 formed around the connection portion 360 to communicate with each other. Further, some of the recessed grooves 157 communicate with the outside at the side end surface of the multilayer substrate 301. Accordingly, even when a large amount of air is caught when the light receiving substrate 100 and the processing substrate 200 are joined, they are discharged to the outside through the recessed groove 157.

  In this way, by fabricating the laminated substrate 301 by bonding the light receiving substrate 100 having the recessed groove 157 and the processing substrate 200 having the recessed portion 257, the internal pressure of the recessed portion 257 is increased, and the bonding surfaces 159 and 259 are formed. Preventing self-adsorption is prevented. Note that the depressed groove 157 may be provided in the processing substrate 200 and the depressed portion 257 may be provided in the light receiving substrate 100.

  FIG. 13 is a cross-sectional view showing a manufacturing process of another laminated substrate 302. In the processing substrate 201 that forms the multilayer substrate 301, a vertical hole 261 is formed in the approximate center of the connection pad 260. As a result, a cavity that communicates with the surface 258 is formed in the processing substrate 200.

  On the other hand, in the processing substrate 201, the depressed portion 257 around the connection pad 260 is removed. These points are different from the processing substrate 200 of the multilayer substrates 300 and 301. Since the remaining part is the same as that of the processing substrate 200, redundant description is omitted.

  The vertical hole 261 as described above can be formed by etching the center of the connection pad 260. Further, the vertical hole 261 may penetrate the connection pad 260 in the thickness direction. Thereby, the vertical hole 261 is disposed adjacent to the connection pad 260.

  FIG. 14 is a cross-sectional view of a multilayer substrate 302 formed by bonding the light receiving substrate 100 and the processing substrate 201 shown in FIG. In addition, since the same process as the stage demonstrated with reference to FIGS. 6-9 is performed between the state shown in FIG. 13 and the state shown in FIG. 14, the overlapping description is abbreviate | omitted.

  In the processing substrate 201, a vertical hole 261 is formed near the center of the connection pad 260. Therefore, when the laminated substrate 302 formed by bonding the light receiving substrate 100 and the processing substrate 201 is subjected to a reflow process, the air sandwiched between the tips of the connection pads 160 and 260 is taken into the vertical holes 261. In this way, by bonding the processing substrate 201 having the vertical holes 261 to manufacture the multilayer substrate 302, the voids are prevented from spreading in the surface direction between the connection pads 160 and 260, and the light receiving substrate 100 and the processing substrate 201 are connected. A good electrical connection is formed between the two.

  Note that the vertical hole 261 communicates to some extent with the air that is caught between the interlayer insulating materials 152 and 252 of the light receiving substrate 100 and the processing substrate 201. However, the air sandwiched between the light receiving substrate 100 and the processing substrate 200 may be more efficiently accommodated by using the depressed groove 157 and the depressed portion 257 shown in FIG.

  In the above example, the vertical holes 261 are formed in the connection pads 260 of the processing substrate 201. However, even if the vertical holes 261 are formed in the connection pads 160 of the light receiving substrate 100, the expansion of voids can be suppressed as in the above example. Further, the vertical holes 261 may be formed in both the connection pads 160 of the light receiving substrate 100 and the connection pads 260 of the processing substrate 201.

  FIG. 15 is a cross-sectional view of a processing substrate 202 on which another laminated substrate is formed. The processing substrate 202 shown in FIG. 15 has a surface 258 formed of a porous body having a plurality of opening holes 255. Thereby, a plurality of cavities communicating with the surface 258 are formed in the processing substrate 202. A part of the opening hole 255 is disposed adjacent to the connection pad 260, and the other part is scattered on the surface of the interlayer insulating material 252 that forms the bonding surface 259.

  As a result, the area of the bonding surface when the processing substrate 202 is bonded to another substrate is slightly reduced. However, even when air is caught when the light receiving substrate 100 and the processing substrate 202 are bonded, voids are formed on the bonding surface. It is prevented from spreading in the surface direction. Therefore, the interlayer insulating materials 152 and 252 and the connection pads 160 and 260 can be favorably bonded.

