The disclosure of Japanese Patent Application No. 2011-55454 filed on Mar. 14, 2011 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
The present invention relates to a semiconductor integrated circuit device and a method of manufacturing the same, and particularly relates to a semiconductor integrated circuit device, in which a bump electrode as an external connection terminal or a bonding wiring is connected to a first end of a rewiring that is formed over the device surface of a semiconductor chip, and a technology that is effective when applied to an electronic system, such as a mobile electronic device, having the semiconductor integrated circuit device mounted on.
For a semiconductor integrated circuit device, a multilayer wiring is formed by metal films including copper (Cu) or aluminum (Al) alloy as a main component at an upper portion of a semiconductor substrate formed with semiconductor elements, such as, complementary metal insulator semiconductor (CMIS) transistors, and a final passivation film (surface protection film) is formed at an upper portion of the multilayer wiring.
As disclosed in Japanese Patent Laid-Open No. 2003-234348 (Patent Document 1) and Japanese Patent Laid-Open No. 2005-026301 (Patent Document 2), technology is known in which a rewiring containing Cu as a main component is formed over a final passivation film, and an electrode pad formed on an uppermost-layer wiring under the final passivation film and the rewiring are electrically connected.
Patent Document 2 discloses a semiconductor device in which a solder bump as an external connection terminal is connected to the surface of a land section, which is a first end of a rewiring. For this semiconductor device, after a rewiring is formed, an underlayer including a conductive material is formed at a lower portion of the rewiring to have a smaller area than that of the land section of the rewiring by over-etching of the conductive material.
In a forming method by over-etching of a conductive material, if an underlayer is thickened to reduce the stress applied to a solder bump, the amount of over-etching of the underlayer also becomes large, which makes it difficult to control the wiring dimension and control the wiring resistance of the underlayer, resulting in a drop in the properties of a semiconductor device. Particularly, if the wiring length of the rewiring becomes large by miniaturization, high integration, or multiple pins, drop in the properties of the semiconductor device becomes a problem.
Further, for a semiconductor integrated circuit device having a rewiring, a structure is employed where a bump electrode (solder bump) as an external connection terminal is connected to a first end (land section) of a rewiring formed over a device surface of a semiconductor chip, and the semiconductor chip is mounted on a wiring substrate or the like via this bump electrode.
The inventors mounted a semiconductor integrated circuit device with such a structure on a mobile electronic device, such as a mobile phone and a laptop, and made a vibration test and a drop shock test. As a result, the inventors discovered a phenomenon that a portion of a bump electrode connecting a semiconductor chip and a wiring substrate lost connection.
The inventors sought a cause of the disconnection, and found that the disconnection was mainly caused by that the end portion of a bump electrode peeled off from the surface of a rewiring due to vibration or drop shock and this peeling-off developed toward the center of the bump electrode.
By filling under-fill resin into the gap between the semiconductor chip and the wiring substrate, the inventors devised a solution to reinforce the adhesive force between the semiconductor chip and the wiring substrate. As a result, disconnection of a bump electrode during the vibration test and drop shock test was successfully reduced.
The above solution by filling under-fill resin into the gap between a semiconductor chip and a wiring substrate requires a manufacturing line dedicated for applying under-fill resin, which causes a problem of significant increase in the cost of a semiconductor integrated circuit device. Further, in filling under-fill resin into the gap between a bump electrode and a wiring substrate, there is also a problem of making it difficult to remove a semiconductor chip from a wiring substrate when a defect of the semiconductor chip has occurred after its mounting.
The present invention has been made in view of the above circumstances and provides a technology that improves the properties of a semiconductor integrated circuit device having a rewiring structure.
The present invention further provides a technology that improves the adhesive strength between a rewiring and an external connection terminal, for a semiconductor integrated circuit device having a structure where an external connection terminal is connected to a first end (land section) of a rewiring formed over the device surface of a semiconductor chip.
The present invention still further provides a technology that reduces the wiring resistance of a rewiring without reducing the adhesive strength between the rewiring and an external connection terminal.
The other purposes and the new feature of the present invention will become clear from the description of the present specification and the accompanying drawings.
The following explains briefly the outline of a typical invention among the inventions disclosed in the present application.
