Semiconductor device and method for manufacturing the same
11705436 · 2023-07-18
Assignee
Inventors
Cpc classification
H01L25/18
ELECTRICITY
H01L2224/73204
ELECTRICITY
H01L21/78
ELECTRICITY
H01L21/4853
ELECTRICITY
H01L21/30625
ELECTRICITY
H01L2924/00012
ELECTRICITY
H01L2224/131
ELECTRICITY
H01L2225/06506
ELECTRICITY
H01L2224/1012
ELECTRICITY
H01L2224/1012
ELECTRICITY
H01L24/10
ELECTRICITY
H01L2225/06517
ELECTRICITY
H01L21/563
ELECTRICITY
H01L2224/131
ELECTRICITY
H01L2224/2919
ELECTRICITY
H01L2224/32225
ELECTRICITY
H01L2225/0651
ELECTRICITY
H01L2224/2919
ELECTRICITY
H01L2224/83191
ELECTRICITY
H01L23/16
ELECTRICITY
H01L2224/92125
ELECTRICITY
H01L2224/83138
ELECTRICITY
H01L2221/6834
ELECTRICITY
H01L2924/00014
ELECTRICITY
H01L2224/81138
ELECTRICITY
H01L2224/81191
ELECTRICITY
H01L25/50
ELECTRICITY
H01L2924/00014
ELECTRICITY
H01L2224/8349
ELECTRICITY
H01L2224/83192
ELECTRICITY
H01L2924/00012
ELECTRICITY
H01L2224/92247
ELECTRICITY
H01L2225/06575
ELECTRICITY
H01L2224/16225
ELECTRICITY
H01L2225/06582
ELECTRICITY
H01L2224/8385
ELECTRICITY
H01L2225/06562
ELECTRICITY
H01L24/73
ELECTRICITY
H01L2224/8349
ELECTRICITY
International classification
H01L21/48
ELECTRICITY
H01L25/065
ELECTRICITY
H01L21/306
ELECTRICITY
H01L21/78
ELECTRICITY
Abstract
A semiconductor device includes a first semiconductor chip having a first surface and a second surface; a first adhesive layer on the first surface; a second semiconductor chip that includes a third surface and a fourth surface, and a connection bump on the third surface. The connection bump is coupled to the first adhesive layer. The semiconductor device includes a wiring substrate connected to the connection bump. The semiconductor device includes a first resin layer covering the connection bump between the second semiconductor chip and the wiring substrate, and covers one side surface of the second semiconductor chip connecting the third surface and the fourth surface. The first adhesive layer covers an upper portion of the at least one side surface. The first resin layer covers a lower portion of the t least one side surface. The first adhesive layer and the first resin layer contact each other.
Claims
1. A method for manufacturing a semiconductor device, the method comprising: providing a first semiconductor substrate having a first surface and a second surface opposite to each other; forming a first resin layer on the first surface; dicing the first semiconductor substrate into a plurality of first semiconductor chips; providing a second semiconductor substrate having a third surface and a fourth surface opposite to each other; coupling a connection bump on the third surface to a second resin layer; connecting the connection bump to a wiring substrate; and covering the connection bump between a second semiconductor chip and the wiring substrate with the second resin layer, wherein the second resin layer is disposed at a lower portion of a side surface of the second semiconductor chip.
2. The method according to claim 1, further comprising: coupling a first resin tape to the second surface of the first semiconductor substrate; polishing the first surface of the first semiconductor substrate; and forming the first resin layer on the first surface the first semiconductor substrate.
3. The method according to claim 2, further comprising: coupling a second resin tape to the first surface of the first semiconductor substrate via the first resin layer to dice the first semiconductor substrate.
4. The method according to claim 3, further comprising: coupling a third resin tape to the second surface of the first semiconductor chip; adhering the fourth surface of the second semiconductor chip to the first resin layer; applying a material of the second resin layer to the wiring substrate; and connecting the connection bump to the wiring substrate in the second resin layer.
5. The method according to claim 1, wherein the second resin layer covers the second semiconductor chip by extending from the third surface to halfway of the side surface.
6. The method according to claim 1, wherein the first resin layer covers the second semiconductor chip by extending from the fourth surface to halfway of the side surface.