  Note that the surface of the light receiving substrate 100 stacked on the processing substrate 202 may be formed of a porous body having a plurality of opening holes 255. Also in the above embodiment, the porous body having the opening hole 255 may be combined with the depressed groove 157, the depressed portion 257, the vertical hole 261, and the like shown in FIG.

  FIG. 16 is a cross-sectional view showing the manufacturing process of another laminated substrate 303. The illustrated laminated substrate 303 includes a fitting hole 153 formed in the light receiving substrate 101 and a fitting protrusion 253 formed in the processing substrate 203 in addition to the laminated substrate 301 shown in FIGS. 11 and 12. Accordingly, when the light receiving substrate 101 and the processing substrate 203 are joined, the alignment step can be omitted by fitting the fitting hole 153 and the fitting protrusion 253 together. In addition, as long as the light receiving substrate 101 and the processing substrate 203 have complementary portions, the shape and number of the other portions of the fitting hole 153 and the fitting protrusion 253 are not limited.

  FIG. 17 is a schematic cross-sectional view of another processing substrate 204 that can form a laminated substrate. The processing substrate 204 shown in FIG. 17 has a recess 551 formed on the surface 258 together with the connection pad 260 without filling the connection pad 260. The depressed portion 551 can be formed, for example, by processing the interlayer insulating material 252 again by photolithography after the connection pad 260 is formed.

  The recessed portion 551 of the processing substrate 204 has a larger capacity than the recess formed at the tip of the connection pad 260. Therefore, the air left between the substrates when the processing substrate 204 is bonded to the light receiving substrate 100 is accommodated in the depressed portion 551. Thereby, even if the temperature of the laminated substrate after bonding rises, an increase in internal pressure due to the expanded air is suppressed. Therefore, distortion of the multilayer substrate due to air left in the multilayer substrate is also reduced.

  As shown in the figure, the depressed portion 551 having the same shape as the connection pad 260 can be formed by using a resist material, an etchant, or the like used when forming the connection pad 260 as it is. Needless to say, the shape of the depressed portion 551 can be variously modified. The shape of the depressed portion 551 may be a groove that allows the plurality of connection pads 260 to communicate with each other, or may be a groove that communicates to the side peripheral surface of the processing substrate 204 and allows internal air to escape to the outside.

  Furthermore, the depressed portion 551 may have the same shape as the depressed groove 157, the opening hole 255, the fitting hole 153, the fitting protrusion 253, and the like exemplified up to FIG. Furthermore, the depressed portion 551 shown in the figure may be combined with the depressed groove 157, the opening hole 255, the fitting hole 153, the fitting protrusion 253, and the like.

  Further, the arrangement of the depressions 551 can be variously changed within a range that does not interfere with elements, wirings, and the like formed on the processing substrate 204. Further, when a plurality of depressions 551 are provided on the processing substrate 204, they may have the same size or different shapes and sizes. Furthermore, a depressed portion 551 may be provided also on the light receiving substrate 100 side.

  FIG. 18 is a schematic cross-sectional view of another processing substrate 205 capable of forming a laminated substrate. In FIG. 18, focusing on one connection pad 260 on the processing substrate 205, the drawing is enlarged as compared with the other drawings.

  The processing substrate 205 has a cavity 552 formed adjacent to the connection pad 260. The cavity portion 552 communicates with the surface 258 of the processing substrate 206 along the connection pad 260, but the end portion of the cavity portion 552 itself does not open to the surface 258 of the processing substrate 205, and the inside of the interlayer insulating material 252 Open to. Thus, the cavity 552 that accommodates the air remaining in the multilayer substrate can be formed without reducing the bonding area of the processing substrate 205 to the light receiving substrate 100.

  The cavity 552 as described above can be formed by processing the interlayer insulating material 252 using an etchant that selectively etches the interlayer insulating material 252 while the surface 258 of the interlayer insulating material 252 is protected with a resist or the like. . The shape and arrangement of the cavity 552 are not limited to the example shown in the drawing, as in the case described with reference to FIG.