(1) A semiconductor integrated circuit device that is an embodiment of the present invention includes (a) a semiconductor substrate having a device surface; (b) a plurality of semiconductor elements formed on the device surface and a multi-layer wiring that connects between the semiconductor elements; (c) a protection film that covers, the device surface and an upper portion of an uppermost layer wiring of the multi-layer wiring; (d) a first electrode pad that is formed by a portion of the uppermost layer wiring and is exposed from a pad opening formed in the protection film; (e) a rewiring formed at the upper portion of the protection film and having the first end electrically connected to the first electrode pad through the pad opening and the second end forming a land section formation region; and (f) a first insulation film that is formed to cover the rewiring and has a first opening at the upper portion of the land section formation region, the rewiring includes a first metal film that includes a metal film including copper as a main component, and a second metal film formed at the upper portion of the first metal film, the land section formation region is formed such that an area of the second metal film is larger than that of the first metal film, and the first insulation film is formed directly under the second metal film at an end portion of a land, section to which a bump electrode is connected in the land section formation region. (2) The rewiring has a portion where the second metal film is not formed over the first metal film extending from the first electrode pad to the land section formation region. (3) The second metal film has a film thickness larger than that of the first metal film with the second metal film not formed at the upper portion thereof. (4) A rewiring not connected to the bump electrode is formed by the first metal film with the second metal film not formed at the upper portion. (5) A dummy wiring is formed by the first metal film with the second metal film not formed at the upper portion. (6) At least one of a resistance element, a capacitor, and a capacitance element is formed by the first metal film with the second metal film not formed at the upper portion.
The following explains briefly the effect acquired by the typical invention among the inventions disclosed in the present application.
The properties of a semiconductor integrated circuit device having a rewiring are improved.
For a semiconductor integrated circuit device having a structure where an external connection terminal is connected to a first end (land section) of a rewiring, the adhesive strength between the rewiring and the external connection terminal is improved.
For a semiconductor integrated circuit device having a structure where an external connection terminal is connected to a first end (land section) of a rewiring, the wiring resistance of the rewiring can be reduced without reduction in the adhesive strength between the rewiring and the external connection terminal.
Embodiments of the present invention will be described below in detail, based on the drawings. In all the drawings for explaining embodiments, the same symbol is attached to members having the same function, and the repeated explanation thereof is omitted. In the embodiments, explanation of the same or a similar part is not repeated unless necessary. In the drawings for illustrating the embodiments, in order to make a drawing intelligible, hatching may be attached even if it is a plan view, and hatching may be omitted even if it is a cross-sectional view.
A semiconductor integrated circuit device (semiconductor device) in the present embodiment includes an integrated circuit that has a plurality of semiconductor elements formed on the device surface of a semiconductor chip and wiring of plural layers (multi-layer wiring) for connection between the semiconductor elements. A semiconductor integrated circuit device is mounted on a mobile electronic device, such as, a mobile phone or a laptop. A semiconductor integrated circuit device to be mounted on a mobile electronic device may be a CPU, a microprocessor, a controller, an analog circuit, a logic circuit such as a circuit for high-frequency communication, a storage circuit such as a memory, or a logic circuit mounting a storage circuit. Further, this semiconductor integrated circuit device may be one applied to an IC for a hard disk drive (HDD).
Among the circuits of the semiconductor integrated circuit device, the CMIS-logic circuit includes a CMIS transistor with an operation voltage of 1 to 3 V, and the I/O circuit and the memory circuit includes a CMIS transistor with an operation voltage of 1 to 3 V or 5 to 8 V. The CMIS transistor with the operation voltage of 1 to 3 V includes a first n-channel metal insulator semiconductor field effect transistor (MISFET) having a first gate insulation film, and a first p-channel MISFET having a first insulation film. The CMIS transistor with the operation voltage of 5 to 8 V includes a second n-channel MISFET having a second gate insulation film, and a second p-channel MISFET having a second gate insulation film. The film thickness of the second gate insulation film is made larger than that of the first gate insulation film. An MISFET will be referred to as an MIS transistor in the description below.
The analog circuit includes the CMIS transistor (or bipolar transistor) with an operation voltage 5 to 8 V, a resistance element, and a capacitance element. A power MIS circuit includes the CMIS transistor with an operation voltage of 5 to 8 V and a high-voltage MIS transistor (high-voltage resistant element) with an operation voltage of 20 to 100 V.
The high-voltage MIS transistor is configured with, for example, a third n-channel MISFET having a third gate insulation film, a third p-channel MISFET having a third gate insulation film, or the both. If a voltage of 20 to 100 V is applied between the gate electrode and a drain region or between the gate electrode and a source region, the film thickness of the third gate insulation film is made larger than that of the second gate insulation film.
As shown in
Over the p-type well 2, an n-channel MIS transistor (Qn) is formed. The n-channel MIS transistor (Qn) includes a source region 4s and a drain region 4d formed in the p-type well 2 that is an active region defined by the element isolation groove 3, and a gate electrode 4g formed over the p-type well 2 via a gate oxide film 4i. For the real semiconductor substrate 1P, further formed are various semiconductor elements, such as a n-type well, a p-channel MIS transistor, a resistance element, and a capacitance element, but
At the upper portion of the n-channel MIS transistor (Qn), wirings of metal films are formed to connect between semiconductor elements. In general, wirings connecting between semiconductor elements have a multi-layer wiring structure of approximately 3 to 10 layers. As a multi-layer wiring,
Further, between the n-channel MIS transistor (Qn) and the first layer wiring 5a, between the first layer wiring 5a and the second layer wiring 5b, and between the second layer wiring 5b and the third layer wiring 5c, formed are inter-layer insulation films 6a, 6b, and 6c made of a silicon oxide film, a low dielectric film (such as SiCO film, SiCON film, and SiCO film) with an dielectric constant lower than that of a silicon oxide film, or the like.