7. The method according to claim 1, wherein the second resin layer includes an underfill or a non-conductive paste (NCP).
8. The method according to claim 1, further comprising: coupling a spacer chip to the first resin layer before coupling the connection bump to the second resin layer.
9. The method according to claim 8, wherein the spacer chip has the same thickness as the second semiconductor chip.
10. The method according to claim 9, further comprising: forming a third resin layer on the spacer chip; and coupling the third resin layer to the wiring substrate.
11. The method according to claim 8, further comprising: covering the spacer chip between the first semiconductor chip and the wiring substrate with the second resin layer.
12. A method for manufacturing a semiconductor device, the method comprising: providing a first semiconductor substrate having a first surface and a second surface opposite to each other; forming a first resin layer on the first surface; dicing the first semiconductor substrate into a plurality of first semiconductor chips; providing a second semiconductor substrate having a third surface and a fourth surface opposite to each other; coupling a spacer chip to the first resin layer; coupling a connection bump on the third surface to a second resin layer; connecting the connection bump to a wiring substrate; and covering the connection bump between a second semiconductor chip and the wiring substrate with the second resin layer, wherein the second resin layer is disposed at a lower portion of a side surface of the second semiconductor chip.
13. The method according to claim 12, wherein the spacer chip has the same thickness as the second semiconductor chip.
14. The method according to claim 13, further comprising: forming a third resin layer on the spacer chip; and coupling the third resin layer to the wiring substrate.
15. The method according to claim 12, further comprising: covering the spacer chip between the first semiconductor chip and the wiring substrate with the second resin layer.
Description
DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION
(28) Embodiments provide a semiconductor device capable of preventing a resin from adhering to a mounting tool and surely connecting a semiconductor chip to a substrate, and a method for manufacturing the same.
(29) In general, according to one embodiment, a semiconductor device includes a first semiconductor chip having a first surface and a second surface opposite to the first surface. The semiconductor device includes a first adhesive layer provided on the first surface. The semiconductor device includes a second semiconductor chip including: a third surface and a fourth surface opposite to the third surface; and a connection bump on the third surface. The connection bump is coupled to the first adhesive layer. The semiconductor device includes a wiring substrate connected to the connection bump. The semiconductor device includes a first resin layer that covers the connection bump between the second semiconductor chip and the wiring substrate, and further covers at least one side surface of the second semiconductor chip connecting the third surface and the fourth surface. The first adhesive layer covers an upper portion of the at least one side surface. The first resin layer covers a lower portion of the t least one side surface. The first adhesive layer and the first resin layer contact each other.
(30) Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings. The embodiments do not limit the present disclosure. In the following embodiment, a vertical direction of a substrate indicates a relative direction when a surface on which a semiconductor chip is mounted is defined as “UP”, and may be different from a vertical direction according to acceleration of gravity. The drawings are schematic or conceptual, and a proportion of each portion is not necessarily the same as that of the actual one. In the specification and the drawings, the same elements as those described above with reference to the already illustrated drawings will be denoted by the same reference signs, and detailed description thereof will be appropriately omitted.
First Embodiment
(31)
(32) The semiconductor device 1 is, for example, a package of a NAND type flash memory. The semiconductor chip 10 is, for example, a memory chip of the NAND type flash memory. The semiconductor chip 10 includes a rear surface 10A, a front surface 10B on the opposite side of the rear surface 10A, and a side surface 10C between the rear surface 10A and the front surface 10B. A semiconductor element 11 is provided on the front surface 10B of the semiconductor chip 10 and is covered with a protective film such as polyimide. The semiconductor element 11 may be, for example, a memory cell array or a peripheral circuit (a complementary metal oxide semiconductor (CMOS) circuit). The memory cell array may be a three-dimensional memory cell array in which a plurality of memory cells are arranged three-dimensionally. A pad 12 electrically connected to anyone of the semiconductor elements 11 is provided on the front surface 10B.
(33) The adhesive layer 40 is provided on the rear surface 10A of the semiconductor chip 10. The adhesive layer 40 is, for example, a die attachment film (DAF), and adheres between the semiconductor chip 10 and the semiconductor chip 20.