  FIG. 19 is a schematic cross-sectional view of another processing substrate 206 that can form a laminated substrate. In the processing substrate 206, one end of the through electrode 262 forms a connection pad when the processing substrate 206 is bonded.

  The through electrode 262 has the same layout as the connection pads 260 of the processing substrate 204 shown in FIG. 17 in the surface direction of the processing substrate 206. However, the through electrode 262 penetrates the interlayer insulating material 252 in the thickness direction, for example. In addition, the through electrode 262 may penetrate to the support substrate 210 and may pass through to the back surface of the processing substrate 206.

  The processing substrate 206 further includes a vertical hole 553. The vertical holes 553 are formed along each of the through electrodes 262 in the thickness direction of the processing substrate 206. Such a vertical hole 553 can be formed by, for example, forming the through electrode 262 and then processing the interlayer insulating material 252 again by photolithography. In the example of FIG. 19, the vertical holes 553 are formed close to the through electrodes 262, but a plurality of vertical holes 553 are formed so as to surround the through electrodes 262, or a predetermined interval is provided between the plurality of through electrodes 262. A plurality of vertical holes 553 may be formed at intervals, or may be formed at a position with little influence on the circuit, such as on a scribe line.

  FIG. 20 is a schematic cross-sectional view of another processing substrate 207 that can form a laminated substrate. The processing substrate 207 includes a through electrode 262 in the same manner as the processing substrate 206 shown in FIG. 19, and further has a vertical hole 263 that penetrates the inside of the through electrode 262 in the longitudinal direction.

  Such a vertical hole 263 can be formed simultaneously with the formation of the through-electrode 262, for example, when the conductive material for forming the through-electrode 262 is embedded and the deposition of the conductive material is stopped before the via is completely filled. Further, as shown in FIG. 4, when the support substrate 210 is thinned, the vertical hole 263 can be penetrated to the back surface of the processing substrate 207.

  The vertical holes 553 and 263 formed in the processing substrates 206 and 207 shown in FIGS. 19 and 20 have a larger capacity than the recessed portions 257 and the like shown in FIG. Therefore, even if the processing substrates 206 and 207 are bonded to the light receiving substrate 100 and the air accommodated in the vertical holes 553 and 263 expands due to the temperature change after bonding, the stress that distorts the multilayer substrate is relieved.

  Further, when the vertical holes 553 and 263 are penetrated to the back surfaces of the processing substrates 206 and 207, air sandwiched between the substrates when the processing substrates 206 and 207 are bonded can be discharged to the outside of the multilayer substrate. Therefore, the processing substrates 206 and 207 can be brought into close contact with the light receiving substrate 100, and thermal expansion of air after bonding can be prevented from distorting the multilayer substrate.

  FIG. 21 is a schematic perspective view of another processing substrate 208 that can form a laminated substrate. FIG. 21 shows a state where a plurality of processing circuits 211 are formed on one wafer.

  By bonding the processing substrate 208 to a wafer on which a plurality of light receiving circuits 111 are formed, a plurality of stacked semiconductor devices 400 can be manufactured collectively. The plurality of stacked semiconductor devices 400 formed by bonding are cut into individual dies by cutting on scribe lines formed between the processing circuits 211 in the processing substrate 208.

  FIG. 20 is a schematic diagram. In the manufacture of a semiconductor device, a large number of processing circuits 211 are formed on one wafer. Further, the processing circuit 211 is arranged on the wafer such that the individual dies cut by dicing have the same rectangular shape.

  The illustrated processing substrate 208 further includes a recessed groove 554 formed along the scribe line. The recessed groove 554 can be formed, for example, by partially executing dicing, that is, by cutting the processing substrate 207 shallowly. Further, the surface 558 of the processing substrate 208 may be etched along the scribe line by photolithography.

  The recessed groove 554 passes through the individual gaps of the plurality of processing circuits 211 and communicates with the edge of the processing substrate 207. Therefore, when the processing substrate 207 is bonded to the light receiving substrate 100, the air sandwiched between the substrates is discharged to the outside of the multilayer substrate through the recessed groove 554.