The inter-layer insulation film 6a of the first layer is formed over the semiconductor substrate 1P to cover semiconductor elements, and the first layer wiring 5a is formed over the inter-layer insulation film 6a. The first layer wiring 5a is electrically connected, through a plug 7a formed through the inter-layer insulation film 6a, with semiconductor elements, such as, the source region 4s, the drain region 4d, and the gate electrode 4g of the n-channel MIS transistor (Qn).
The second layer wiring 5b formed over the inter-layer insulation film 6b of the second layer is electrically connected to the first layer wiring 5a through a plug 7b formed in the inter-layer insulation film 6b. Further, the third layer wiring 5c formed over the inter-layer insulation film 6c of the third layer is electrically connected to the second layer wiring 5b through a plug 7c formed in the inter-layer insulation film 6c. The plugs 7a, 7b, and 7c are formed by a metal film, such as a W (tungsten) film.
The multi-layer wiring (three layer wiring) is formed by metal films and plugs. In forming the multi-layer wiring with metal films containing copper (Cu) as a main component by using a chemical mechanical polishing (CMP) method, the wirings and the plugs may be integrally formed by a dual damascene method. Further, in this case, the inter-layer insulation films 6a, 6b, and 6c may be formed by, in place of the silicon oxide film, a single-layer film or a laminated layer film of low dielectric films with a lower dielectric constant than that of a silicon oxide film, such as a silicon oxide film including carbon (SiOC film), a silicon oxide film including nitrogen and carbon (SiCON film), or a silicon oxide film including fluorine (SiOF film).
At the upper portion of the third layer wiring 5c, which is the uppermost layer wiring of the multi-layer wiring (three layer wiring), formed is as a final passivation film a surface protection film 8 that is a single layer film of a silicon oxide film or a silicon nitride film, or a two layer film with lamination of these insulation films. Further, a portion of the surface protection film 8 is formed with a pad opening 9, and the uppermost layer wiring (the third layer wiring 5c) exposed at the bottom of the pad opening 9 forms a pad (first electrode pad) 10, which is an electrode pad. Pads 10 are arrayed in a row along each side of the semiconductor chip 1A, as shown in
A polyimide resin film 12, which is an insulation film, is formed at the upper portion of the surface protection film 8. The polyimide resin film 12 above the pad opening 9 is provided with an opening 11. Further, at the upper portion of the polyimide resin film 12, a rewiring 20 is formed which is electrically connected to the pad 10 through the opening 11 of the polyimide resin film 12 and the pad opening 9 of the surface protection film 8. The polyimide resin film 12 is formed thicker than the surface protection film 8.
As shown in
In the five layer metal film forming the rewiring 20, the Cu film 15, which is a conductive film, has the lowest electrical resistance and has a larger film thickness than other conductive film. Accordingly, the electrical resistance of the rewiring 20 is about equal to that of this Cu film 15. The electrical resistance of the rewiring 20 is about equal to that of the conductive material (Cu) having a lower electrical resistance compared with the lower layer wiring (first layer wiring 5a, second layer wiring 5b, and third layer wiring 5c). The thickness of the rewiring 20 is larger than that of the multi-layer wiring of the lower layer (first layer wiring 5a, second layer wiring 5b, and third layer wiring 5c). The wiring resistance of the rewiring 20 is lower than that of the multi-layer wiring of the lower layer (first layer wiring 5a, second layer wiring 5b, and third layer wiring 5c).
As shown in
As will be explained in the description of a manufacturing method using later-described
Further, as will be described later, by forming the thickness of the first layer metal film 20′ to be larger than the thickness of the second layer metal film (second Ni film 17), the wiring resistance of the rewiring 20 can be reduced without reducing the adhesive strength between the rewiring 20 and the solder bump 21. The portion (the wiring section formed by the first layer metal film 20′) of the rewiring 20 other than the land section formation region is formed with a structure where the second layer metal film (second Ni film 17) is not formed at the upper portion of the first layer metal film 20′. In the rewiring 20 extending from the pad (first electrode pad) 10 to the land section 20A, in the region other than the land section 20A, the second layer metal film (second Ni film 17) is not formed at the upper portion of the first layer metal film 20′.
Further, the first mask and the second mask which has a plane pattern different from that of the first mask are used to form the rewiring 20. It is possible to improve the controllability of the dimensions of the rewiring 20, the controllability of the wiring resistance, and the properties of the semiconductor integrated circuit device. As shown in
Further, as the second layer metal film (second Ni film 17) is required to be formed only in the land section formation region, the degree of freedom of designing a wiring section is improved, and miniaturization, high integration, and multiple pins can be accelerated, which improves the properties of a semiconductor integrated circuit device. Still further, as described later, the film thickness of the polyimide resin film 22, which is an insulation film at the upper portion of the wiring section, is larger at a portion as an insulation film at the upper portion of the wiring section than at a portion as an insulation film at the upper portion of the second layer metal film. Thus, it is possible to improve the reliability of the semiconductor integrated circuit device and the properties of the semiconductor device. Further, when the efficiency in dicing a wafer, damage caused through the dicing, and the like are taken into account, even if the thickness of the polyimide resin film 22 is made small, the film thickness of the polyimide resin film 22, which is an insulation film at the upper portion of the wiring section, is large, and the properties of the semiconductor integrated circuit device can be accordingly improved.