(34) The semiconductor chip 20 is, for example, a controller chip that controls a memory chip. The semiconductor chip 20 includes a rear surface 20A that faces the wiring substrate, a front surface 20B on the opposite side of the rear surface 20A, and a side surface 20C between the rear surface 20A and the front surface 20B. A semiconductor element 21 is provided on the rear surface 20A of the semiconductor chip 20, and is covered with a protective film such as polyimide. The semiconductor element 21 may be, for example, the CMOS circuit forming a controller. A bump 25 electrically connected to the semiconductor element 21 is provided on the rear surface 20A. For example, a low resistance metal material such as solder is used for the bump 25.
(35) The front surface 20B of the semiconductor chip 20 adheres to the rear surface 10A of the semiconductor chip 10 via the adhesive layer 40.
(36) Although not illustrated, the wiring substrate 30 may be, for example, a printed substrate and an interposer including a plurality of wiring layers and a plurality of insulating layers. For example, a low resistance metal such as copper is used for the wiring layer. For example, an insulating material such as glass epoxy resin is used for the insulating layer. A pad 32 electrically connected to any one of the wiring layers is provided on the front surface of the wiring substrate 30. The metal bump 25 of the semiconductor chip 20 is connected to the wiring layer via a pad (not illustrated) on the front surface of the wiring substrate 30. Accordingly, the semiconductor chips 10 and 20 can be controlled via the wiring layer of the wiring substrate 30.
(37) The resin layer 50 is, for example, a resin such as an underfill or a non-conductive paste (NCP). The resin layer 50 covers the bump 25 provided between the semiconductor chip 20 and the wiring substrate 30, and protects the connection between the bump 25 and the wiring substrate 30. When the bump 25 of the semiconductor chip 20 is connected to the wiring substrate 30, the resin layer 50 is supplied as a liquid. Therefore, the resin layer 50 fills a space between the semiconductor chip 20 and the wiring substrate 30, creeps up along the side surface 20C of the semiconductor chip 20, and covers at least a lower portion of the side surface 20C. A configuration of the resin layer 50 will be illustrated later with reference to
(38) Another semiconductor chip 15 maybe stacked on the front surface 10B of the semiconductor chip 10. The semiconductor chip 15 adheres to the front surface 10B of the semiconductor chip 10 via the adhesive layer 45. The semiconductor chip 15 may be a memory chip having the same configuration as that of the semiconductor chip 10 or a semiconductor chip having another configuration. In the drawing, in addition to the semiconductor chip 20 serving as a controller chip, two semiconductor chips 10 and 15 are stacked. However, the number of stacked semiconductor chips may be three or more. A plurality of controller chips may be disposed in parallel to the surface of the wiring substrate 30.
(39) The bonding wire 60 connects the pads 12, 16, and 32 of the semiconductor chips 10, 15, and 20.
(40) The sealing resin 70 embeds and seals the semiconductor chips 10, 15, and 20, the resin layer 50, and the bonding wire 60. Accordingly, the semiconductor device 1 is configured with a plurality of the semiconductor chips 10, 15, and 20 as one semiconductor package.
(41)
(42) On the other hand, as described above, the resin layer 50 creeps up from the rear surface 20A of the semiconductor chip 20 along the side surface 20C, and covers the lower portion of the side surface 20C. That is, the resin layer 50 covers the semiconductor chip 20 from the rear surface 20A thereof to the lower portion of the side surface 20C thereof halfway.
(43) The adhesive layer 40 and the resin layer 50 contact each other on the side surface 20C, and the sealing resin 70 does not enter therebetween. Therefore, the side surface 20C is covered with the adhesive layer 40 and the resin layer 50, and does not contact the sealing resin 70. The sealing resin 70 is separated from the side surface 20C of the semiconductor chip 20 by the adhesive layer 40 and the resin layer 50.