  In addition, as indicated by a dotted line in the figure, a narrow groove 555 that communicates with each of the recessed grooves 554 from each of the processing circuits 211 may be further formed. Thus, the air sandwiched between the regions where the processing circuit 211 is formed can be guided to the recessed groove 554 so that the processing circuit 211 is brought into close contact with the light receiving circuit 111.

  The recessed groove 554 formed on the scribe line disappears with the dicing of the laminated substrate. Therefore, the effective bonding area of the processing substrate 208 is not reduced by the recessed groove 554. The shape, arrangement, and the like of the recessed groove 554 can be variously changed. Furthermore, any or all of the recessed portion 257, the recessed groove 157, the vertical hole 261, the opening hole 255, the fitting hole 153, and the fitting protrusion 253 exemplified above may be formed in combination with the recessed groove 554.

  FIG. 22 is a schematic perspective view of another processing substrate 209 that can form a laminated substrate. The processing substrate 209 has a plurality of through holes 556 formed on the scribe line. Each of the through holes 556 penetrates the processing substrate 209 in the thickness direction and reaches the back surface of the processing substrate 209. Thereby, when the processing substrate 209 is bonded to the light receiving substrate 100, the air sandwiched between the substrates can be excluded to the outside of the multilayer substrate through the through hole 556.

  Further, the through hole 556 formed on the scribe line disappears with the dicing of the laminated substrate. Therefore, by providing the through hole 556, the effective bonding area of the processing substrate 209 is not reduced. The shape and arrangement of the through holes 556 can be variously changed. Furthermore, any or all of the recessed portion 257, the recessed grooves 157 and 554, the vertical hole 261, the opening hole 255, the fitting hole 153, and the fitting protrusion 253 exemplified above may be formed in combination with the through hole 556. .

  FIG. 23 is a schematic cross-sectional view of a substrate 501 that can form a laminated substrate by bonding to another substrate 500. The substrate 501 has a plurality of opening holes 557 opened on the surface, and a porous layer is formed on the surface 558.

  The light receiving substrates 100 and 101 and the processing substrates 201 to 209 described so far include the connection pads 160 and 260 or the through electrodes 262 on the surfaces 158 and 258 of the bonding surfaces, respectively. On the other hand, the substrate 501 does not have the connection pads 160 and 260 and the through electrode 262.

  However, even in the substrate 501 that does not have the connection pads 160 and 260 and the through-electrode 262, the voids are prevented from expanding in the surface direction by bonding after forming a cavity communicating with the surface 558 of the substrate. The influence of air remaining in the substrate can be suppressed.

  In the case of the substrate 501, a porous body having a large number of opening holes 557 on the surface 558 is formed. Accordingly, when the substrate 501 is bonded to another substrate 500 to form a laminated substrate, the air sandwiched between the substrates is accommodated in the opening hole 557, and the formation of voids that continuously expand can be prevented. Further, when the temperature of the laminated substrate rises, the pressure of air remaining in the laminated substrate is dispersed in the opening holes 557, and an increase in pressure that distorts the laminated substrate is suppressed.

  In the substrate 501, the opening hole 557 may be deformed into the recessed portions 257 and 551, the recessed groove 157, the fitting hole 153, the fitting protrusion 253, and the like. Further, the illustrated opening hole 557 and the recessed groove 157, the opening hole 255, the fitting hole 153, the fitting protrusion 253, and the like may be combined and formed simultaneously. Furthermore, a cavity may be provided by forming a recessed groove 157, an opening hole 255, a fitting hole 153, a fitting protrusion 253, and the like on another substrate 500 to be bonded to the substrate 501.

  FIG. 24 is a schematic perspective view of a substrate 502 on which a laminated substrate can be formed. Similarly to the substrate 501, the substrate 502 is bonded to another substrate 500 on the surface 558 without the connection pads 160 and 260 and the through electrode 262 to form a laminated substrate.

  The substrate 502 has a lattice-shaped recessed groove 554 on the surface 558 having the same layout as the processing substrate 208 shown in FIG. The recessed groove 554 may be formed by the same processing as dicing, or may be formed by etching. The recessed groove 554 communicates with the edge of the substrate 502.

  Therefore, the air sandwiched between the substrates is discharged through the recessed groove 554 by bonding to the substrate 500. Further, the recessed groove 554 can be removed by dicing by arranging the recessed groove 554 in accordance with the scribe line of the substrate 502 itself or the scribe line of another substrate 500 to be bonded. Therefore, by providing the recessed groove 554, the effective bonding area of the substrate 502 is not reduced.

  Also in the substrate 502, the recessed groove 554 may be deformed into recessed portions 257 and 551, a recessed groove 157, a fitting hole 153, a fitting protrusion 253, and the like. Further, the recessed groove 554 shown in the figure, and the recessed groove 157, the opening hole 255, the fitting hole 153, the fitting protrusion 253, and the like may be combined and formed simultaneously. Furthermore, a hollow portion may be provided by forming a recessed groove 157, an opening hole 255, a fitting hole 153, a fitting protrusion 253, and the like on another substrate 500 to be bonded to the substrate 502.

  FIG. 25 is a cross-sectional view of another laminated substrate 304. The laminated substrate 304 has the same structure as the laminated substrate 300 shown in FIGS. 5 to 10 except for portions to be described below. Therefore, common elements are denoted by the same reference numerals, and redundant description is omitted.

  The laminated substrate 304 is common to the laminated substrate 300 in that the depressed portion 257 is provided around the connection portion 360. However, as indicated by the dotted line A in the connection portion 360, in the laminated substrate 304, a depressed portion 257 is also formed around the connection pad 160 on the light receiving substrate 100 side. Therefore, in the laminated substrate 304, the size of the depressed portion 257 is large in the thickness direction of the laminated substrate 304.

  Thereby, when the connection portion 360 having a higher thermal expansion coefficient than the surrounding interlayer insulating materials 152 and 252 expands due to a temperature change, the force acting on the joint portion between the light receiving substrate 100 and the processing substrate 200 is reduced. That is, the stress generated by the thermal expansion of the connecting portion 360 acts on the joint portion after exceeding the depressed portion 257. Therefore, due to the deformation of the interlayer insulating materials 152 and 252 in the meantime, the force to peel off the bond between the light receiving substrate 100 and the processing substrate 200 is alleviated. Thereby, the stability with respect to the temperature change of the multilayer substrate 304 is improved.

  The effect of preventing peeling as described above is enhanced by increasing the width of the depressed portion 257. On the other hand, as shown in FIGS. 5 to 10, the same effect can be obtained even when the depressed portion 257 is provided on one of the light receiving substrate 100 and the processing substrate 200. Although the connection portion 360 formed by the connection pads 160 and 260 has been described, other elements that exist on the bonding surface of the multilayer substrate 304 and have a coefficient of thermal expansion different from that of the interlayer insulating materials 152 and 252, for example, through electrodes Even if the depressed portion 257 is provided around the periphery, peeling can be similarly prevented.

  FIG. 26 is a flowchart showing one of procedures for manufacturing the laminated substrate 300 and the like. First, a semiconductor element is formed on a substrate material such as a silicon wafer, and the light receiving substrate 100, the processing substrate 200, and the like are manufactured (step S101).

  Next, conductive regions to be connection pads 160 and 260 are formed in each of the light receiving substrate 100 and the processing substrate 200 (step S102). Each of the conduction regions is formed so that the end surfaces are exposed on the surfaces of the bonding surfaces 159 and 259 in each of the light receiving substrate 100 and the processing substrate 200.

  Next, depressions 175 and 257 adjacent to the conductive regions are formed in the interlayer insulating materials 152 and 252 of the light receiving substrate 100 and the processing substrate 200 (step S103). Further, in this step, a recessed groove 157, a narrow groove 555, and the like that allow the recessed portions 175 and 257 to communicate with the peripheral portions of the light receiving substrate 100 and the processing substrate 200 are also formed.

  Next, after the bonding surfaces 159 and 259 are activated, the light receiving substrate 100 and the processing substrate 200 are overlaid (step S104). Here, the gas sandwiched between the conductive regions connected between the light receiving substrate 100 and the processing substrate 200 is pushed out into the depressions 175 and 257 adjacent to the conductive regions.

  Further, the gas remaining between the light receiving substrate 100 and the processing substrate 200 is degassed through the recessed portions 175 and 257, the recessed groove 157, the narrow groove 555, and the like (step S105). The light receiving substrate 100 and the processing substrate 200 can be deaerated through the depressed portions 175 and 257, the depressed groove 157, the narrow groove 555, and the like by performing the superposition in step S104 in a reduced pressure environment or a vacuum environment, for example.

  Further, by performing the superposition in step S104 in the atmosphere or in an inert gas atmosphere and then heating, the space between the superposed light receiving substrate 100 and the processing substrate 200 can be deaerated. In addition, since moisture may be deposited from the exposed metal, oxide, or the like of the bonding surfaces 159 and 259 by heating, the light-receiving substrate 100 and the processing substrate 200 stacked in a vacuum are also deaerated by heating. It is preferable to

  The light receiving substrate 100 and the processing substrate 200 that have been deaerated after being superposed in this manner (step S104) are heated to a temperature at which the connection pads 160 and 260 are fused to form the connection portion 360, thereby forming a connection portion (see FIG. Step S106). By these series of procedures, the connection portion is formed after the gas between the light receiving substrate 100 and the processing substrate 200 is removed, so that a dense connection portion 360 that does not include bubbles can be formed.

  In addition, the bonding strength at the connection portion 360 and the interlayer insulating materials 152 and 252 is also increased. Furthermore, in step S105, the steam 360 is degassed by heating, whereby oxidation of the connection portion 360 containing metal can be prevented.

  Note that at least one of the substrates to be stacked may be provided with an independent conductive region that is not connected to another circuit, a depressed portion adjacent to the independent conductive region, and the like. As a result, water vapor or the like generated between the light receiving substrate 100 and the processing substrate 200 when heated is absorbed by the independent conduction region, and the connection pads 160 and 260 forming the connection portion 360 can be prevented from being oxidized. .

  In addition, a recess or the like may be formed only around the independent conduction region without forming a recess or the like around the connection portion 360. In this case, the gas between the connection pads 160 and 260 can be caused to flow into the depressed portion around the independent conduction region by the depressed groove 554 or the like. Further, in this case, when the light receiving substrate 100 and the processing substrate 200 are overlapped in the atmosphere, for example, there is no place where the gas is collected around the connection portion 360, so that the connection portion 360 is prevented from being oxidized by the accumulated gas. Can do.

  FIG. 27 is a cross-sectional view of another laminated substrate 305. The laminated substrate 305 has the same structure as the laminated substrate 304 shown in FIG. Common elements are given the same reference numbers and redundant description is omitted.

  The light receiving substrate 100 and the processing substrate 200 forming the multilayer substrate 305 have barrier layers 164 and 264 formed between the connection pads 160 and 260 forming the connection portion 360 and the interlayer insulating materials 152 and 252. The barrier layers 164 and 264 are provided for the purpose of preventing the metal such as copper forming the connection pads 160 and 260 from diffusing into the light receiving substrate 100 or the processing substrate 200.

  In the laminated substrate 305, at least a part of the barrier layers 164 and 264 is removed inside the depressed portion 257. As a result, in the laminated substrate 305, the connection part 360 is exposed inside the depressed part 257 without being blocked by the barrier layers 164 and 264. Therefore, before the connection portion 360 is formed, the gas between the connection pads 160 and 260 can be pushed out to the depressed portion 257 without being blocked by the barrier layers 164 and 264. Thereby, the multilayer substrate 305 has the dense connection part 360 without a void.

  Note that the barrier layers 164 and 264 may not be removed over the entire circumference of the connection portion 360 as long as the connection portion 360 and the cavity of the depressed portion 257 communicate with each other. In the illustrated example, the depressed portion 257 is provided on the processing substrate 200 side, but may be provided on the light receiving substrate 100 side, or may be provided on both the light receiving substrate 100 and the processing substrate 200.

  FIG. 28 is a cross-sectional view of another laminated substrate 306. The laminated substrate 306 has the same structure as the laminated substrate 304 shown in FIG. Common elements are given the same reference numbers and redundant description is omitted.

The light receiving substrate 100 and the processing substrate 200 that form the multilayer substrate 306 are different in the distance between the connection pads 160 and 260 that form the connection portion 360. For this reason, in the connection portion 363 on the right side in the drawing, a horizontal shift W _d1 is generated between the portion on the light receiving substrate 100 side and the portion on the processing substrate 200 side.

However, in the multilayer substrate 306, since the depressed portion 257 has a width W _t1 larger than the shift W _d1 , the boundary between the connection pads 160 and 260 and the interlayer insulating materials 152 and 252 is inside the depressed portion 257, respectively. Exposed. Thereby, in the multilayer substrate 306, the gas between the connection pads 160 and 260 can be pushed out to the depressed portion 257 before the connection portion 360 is formed. Therefore, the multilayer substrate 306 has a dense connection portion 360 without voids.

  FIG. 29 is a cross-sectional view of another laminated substrate 307. The laminated substrate 307 has the same structure as the laminated substrate 306 shown in FIG. 28 except for the portions described below. Common elements are given the same reference numbers and redundant description is omitted.

In the light receiving substrate 100 and the processing substrate 200 that form the multilayer substrate 307, the positions of the connection pads 160 and 260 that form the connection portion 360 are displaced in the entire surface direction of the multilayer substrate 307, causing W _d2 . On the other hand, the depressed portions 175 and 257 have a width W _t2 wider than the shift W _d2 . Thereby, in the laminated substrate 307, the gas between the connection pads 160 and 260 can be pushed out to the depressions 175 and 257 before the connection portion 360 is formed. Therefore, the multilayer substrate 307 has a dense connection portion 360 without voids.

However, when the width W _t2 of the depressions 175 and 257 is increased, the bonding area of the interlayer insulating materials 152 and 252 bonded at the bonding surfaces 159 and 259 of the light receiving substrate 100 and the processing substrate 200 is decreased, and the bonding strength is decreased. To do. On the other hand, in the multilayer substrate 307, the reduction of the bonding area of the interlayer insulating materials 152 and 252 is suppressed by limiting the range in which the depressed portions 175 and 257 are in contact with the connection portion 360.

  FIG. 30 is a plan view showing a layout of the bonding surfaces 159 and 259 of the light receiving substrate 100 and the processing substrate 200 in the multilayer substrate 307. In the light receiving substrate 100, the depressed portion 175 is formed on the left side of the connection pad 160 serving as the connection portion 360 in the drawing, and is not formed on the right side in the drawing. Further, in the processing substrate 200, the depressed portion 257 is formed on the right side in the drawing of the connection pad 260 to be the connection portion 360, and is not formed on the left side in the drawing.

  However, the depressions 175 and 257 both extend to more than half along the upper and lower surfaces of the connection pads 160 and 260 in the drawing. Accordingly, when the light receiving substrate 100 having the depressed portion 257 and the processing substrate 200 are bonded, the depressed portion 175 on the light receiving substrate 100 side and the depressed portion 257 on the processing substrate 200 side communicate with each other.

Further, the multilayer substrate 307 has a width W _t2 wider than the displacement W _d2 of the connection pads 160 and 260. Thus, when the light receiving substrate 100 is bonded to the processing substrate 200, the depressed portion 175 provided on the light receiving substrate 100 includes the end surface of the connection pad 260 provided on the processing substrate 200 to the edge, and the processing substrate The depressed portion 257 provided in 200 includes the end surface of the connection pad 160 provided in the light receiving substrate 100 to the edge.

  Therefore, in the laminated substrate 307, when the depressions 175 and 257 are combined, a hollow portion that goes around the connection portion 360 is formed, and the gas between the connection pads 160 and 260 is reliably received. Thereby, the multilayer substrate 307 has a dense connection portion 360 without voids. In addition, since the areas of the depressions 175 and 257 are limited on the bonding surfaces 159 and 259 of the light receiving substrate 100 and the processing substrate 200, the reduction of the bonding area due to the provision of the depressions 175 and 257 is suppressed. Thus, a decrease in bonding strength is prevented.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention. For example, at least one of the two substrates to be bonded to each other is positively formed with a recess having a bottom surface that contacts the other substrate by bonding, or the above-described deformation due to deformation such as distortion generated in the substrate by a circuit formation process or the like. Any substrate having a portion that allows the air in the recess to escape during bonding when the recess is formed is included in the technical scope of the present invention.