Parts of the plural solder bumps 21 formed on the device surface of the semiconductor chip 1A shown in
Further, as shown in
As shown in
The dimensions of the portions of the land section 20A of the rewiring 20, which corresponds to the land section formation region in
Symbol LA in
The land section 20A of the rewiring 20 is arranged in the following manner. Of the five-layer metal film (barrier metal film 13, seed film 14, Cu film 15, first Ni film 16, and second Ni film 17) forming the rewiring 20, the area of the second Ni film 17 (second layer metal film), which is the uppermost-layer metal film, is larger than the areas of the other metal films (barrier metal film 13, seed film 14, Cu film 15, and first Ni film 16), and the solder bump 21 is connected to the surface of the second Ni film 17. At the end portion of the solder bump 21, the rewiring 20 is formed only by a single-layer metal film (second layer metal film; second Ni film 17), and the polyimide resin film 22, which includes an insulation film of a material softer than a metal film, is formed directly under the second Ni film 17.
In such a manner, when a stress is applied from outside the semiconductor chip 1A to the end portion of the solder bump 21, which forms the external connection terminal, this stress is reduced and absorbed by the polyimide resin film 22, which is an insulation film formed below the end portion of the solder bump 21. Thus, the problem that the end portion of the solder bump 21 peels off from the surface of the land section 20A is controlled. Accordingly, the adhesive strength between the solder bump 21 and the land section 20A is improved.
Further, the film thickness of the first layer metal film 20′ (barrier metal film 13, seed film 14, Cu film 15, and first Ni film 16) is formed larger than the film thickness of the second layer metal film (second Ni film 17) so that the wiring resistance of the rewiring 20 can be reduced without reducing the adhesive strength between the rewiring 20 and the solder bump 21. Still further, the polyimide resin film 22, as an insulation film at the upper portion of the wiring section, has a film thickness larger than that of the polyimide resin film 22, as an insulation film at the upper portion of the second layer metal film (second Ni film 17). Accordingly, it is possible to improve the reliability of the semiconductor integrated circuit device and the properties of the semiconductor integrated circuit device.
A method of manufacturing a semiconductor integrated circuit device (semiconductor device) in accordance with the embodiment will be described below.
Then, as shown in
Then, as shown in
Then, as shown in
Then, as shown in
Then, as shown in
Next, as shown in
As shown in
The five layer metal film (barrier metal film 13, seed film 14, Cu film 15, first Ni film 16, and second Ni film 17) in the region of the opening 32 (the land section formation region) becomes the land section formation region with a structure where the second layer Ni film 17 is formed at the upper portion of the first layer metal film 20′. The four layer metal film (barrier metal film 13, seed film 14, Cu film 15, and first Ni film 16) in the region of the opening 30 other than the land section formation region becomes the portion (wiring section) of the rewiring 20 other than the land section formation region, and forms the first layer metal film 20′.
Then, as shown in
Using the photoresist film pattern 31 which is the first mask and the opening 30, the copper(Cu) film 15 and the first Ni film 16 which are conductive films are formed to form the first layer metal film (first metal film) 20′. Further, using the photoresist film pattern 33 which is the second mask with a plane pattern different from that of the first mask and the opening 32, the second Ni film 17 which is a conductive film is formed to form the second layer metal film (second metal film).
The land section formation region of the rewiring 20 is formed with a structure where the second layer metal film (second Ni film 17) is formed at the upper portion of the first layer metal film 20′, and the portion (wiring section) other than the land section formation region of the rewiring 20 is arranged with a structure where the second layer metal film (second Ni film 17) is not formed at the upper portion of the first layer metal film 20′.
The rewiring 20 has a portion, where the second layer metal film (second Ni film 17) is not formed at the upper portion of the first layer metal film 20′, in the first layer metal film 20′ extending from the pad (the first electrode pad) 10 to the land section 20, in the region other than the land section formation region. Further, by forming the rewiring 20 using the first mask and the second mask with a plane pattern different from that of the first mask, it is possible to improve the controllability of the wiring dimensions of the rewiring 20, the controllability of the wiring resistance, and the element properties of the semiconductor integrated circuit device. Further, even if miniaturization, high-integration, and multiple pins are accelerated and the wiring length of rewiring 20 is made larger; the element properties of the semiconductor integrated circuit device can be improved. Further, as described later, by making the film thickness of the first layer metal film 20′ larger than that of the second layer metal film (second Ni film 17), the wiring resistance of the rewiring 20 can be reduced without reduction in the adhesive strength between the rewiring 20 and the solder bump 21.