(44) The resin layer 50 includes a recess RC at a boundary portion between the resin layer 50 and the side surface 20C of the semiconductor chip 20. The adhesive layer 40 includes a protrusion portion PR corresponding to the recess RC at a boundary portion between the adhesive layer 40 and the side surface 20C. In this manner, the recess RC and the protrusion portion PR are formed because the resin layer 50 creeps up along the side surface 20C of the semiconductor chip 20 after the semiconductor chip 10 adheres to the semiconductor chip 20 with the adhesive layer 40. That is, the semiconductor chip 10 adheres to the semiconductor chip 20 with the adhesive layer 40, the bump 25 of the semiconductor chip 20 is connected to the wiring substrate 30, after which the resin layer 50 is supplied between the semiconductor chip 20 and the wiring substrate 30. Alternatively, the semiconductor chip 10 adheres to the semiconductor chip 20 with the adhesive layer 40, and the resin layer 50 is applied to the wiring substrate 30, after which the bump 25 of the semiconductor chip 20 is put in the resin layer 50 and connected to the wiring substrate 30. The recess RC and the protrusion portion PR are formed in the order of the above-described manufacturing process of the semiconductor device 1. Therefore, the recess RC and the protrusion portion PR may be formed not a part of the outer circumference of the semiconductor chip 20 but over the entire circumference.
(45) The semiconductor chip 20 adheres to the adhesive layer 40 before contacting the resin layer 50. Therefore, the adhesive layer 40 covers the whole front surface 20B of the semiconductor chip 20. On the other hand, the resin layer 50 does not contact the front surface 20B of the semiconductor chip 20. That is, the resin layer 50 does not enter between the front surface 20B of the semiconductor chip 20 and the adhesive layer 40, and is not interposed therebetween.
(46)
(47) Next, a method for manufacturing the semiconductor device 1 according to the embodiment will be described.
(48)
(49) First, a grind resin tape TP1 is stuck to the front surface 10B of the semiconductor chip 10. Next, as illustrate in
(50) Next, the adhesive layer 40 adheres to the rear surface 10A of the semiconductor wafer 10W. Next, as illustrated in
(51) Next, as illustrated in
(52) Next, as illustrated in
(53) Next, as illustrated in
(54) Next, as illustrated in
(55) Next, the semiconductor chips 10 and 20 in
(56) It is preferred that a thickness of the semiconductor chip 20 is, for example, 20 μm to 70 μm. When the thickness of the semiconductor chip 20 is less than 20 μm, an operation of the semiconductor chip becomes difficult due to an influence of a depletion layer of a transistor formed in the semiconductor chip 20. On the other hand, when the thickness of the semiconductor chip 20 exceeds 70 μm, the resin layer 50 may not reach the adhesive layer 40. In this case, the side surface 20C of the semiconductor chip 20 may not be covered with the resin layer 50 and may not be protected. In this case, the sealing resin 70 may contact the side surface 20C of the semiconductor chip 20.
(57) The mounting tool MT stacks another semiconductor chip 15 on the semiconductor chip 10. The semiconductor chip 15 adheres to the front surface 10B of the semiconductor chip 10 by the adhesive layer 45.
(58) Next, the bonding wire 60 is used to connect the semiconductor chips 10, 15 and 20, and the pad of the wiring substrate 30. After that, in a molding step, the semiconductor chips 10, 20, and 15 on the wiring substrate 30 are resin-sealed with the sealing resin 70. Accordingly, the package of the semiconductor device 1 illustrated in
(59) As described above, according to the embodiment, after the semiconductor chip 20 adheres to the semiconductor chip 10, the semiconductor chip 20 is flip-chip connected to the wiring substrate 30 together with the semiconductor chip 10.
(60) When only the semiconductor chip 20 is flip-chip connected to the wiring substrate 30, the mounting tool MT sucks the semiconductor chip 20, and connects the bump 25 to the wiring substrate 30 while the semiconductor chip 20 contacts the resin layer 50 on the wiring substrate 30. In this case, the resin layer 50 creeps up along the side surface 20C of the semiconductor chip 20. It is conceivable to protect a front surface of the mounting tool with a film (not illustrated) so that the underfill does not adhere to the mounting tool MT. However, in this case, as described above, it is required to form the suction hole in the film for each semiconductor chip 20, thereby causing the deterioration in throughput. Since the film is exchanged for each mounting process, the cost of the film is high. The resin layer 50 also goes around on the front surface 20B of the semiconductor chip 20, and the resin layer 50 enters between the semiconductor chip 20 and the adhesive layer 40. In this case, the semiconductor chip 20 and the adhesive layer 40 may be peeled off during a moisture absorption reflow of a reliability test.