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

100, 101 Light receiving substrate, 110, 210 Support substrate, 111 Light receiving circuit, 120 Insulating layer, 220 Bump, 130, 230 Semiconductor well, 132 Photodiode, 140, 240 Gate electrode, 150, 250 Multilayer wiring layer, 152, 252 Interlayer Insulating material, 154, 254 Wiring material, 153 fitting hole, 157, 554 recessed groove, 158, 258, 558 surface, 159, 259 bonding surface, 160, 260 connection pad, 164, 264 barrier layer, 170 light shielding layer, 172 Planarization layer, 174, 182 Organic planarization layer, 175, 257, 551 Concavity, 180 on-chip color filter, 190 on-chip lens, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209 Processing substrate, 211 processing circuit, 25 Mating protrusion, 255, 557 Open hole, 256, 262 Through electrode, 261, 263, 553 Vertical hole, 300, 301, 302, 303, 304, 305, 306, 307 Multilayer substrate, 360, 363 Connection portion, 400 Multilayer semiconductor Device, 500, 501, 502 Substrate, 552 Cavity, 555 Narrow groove, 556 Through hole

Claims (15)

  A substrate having an indented portion that is activated by contacting an activated insulating region on a surface of another substrate and bringing it into contact with the activated insulating region on the surface of another substrate, wherein the insulating region is open toward the surface.   The substrate according to claim 1, wherein the substrate has a conductive region that is exposed toward the surface and is disposed adjacent to the depressed portion.   The substrate according to claim 1, wherein the substrate has a porous layer on the surface.   The part of the depressed portion formed on the substrate includes a portion having a shape complementary to a protruding portion formed on the surface of the other substrate. The substrate described in 1.   The board | substrate as described in any one of Claim 1- Claim 4 in which the said depression part contains the part connected to the peripheral part of the said board | substrate.   The substrate according to any one of claims 1 to 5, wherein the depressed portion has a portion surrounded by a conduction region disposed on the surface of the substrate. Forming a depression in the surface of the insulating region of the substrate that opens toward the surface;
Activating the surface of the insulating region;
A substrate bonding method comprising: bringing the activated insulating region into contact with the activated insulating region on a surface of another substrate to bond the substrate and the other substrate. Forming the depressed portion includes forming a portion communicating with the peripheral edge of the substrate in the depressed portion;
The substrate bonding method according to claim 7, wherein the bonding includes degassing between the substrate and the other substrate through the depressed portion in an environment where the pressure is lower than atmospheric pressure.   The substrate bonding method according to claim 8, wherein the degassing step includes a step of heating at least one of the substrate and the other substrate.   10. The degassing step according to claim 8, wherein the deaeration step includes deaeration between the substrate and the other substrate through the depressed portion prior to bonding of the substrate and the other substrate. Substrate bonding method.   11. The method according to claim 8, wherein the deaeration step includes a step of deaeration between the substrate and the other substrate through the depression while bonding the substrate and the other substrate. The substrate bonding method according to claim 1.   The substrate bonding method according to claim 7, further comprising a step of forming a conductive region that is exposed toward the surface of the substrate and is disposed adjacent to the depressed portion.   The substrate bonding method according to claim 12, further comprising the step of removing at least a part of the barrier layer surrounding the conductive region inside the depressed portion.   The step of forming the depression is formed in a region including an end surface of a conductive region provided in the other substrate when the substrate is bonded to the other substrate. The substrate bonding method according to any one of the above. The step of forming the depression includes
Forming an independent conduction region on the substrate that is not connected to other circuits;
The board | substrate joining method as described in any one of Claim 7-14 including the step which forms the part connected to the peripheral part of the said board | substrate in the said recessed part around the said independent conduction | electrical_connection area | region.

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