Then, as shown in
Although the film thickness of the second Ni film 17 is not limited to the above-mentioned value (approximately 1 to 3 μm), if the film thickness of the second Ni film 17 is too large, as the stress applied to the end portion of the solder bump 21 is not transmitted to the polyimide resin film 22 at a portion directly under the second Ni film 17, it becomes impossible for the polyimide resin film 22 to reduce and absorb this stress. If the film thickness of the second Ni film 17 is too small, the second Ni film 17 might be destroyed at a portion under the end portion of the solder bump 21 by the stress applied to the end portion of the solder bump 21. Accordingly, it is necessary to optimize the film thickness of the second Ni film 17, taking into account these points.
Then, as shown in
Then, as shown in
Subsequently, as shown in
To connect the solder bump 21 with the surface of the land section 20A, a known method is employed, such as a method where a solder bump 21 formed in advance in a ball shape is supplied to the surface of the land section 20A and is ref lowed, or a method where a solder material in a paste form is printed on the surface of the land section 20A and is ref lowed. If the solder bump 21 formed in a ball shape or the solder material in a paste form is reflowed, the Au film 35 on the surface of the land section 20A diffuses into the solder bump 21.
Then, to thin the semiconductor wafer 1, its back surface is ground. The purpose of thinning the semiconductor wafer 1 is to thin a semiconductor device (IC package) on which a semiconductor chip 1A obtained from the semiconductor wafer 1 is mounted. To thin the semiconductor wafer 1, the semiconductor wafer 1 is fitted to a scriber (not shown) and its back surface is ground by a grinder. A back grind tape (protection tape) is stuck to the device surface of the semiconductor wafer 1 in advance to prevent the device surface from being contaminated or damaged. This back surface grinding makes the thickness of the semiconductor wafer 1 approximately 150 to 400 μm.
Then, the scribe region of the semiconductor wafer 1 is subjected to dicing so that the semiconductor wafer 1 is singulated into pieces. After the back grind tape is removed from the device surface of the semiconductor wafer 1, the scribe region of the semiconductor wafer 1 is diced by a laser beam, a dicing blade, or the both so that the semiconductor wafer 1 is singulated into pieces. Thus the semiconductor chip 1A, shown in
The BGA type semiconductor device 48 is mounted in a mobile electronic device (electronic system) 60 as shown in
The inventors made a vibration test and a drop shock test on a laptop mounting the BGA type semiconductor device 48 shown in
By making the film thickness of the first layer metal film 20′ of the rewiring 20 larger than that of the second layer metal film (second Ni film 17), and the wiring resistance of the rewiring 20 can be reduced without reduction in the adhesive strength between the rewiring 20 and the bump electrode 21. Thus, even without filling underfill resin into the gap between the semiconductor chip 1A and the wiring substrate 40, disconnection of the solder bump (bump electrode) 21 by vibration or drop shock can be reduced.
The semiconductor integrated circuit device in accordance with the embodiment is not limited to the above-mentioned structures, and various changes and modifications can be made without departing from the spirit of the invention.
As shown in
Further, the plane shape of the land section 20A is not limited to a circle, and as shown in
Further, in accordance with the embodiment, of the five layer metal film (barrier metal film 13, seed film 14, Cu film 15, first Ni film 16, and second Ni film 17) forming the rewiring 20, the second Ni film 17 and the first Ni film 16 are formed almost with the same film thickness, but, as shown in
Still further, as shown in
In Embodiment 1, only the land section 20A of the rewiring 20 is formed by the five layer metal film (barrier metal film 13, seed film 14, Cu film 15, first Ni film 16, and second Ni film 17), and the other portion (wiring section) is formed by the four layer metal film, namely the first layer metal film 20′ (barrier metal film 13, seed film 14, Cu film 15, and first Ni film 16). However, in accordance with the embodiment, as shown in
In forming the rewiring 20 in accordance with the embodiment, in the opening 32 of the photoresist film pattern 33 shown in
Further, similarly to Embodiment 1, also in accordance with the embodiment, various modifications and changes of design can be made, as shown in
Still further, the rewiring structure in Embodiment 1 and the rewiring structure in accordance with the embodiment may be implemented in mixture over the same semiconductor chip 1A. A part of a plurality of rewirings 20 formed on the semiconductor chip 1A may have the rewiring structure in Embodiment 1, and the rest part may have the rewiring structure in accordance with the embodiment.
In Embodiments 1 and 2, the rewiring 20 is formed by the five layer metal film (barrier metal film 13, seed film 14, Cu film 15, first Ni film 16, and second Ni film 17), but, as shown in
Further, similarly to Embodiment 1, also in the embodiment, various modifications and changes of design, as shown in
In foregoing Embodiments 1, 2, and 3, the bump electrode (external connection terminal) connected to the land section 20A of the rewiring 20 is formed by the solder bump 21 in a ball shape, but, the bump electrode may be formed by pillar shaped electrodes 21p, as shown in
The height of the top surface of the pillar shaped electrodes 21p is almost the same as that the of the top surface of the polyimide resin film 22, which is an insulation film, and arrangement is made such that the surface of the semiconductor chip 1A is almost flat. The solder bump (bump electrode) 21 in a ball shape may be further formed on the pillar shaped electrodes 21p.
Further, similarly to Embodiment 1, also in the embodiment, various modifications and changes of design, as shown in
In forming the first layer metal film 20′ (barrier metal film 13, seed film 14, Cu film 15, and first Ni film 16) of the rewiring 20 by using the photoresist film pattern (the first mask) 31 described in Embodiment 1, a dummy pattern 50 may be formed at the upper portion of the polyimide resin film 12, which is an insulation film which the dummy pattern 50 is formed by the first layer metal film 20′ (barrier metal film 13, seed film 14, Cu film 15, and first Ni film 16). It is preferable that the dummy pattern 50 does not function as an active component and is in a state of electrically floating. As shown in
As shown in
Similarly to Embodiment 1, in case that only the land section 20A of the rewiring 20 is formed by the five layer metal film (barrier metal film 13, seed film 14, Cu film 15, first Ni film 16, and second Ni film 17) and the other portion (wiring section) is formed by the first layer metal film 20′ (barrier metal film 13, seed film 14, Cu film 15, and first Ni film 16), the unevenness in the density of wiring sections (first layer metal film 20′) in the plane of semiconductor chip 1A becomes higher, as shown in
Accordingly, by disposing, in a region where the density of rewiring 20 is low, a plurality of dummy patterns 50 formed by the first layer metal film 20′, the unevenness in the film thickness by plating in the wafer plane can be reduced in forming the Cu films 15 and the first Ni films 16, which are conductive films forming the rewiring 20. Thus, the reliability of a semiconductor integrated circuit device (semiconductor device) can be improved, and the properties of the semiconductor device can be improved.
Dummy patterns 50 may be provided in a scribe region of a semiconductor wafer. In the periphery of a semiconductor chip, a seal ring wiring formed by a multi-layer wiring is disposed to surround the integrated circuit formation region, and in this situation, dummy patterns 50 may be disposed in the scribe region, which is on the outside of the region where the seal ring wiring is disposed. In this case, the dummy patterns 50 may be formed in the entire scribe region and may be formed only near the seal ring wiring.
Further, it is also possible to form an alignment mark for aligning a mask, using the dummy patterns 50.
In such a manner, arranging the dummy patterns 50 with a structure where the second layer metal film (second Ni film 17) is not formed at the upper portion of the first layer metal film 20′ is a new feature in addition to the above-mentioned and other purposes of the present invention.
Further, various modifications and changes in design, as shown in
In forming the first layer metal film 20′ (barrier metal film 13, seed film 14, Cu film 15, and first Ni film 16) of the rewiring 20 by using the photoresist film pattern 31 (the first mask) described in Embodiment 1, a resistor element R constructed with the first layered metal film 20′ (the barrier metal film 13, the seed film 14, the Cu film 15, and the first Ni film 16) may be formed on the polyimide resin film 12, which is an insulation film.
As shown in
Further, though not shown, in forming the first layer metal film 20′ (barrier metal film 13, seed film 14, Cu film 15, and first Ni film 16) of the rewiring 20, an inductance element formed by the first layer metal film 20′ may be formed, or a capacitance element having the first layer metal film 20′ as one electrode and the third layer wiring 5c as the other electrode may be formed.
By forming passive components, such as a resistance element R, an inductance element, or a capacitance element by using the first layer metal film 20′ of the rewiring 20, unevenness in the properties of elements can be reduced, and the properties of a semiconductor integrated circuit device (semiconductor device) can be improved. Further, the chip size can be easily reduced without adding a new manufacturing process.
Arranging a passive component with a structure where the second layer metal film (second Ni film 17) is not formed at the upper portion of the first layer metal film 20′ is a new feature in addition to the above-mentioned and other purposes of the present invention.
Further, various modifications and changes, as shown in
In Embodiment 1, a stress reducing structure of a solder bump 21 connected to the land section 20A of the rewiring 20 is described, but, in the embodiment, an application to a structure for reducing bonding damage in connecting an external connection terminal (wiring) with the rewiring 20, using a wiring bonding method, will be described.
In case that the external connection terminal is formed by a wiring instead of the solder bump (bump electrode) 21, a rewiring 20 is formed by a structure where the second layer metal film (the second Ni film 17) is not formed at the upper portion of the first layer metal film 20′. Further, polyimide resin film 22 is not formed on the top surface or the side surfaces of this rewiring 20. The rewiring 20 is formed in a state that the rewiring 20 is exposed at the surface of the semiconductor chip 1A.
Further, the semiconductor chip 1A formed with such a rewiring 20 is sealed with a synthetic resin, such as epoxy resin, to configure a plastic package. For such a package, as it is required to make the thickness of the package small, it is desirable that a polyimide resin film 12 is not formed under the rewiring 20. It is desirable to form the rewiring 20 directly on the surface protection film (final passivation film) 8.
However, as the rewiring 20 is disposed above an integrated circuit formed on the device surface of the semiconductor chip 1A, if an insulation film, such as a polyimide resin film 12, is not provided between the surface protection film 8 and the rewiring 20, wiring bonding damage to the integrated circuit becomes significant, with a possibility to cause drop in the reliability of the semiconductor integrated circuit device and drop in the properties of elements. Further, a semiconductor integrated circuit device that uses a low dielectric film (low-k film) with an dielectric constant lower than that of a silicon oxide film, as the inter-layer insulation film to be arranged at the lower portion of the surface protection film 8, possibly causes drop in the reliability and drop in the element properties, because the strength of the inter-layer insulation film is low.
In the embodiment, wiring bonding damage is reduced by a structure described below.
As shown in
The bonding layer 23 formed in the bonding region of the rewiring 20 is formed by a two-layer film of a nickel (Ni) film and a gold (Au) film laminated at the upper portion of the nickel (Ni) film. The Ni film, which is the lower layer film of the bonding layer 23, is formed to improve the adhesiveness between the surface (first Ni film 16) of the rewiring 20 and the bonding layer 23. Further, the Au film, which is the upper layer film of the bonding layer 23, is formed to improve the adhesiveness between the wiring 24 and the bonding layer 23.
A polyimide resin film 12, which is an insulation film, is formed at the lower portion of the bonding region of the rewiring 20. The polyimide resin film 12 is not formed at the lower portion of the other portion (wiring section), excluding the bonding region of the rewiring 20. The polyimide resin film 12 is selectively formed only at the lower portion of the bonding region of the rewiring 20.
Symbol 20F represents a region (flat section) where the surface of the rewiring 20 is flat, and the bonding region (connecting region) in consideration of aligning dimensions for wiring bonding is positioned inside the flat section 20F. That is, the wiring 24 is electrically connected with the rewiring 20 in the bonding region positioned inside the flat section 20F of the rewiring 20.
Further, symbol 12F represents a region (flat section) where the surface of the polyimide resin film 12 is flat. The flat section 12F of the polyimide resin film 12 is disposed to overlap, in plan view, with the flat section 20F of the rewiring 20, and is formed to have a diameter larger than that of the flat section 20F of the rewiring 20. Accordingly, the bonding region of the rewiring 20 is positioned, in plan view, inside the flat section 12F of the polyimide resin film 12. Further, the flat section 12F of the polyimide resin film 12 is disposed to, in plan view, overlap with the bonding layer 23 formed on the top surface of rewiring 20, and is formed to have a diameter larger than that of the bonding layer 23. As described above, the polyimide resin film 12 is formed with a film thickness larger than that of the surface protection film 8.
The side surface of the polyimide resin film 12 is provided with a taper angle (θ) to prevent the side surfaces of the polyimide resin film 12 from becoming a rapid step. It is possible to prevent a rapid change in level for the rewiring 20 formed at a side surface of the polyimide resin film 12. Thus, it is possible to reduce an increase in the resistance of the rewiring 20.
By forming the polyimide resin film 12 at the lower portion of the bonding region of the rewiring 20, bonding damage through connecting the rewiring 20 with the wiring 24 is absorbed by the polyimide resin film 12, and wiring bonding damage to the integrated circuit is reduced. Thus, it is possible to reduce a drop in reliability of the semiconductor integrated circuit device and a drop in the element properties.
Further, the polyimide resin film 12 is selectively formed only at the lower portion of the bonding region of the rewiring 20, and is not formed in other regions. The rewiring 20 is formed directly on the surface protection film 8 except the bonding region. Thus, compared with a case that the polyimide resin film 12 is formed on the entire surface of the semiconductor chip 1A, because the thickness of the semiconductor chip 1A is smaller, the thickness of a package in which this semiconductor chip 1A is resin-sealed can be made smaller.
Further, in case of forming a fuse element by using a wiring layer with the above-mentioned multi-layer wiring structure and melting and cutting the fuse element with a laser or the like, an opening is provided through the inter-layer insulation film formed at the lower portion of the surface protection film 8. Through the opening, the fuse element is melted and cut by irradiation with a laser to perform trimming, relieving a memory defect, or the like. After the trimming, the polyimide resin film 12 is left to cover the opening, and then the reliability of the semiconductor integrated circuit device can be improved.
As described above, the bonding layer 23 formed on the top surface of the rewiring 20 is formed by a two-layer film in lamination of an Au film at the upper portion of a Ni film, but, the Au film, which is the upper layer film of the bonding layer 23, has poorer adhesiveness with resin, compared with the Ni film, which is the lower layer film, and the first Ni film 16 on the surface of the rewiring 20. Therefore, if the bonding layer 23 is formed on the entire top surface of the rewiring 20, the adhesiveness between the resin and the rewiring 20 drops, and the reliability of the package drops. In the embodiment, as the bonding layer 23 is selectively formed on a part (bonding region) of the top surface of the rewiring 20, arrangement is made to reduce a drop in adhesiveness between the resin and the rewiring 20.
Further, in the process of manufacturing a package in which the semiconductor chip 1A is sealed, to make the thickness of the package small, a task (film thinning process) for thinning a semiconductor wafer is performed before a wiring bonding process. In the film thinning process of a semiconductor chip wafer by grinding with a grinder the back surface of the semiconductor wafer for which the preprocess (wafer process) has been completed, the semiconductor chip 1A after dicing is thinned.
In the above-mentioned film thinning process, when aback grind tape is attached to the device surface of the semiconductor chip 1A, the back grind tape is also attached to the top surface of the bonding layer 23 (refer to
To improve the adhesive force between the rewiring 20 and the bonding layer 23 formed on the top surface, as shown in
In this case, not only the contact area between the bonding layer 23 and the rewiring 15 increases but also the bonding layer 23 formed on the side surface of the rewiring 15 does not contact with the back grind tape when the back grind tape is attached to the device surface of the semiconductor chip 1A. Because the adhesive force between the rewiring 20 and the bonding layer 23 is improved, it is possible to reduce occurrence of the defect that the bonding layer 23 peels off from the surface of the rewiring 20 in the film thinning process of the semiconductor chip 1A.
A manufacturing method of a semiconductor integrated circuit device in the embodiment will be described below. A case where the bonding layer 23 is integrally formed to cover the top surface and the side surface of the rewiring 15 will be described below, but, a semiconductor integrated circuit device (refer to
First, a pad opening 9 is formed in the surface protection film 8, according to the process, shown in
Then, as shown in
Then, as shown in
Then, as shown in
Then, as shown in
Then, as shown in
Then, the two-layer photoresist film patterns 42 and 44 having become unnecessary are removed by solvent or ashing, and subsequently, the seed film 14 and the barrier metal film 13, which are exposed in the region from which the photoresist film pattern 42 has been removed and are unnecessary, are removed by wet etching.
Subsequently, the semiconductor wafer is diced through the film thinning process of a semiconductor wafer; a wiring 24 is connected to the rewiring 20 of the obtained semiconductor chip 1A; and then the semiconductor chip 1A, shown in
Subsequently, as shown in
To further improve the adhesive force between the rewiring 20 and the bonding layer 23 formed on it, as shown in
In providing a slit S for the polyimide resin film 12 at a position outside the bonding region of the rewiring 20 in such a manner, the bonding layer 23 above the slit S, namely, the bonding layer 23 positioned outside the bonding region of the rewiring 20 is provided with a step section 46 having a side surface with an angle close to the taper angle (θ). Thus, as the contact area between the rewiring 20 and the bonding layer 23 further increases, the adhesive force between the rewiring 20 and the bonding layer 23 can be further improved.
The embodiment may be combined with one or plural other embodiments from the embodiments 1 to 6 without departing from the spirit. The rewiring 20 in the embodiment may form the rewiring 20s (refer to
The invention developed by the inventors has been described above, based on embodiments, but, the invention is not limited to the embodiments, and various modifications and changes can be made without departing from the spirit of the invention.
For the rewiring 20 in Embodiments 1 to 6, Ni films (first Ni film 16 and second Ni film 17) are employed as the metal films at the upper portion of the CU film 15, but, without being limited to the embodiments, metal films other than Ni films also can be employed as long as they have a function to reduce interdiffusion between the solder bump (bump electrode) 21 and the Cu film 15. Further, the rewiring 20 may be formed from materials with a lower resistance than those of the Cu film 15 and the first Ni film 16.
Further, in Embodiments 2, 3, and 4, the rewiring 20 may form the dummy pattern 50 in Embodiment 5, and the passive elements (the resistance element R, the capacitance element, and the inductance element) in Embodiment 6.
Further, the first layer metal film 20′ and the second layer metal film (second Ni film 17) laminated on it in Embodiments 2, 3, and 4 may form the dummy pattern 50 in Embodiment 5 and the passive elements (resistance element R, capacitance element, and inductance element) in Embodiment 6.
Further, Embodiment 7 may be a semiconductor integrated circuit device applied to IC for a hard disk drive (HDD).
Further, the external connection terminal to be connected to the rewiring 20 is not limited to the solder bump 21 or the wiring 24, and may be a lead terminal by wiring bonding (WB).
The present invention is applicable to a semiconductor integrated circuit device having a rewiring structure, and particularly applicable to a semiconductor integrated circuit device in which an external connection terminal, such as a bump electrode or a bonding wiring, is connected to a first end (land section) of a rewiring formed on the device surface of a semiconductor chip, and an electronic system, such as a mobile electronic device mounting the semiconductor integrated circuit device.
Number | Date | Country | Kind |
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2011-055454 | Mar 2011 | JP | national |