(61) On the other hand, in the method for manufacturing according to the embodiment, after the semiconductor chip 20 adheres to the semiconductor chip 10, the semiconductor chip 20 is flip-chip connected to the wiring substrate 30 together with the semiconductor chip 10. As described above, the order of the stacking step of the semiconductor chips 10 and 20 and the flip-chip connection step of the semiconductor chip 20 is reversed. Accordingly, even though the resin layer 50 creeps up along the side surface 20C of the semiconductor chip 20, the semiconductor chip 10 prevents the resin layer 50 from reaching the mounting tool MT. Therefore, the embodiment can shorten the throughput and reduce the manufacturing cost without requiring the film for covering the mounting tool MT.
(62) Since the stacking step of the semiconductor chips 10 and 20 is performed before the flip-chip connection step of the semiconductor chips 20, the resin layer 50 does not go around the front surface 20B of the semiconductor chip 20. That is, even though the resin layer 50 creeps up the side surface 20C of the semiconductor chip 20, the adhesive layer 40 already adheres to the front surface 20B of the semiconductor chip 20, such that the resin layer 50 does not contact the front surface 20B of the semiconductor chip 20. On the other hand, as illustrated in
(63) It is desirable that the semiconductor chip 10 is larger than the semiconductor chip 20, and the outer edge of the semiconductor chip 10 is outside (offset from) the outer edge of the semiconductor chip 20, when viewed from above the front surface 10B of the semiconductor chip 10. This more effectively prevents the resin layer 50 from reaching the mounting tool MT.
(64) However, it is not necessarily required that the semiconductor chip 10 should be larger than the semiconductor chip 20. Even though a size of the semiconductor chip 10 is equal to or smaller than a size of the semiconductor chip 20, the semiconductor chip 10 can cause the mounting tool MT and the semiconductor chip 20 to be separated from each other by the thickness thereof. Therefore, the effect of the embodiment can be obtained only by reversing the order of the stacking step of the semiconductor chips 10 and 20 and the flip-chip connection step of the semiconductor chip 20.
(65) The resin layer 50 fills a periphery of the bump 25 provided between the rear surface 20A of the semiconductor chip 20 and the wiring substrate 30. As illustrated in
(66) The semiconductor chip 20 is flip-chip connected to the wiring substrate 30 in a state of adhering to the semiconductor chip 10. Therefore, even though the thickness of the semiconductor chip 20 is as thin as 70 μm or less, the warpage of the semiconductor chip 20 is corrected by the semiconductor chip 10. As a result, the bump 25 can be surely connected to the wiring substrate 30 in the flip-chip connection.
Second Embodiment
(67) In the first embodiment, as illustrated in
(68) However, for example, when the alignment is performed by using an infrared ray, the alignment can be performed from the rear surface 10A of the semiconductor wafer 10W. In this case, it is not required to move the semiconductor wafer 10W from the resin tape TP1 to the resin tape TP2. Therefore, in the second embodiment, the semiconductor wafer 10W is polished, diced, and stuck to the semiconductor chip 20 by commonly using the resin tape TP1.
(69)
(70) As illustrated in
(71) According to the second embodiment, since it is not required to change the resin tape frequently, throughput can be further shortened and manufacturing cost can be further reduced.
(72) A configuration of the second embodiment maybe the same as that of the first embodiment. Therefore, the second embodiment can also obtain the effect of the first embodiment.
Third Embodiment
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(74)
(75) Although not illustrated in
(76) Next, as illustrated in
(77) Thereafter, by going through the steps illustrated in
(78) In the third embodiment, the adhesive layer 40 does not cover the whole rear surface 10A of the semiconductor chip 10. However, the adhesive layer 40 fills a whole space between the semiconductor chip 10 and the semiconductor chip 20. Therefore, also in the third embodiment, the resin layer 50 does not contact the front surface 20B of the semiconductor chip 20. Accordingly, the third embodiment can obtain the effect of the first embodiment. In the third embodiment, in the same manner as that of the second embodiment, since it is not required to change the resin tape frequently, the same effect as that of the second embodiment can be obtained.
Fourth Embodiment
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(80) In the step illustrated in
(81) When the resin layer 50 is solidified, the semiconductor chip 10 can be supported. Accordingly, in the fourth embodiment, a spacer chip which will be described later is not required. Other configurations of the fourth embodiment may be the same as those of the first embodiment. As a result, the fourth embodiment can obtain the same effect as that of the first embodiment.
Fifth Embodiment
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(83) The rear surface of the spacer chip 80 adheres to the front surface of the wiring substrate 30 by an adhesive layer 47. The front surface of the spacer chip 80 adheres to the adhesive layer 40 on the rear surface 10A of the semiconductor chip 10. The sealing resin 70 is embedded around a periphery of the spacer chip 80 between the semiconductor chip 10 and the wiring substrate 30.
(84) The spacer chip 80 has almost the same thickness as the semiconductor chip 20. The spacer chip 80 may be formed of the same material as the substrate of the semiconductor chip (for example, a silicon substrate). Accordingly, the spacer chip 80 can support the semiconductor chip 10 around the periphery of the semiconductor chip 20, correct the warpage of the semiconductor chip 10, and flatten the semiconductor chip 10. Other configurations of the fifth embodiment may be the same as those of the first embodiment, and can further obtain the same effect as that of the first embodiment.
(85)
(86) Thereafter, the semiconductor device 1 illustrated in
(87) According to the fifth embodiment, the spacer chip 80 can support the semiconductor chip 10 around the periphery of the semiconductor chip 20, correct the warpage of the semiconductor chip 10, and flatten the semiconductor chip 10.
Modification
(88)
Sixth Embodiment
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(90) The resin layer 50 is entirely filled between the rear surface 10A of the semiconductor chip 10 and the front surface of the wiring substrate 30. Accordingly, the peripheries of the semiconductor chip 20 and the spacer chip 80 (the side surfaces thereof) are covered and protected by the resin layer 50.
(91) Other configurations of the sixth embodiment may be the same as those of the fourth or fifth embodiment. Therefore, the sixth embodiment can obtain the effect of the fourth and fifth embodiments.
Seventh Embodiment
(92)
(93) Other configurations of the seventh embodiment may be the same as the corresponding configurations of the third or fifth embodiment. Therefore, the seventh embodiment can obtain the effect of the third and fifth embodiments.
(94) In the seventh embodiment, the spacer chip 80 does not adhere to the semiconductor chip 10 by the adhesive layer 40. Therefore, in the method for manufacturing according to the seventh embodiment, the spacer chip 80 of the seventh embodiment may adhere to the wiring substrate 30 with the adhesive layer 47 before the semiconductor chip 20 is flip-chip connected to the wiring substrate 30 as shown in the modification of the fifth embodiment. Accordingly, the spacer chip 80 is fixed to a predetermined location of the wiring substrate 30 by the adhesive layer 47.
Eighth Embodiment
(95)
(96) Other configurations of the eighth embodiment may be the same as the corresponding configurations of the fifth embodiment. Therefore, the eighth embodiment can obtain the effect of the fifth embodiment.
(97) In the eighth embodiment, since the adhesive layer 47 is not provided, in the method for manufacturing according to the eighth embodiment, the spacer chip 80 adheres to the semiconductor chip 10 via the adhesive layer 40 in the same manner as that of the fifth embodiment. As a result, the spacer chip 80 is disposed at a predetermined location of the wiring substrate 30 when the semiconductor chip 20 is flip-chip connected to the wiring substrate 30.
Ninth Embodiment
(98)
(99) In the method for manufacturing according to the ninth embodiment, the adhesive layer 40 is provided in the spacer chip 80 before the semiconductor chip 20 is flip-chip connected to the wiring substrate 30, and the spacer chip 80 adheres to the semiconductor chip 10. Accordingly, the spacer chip 80 is disposed at a predetermined location of the wiring substrate 30 when the semiconductor chip 20 is flip-chip connected to the wiring substrate 30.
Tenth Embodiment
(100)
(101) Other configurations of the tenth embodiment may be the same as the corresponding configurations of the fourth and ninth embodiments. Therefore, the tenth embodiment can obtain the effect of the fourth and ninth embodiments.
Eleventh Embodiment
(102)
(103) Other configurations of the eleventh embodiment may be the same as the corresponding configurations of the fourth and seventh embodiment. Therefore, the eleventh embodiment can obtain the effect of the fourth and seventh embodiments.
(104) While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosure. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the disclosure. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosure.