JP2015029127A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem occurring in semiconductor integrated circuit device for automobile use and the like that aluminum pads of a semiconductor chip and the outside are connected with each other by wire bonding with gold wires and the like, in general, due to the convenience of mounting, but such semiconductor integrated circuit device is used for a long time under a relatively high temperature (approximately 150 degrees C) and poor connection occurs due to interaction between aluminum and gold.SOLUTION: A semiconductor device of a present embodiment comprises: an electrolytic gold plated surface film (gold-based metal plated film) provided on an aluminum-based bonding pads on a semiconductor chip which is a part of a semiconductor integrated circuit device (semiconductor device or electronic circuit device) via a barrier metal film; and gold bonding wires (gold-based bonding wire) for mutually connecting external leads provided on a wiring board (wiring base) and the like.

Description

  The present invention relates to a technology that is effective when applied to a technology for interconnecting pad electrodes on a semiconductor chip and the outside in a semiconductor integrated circuit device (semiconductor device or electronic circuit device).

  Japanese Patent Publication No. 2004-533711 (Patent Document 1) or US Pat. No. 6,534,863 (Patent Document 2) describes a lower layer as an alternative to an aluminum pad whose surface is easily oxidized in a semiconductor device having a copper wiring structure. Discloses a technique for bonding a gold wire onto a pad made of TaN (adhesion layer) / Ta (barrier) / Cu (seed) / Ni (first electroplating layer) / Au (second electroplating layer), etc. Yes.

JP-T-2004-533711 US Pat. No. 6,534,863

  In a semiconductor integrated circuit device for in-vehicle use, generally, an aluminum pad on a semiconductor chip and the outside may be interconnected by wire bonding using a gold wire or the like for convenience of mounting. However, since these semiconductor integrated circuit devices are used at a relatively high temperature (around 150 degrees Celsius) for a long time, poor connection such as Kirkendall Void occurs due to the interaction between aluminum and gold.

  The present invention has been made to solve these problems.

  An object of the present invention is to provide a highly reliable semiconductor integrated circuit device.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  The following is a brief description of an outline of typical inventions disclosed in the present application.

  That is, the present invention provides a gold-based surface via a barrier metal film on an aluminum-based or copper-based bonding pad on a semiconductor chip that is a part of a semiconductor integrated circuit device (semiconductor device or electronic circuit device). A metal layer is provided, and a gold-based or copper-based bonding wire bonding or a bonding ball for connection to the outside is provided.

  The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.

  That is, since a gold-based or copper-based bonding wire or bonding ball is bonded onto an aluminum-based or copper-based bonding pad through a gold-based surface film, it can be used at a relatively high temperature for a long time. Connection failure does not occur due to the interaction between aluminum and gold.

FIG. 3 is a vertical device structure diagram (corresponding to a broken line portion in FIG. 3) at the time of completing a pad opening process of a semiconductor chip in a semiconductor integrated circuit device according to an embodiment of the present application; It is a process flow figure showing a flow from a pad opening process to wire bonding among manufacturing processes of a semiconductor integrated circuit device of one embodiment of this application. FIG. 19 is a device cross-sectional process flow diagram (at the time of completion of a pad opening step) for a semiconductor chip (corresponding to the X-X ′ cross section in FIG. 18) in the semiconductor integrated circuit device of one embodiment of the present application; FIG. 20 is a device cross-sectional process flowchart (barrier film forming step) of a semiconductor chip (corresponding to the X-X ′ cross section of FIG. 19) in the semiconductor integrated circuit device of one embodiment of the present application; FIG. 21 is a device cross-sectional process flowchart (resist film coating step) for a semiconductor chip (corresponding to the X-X ′ cross section in FIG. 20) in the semiconductor integrated circuit device of one embodiment of the present application; FIG. 22 is a device cross-sectional process flowchart (resist film opening step) of a semiconductor chip (corresponding to the X-X ′ cross section of FIG. 21) in the semiconductor integrated circuit device of one embodiment of the present application; FIG. 23 is a device cross-sectional process flow diagram (gold plating step) of a semiconductor chip (corresponding to the X-X ′ cross section of FIG. 22) in the semiconductor integrated circuit device of one embodiment of the present application; FIG. 24 is a device cross-sectional process flowchart (resist removal step) of a semiconductor chip (corresponding to the X-X ′ cross section in FIG. 23) in the semiconductor integrated circuit device of one embodiment of the present application; FIG. 25 is a device cross-sectional process flowchart (barrier metal removal step) for a semiconductor chip (corresponding to the X-X ′ cross section in FIG. 24) in the semiconductor integrated circuit device of one embodiment of the present application; FIG. 10 is a top view of a semiconductor chip in the semiconductor integrated circuit device of one embodiment of the present application corresponding to FIG. 9. 1 is a top view of a semiconductor integrated circuit device according to an embodiment of the present application. It is a schematic cross section corresponding to the broken line part of FIG. In FIG. 12, it is a schematic cross section which shows the example which replaced the order of wire bonding. In FIG. 12, it is a schematic cross section which shows the example which replaced the wiring board with the other electronic element on a wiring board. FIG. 13 is a schematic cross-sectional view showing an example in which the die bonding destination of the semiconductor chip is replaced with another electronic element (flip chip bonded) on the wiring board in FIG. Device sectional view (wafer) of a semiconductor chip (corresponding to the section XX ′ in FIG. 25) in a semiconductor integrated circuit device of another embodiment of the present application (an example in which a two-layer polyimide film is provided as an additional final passivation) (When the process is completed). FIG. 4 is a top view of a semiconductor chip in the semiconductor integrated circuit device of one embodiment of the present application corresponding to FIG. 3. FIG. 18 is an enlarged top view (corresponding cross section is shown in FIG. 3) of a broken line part in FIG. It is an enlarged top view of the broken-line part of FIG. 17 in the process corresponding to FIG. It is an enlarged top view of the broken-line part of FIG. 17 in the process corresponding to FIG. It is an enlarged top view of the broken-line part of FIG. 17 in the process corresponding to FIG. It is an enlarged top view of the broken-line part of FIG. 17 in the process corresponding to FIG. It is an enlarged top view of the broken-line part of FIG. 17 in the process corresponding to FIG. It is an enlarged top view of the broken-line part of FIG. 17 in the process corresponding to FIG. FIG. 17 is an enlarged top view in the process corresponding to FIG. 16. It is explanatory sectional drawing for demonstrating the problem of the electroless gold plating on the nickel surface. It is a wafer upper surface enlarged view (1st example; square pad) which shows the mode of the wafer probe test process in the manufacturing process of the semiconductor integrated circuit device of one embodiment of this application. FIG. 28 is an enlarged view of a wafer top surface (first example; square pad) when wire bonding in the example corresponding to FIG. 27 is completed; It is a wafer upper surface enlarged view (2nd example; regular type | mold rectangular pad) which shows the mode of the wafer probe test process in the manufacturing process of the semiconductor integrated circuit device of one embodiment of this application. FIG. 30 is an enlarged view of a wafer upper surface (second example; regular rectangular pad) when wire bonding in the example corresponding to FIG. 29 is completed. It is a wafer upper surface enlarged view (3rd example; deformation | transformation rectangular pad) which shows the mode of the wafer probe test process in the manufacturing process of the semiconductor integrated circuit device of one embodiment of this application. FIG. 32 is an enlarged view of the wafer top surface (third example; deformed rectangular pad) at the completion of wire bonding in the example corresponding to FIG. 31; It is a local schematic sectional drawing of the aluminum pad and bonding wire for demonstrating Kirkendall Void which appears in an aluminum gold joint. It is a local sectional view showing various examples (normal mode) of the bonding state of the bonding wire on the pad in the semiconductor integrated circuit device of one embodiment of the present application. It is a local sectional view showing various examples (lateral shift mode 1) of the bonding state of the bonding wire on the pad in the semiconductor integrated circuit device of one embodiment of the present application. It is a local sectional view showing various examples (lateral shift mode 2) of the bonding state of the bonding wire on the pad in the semiconductor integrated circuit device of one embodiment of the present application. It is a local sectional view for explaining the relation of various dimensions of the bonding structure of the bonding wire on the pad in the semiconductor integrated circuit device of one embodiment of the present application. BRIEF DESCRIPTION OF THE DRAWINGS It is the whole top view at the time of completion of the package process of the semiconductor integrated circuit device (wire bonding type BGA) of one embodiment of this application (the resin sealing body is removed for easy viewing). It is a schematic cross section of FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall top view of a semiconductor integrated circuit device (QFP: Quad Flat Package) according to an embodiment of the present application when a package process is completed (the upper half of a resin sealed body is removed for easy viewing); It is a schematic cross section of FIG. It is a whole top view at the time of completion of the packaging process of the semiconductor integrated circuit device (flip chip type BGA) of one embodiment of this application. It is a schematic cross section of FIG. It is an expanded sectional view of the broken line part of FIG. It is a pad periphery sectional view for explaining various under bump metal structures (two layer structure) in a semiconductor integrated circuit device of one embodiment of this application. FIG. 46 is a cross-sectional view of the periphery of the pad of the modified example of FIG. 45. It is a pad periphery sectional view for explaining various under bump metal structures (multilayer structure of three layers or more) in a semiconductor integrated circuit device of one embodiment of this application.

[Outline of Embodiment]
First, an outline of a typical embodiment of the invention disclosed in the present application will be described.

1. Semiconductor integrated circuit devices including:
(A) an aluminum-based or copper-based pad electrode provided on the device surface of the semiconductor chip;
(B) a barrier metal film provided on the pad electrode;
(C) a surface metal film mainly composed of gold provided on the barrier metal film;
(D) A bonding ball or bonding wire mainly composed of gold or copper bonded onto the surface metal film.

  2. In the semiconductor integrated circuit device according to the item 1, the surface metal film is thicker than the barrier metal film.

  3. 3. In the semiconductor integrated circuit device according to item 1 or 2, the surface metal film is formed by electrolytic plating or sputtering.

  4). 4. In the semiconductor integrated circuit device according to any one of items 1 to 3, the surface metal film is formed by electrolytic plating.

  5. 5. In the semiconductor integrated circuit device according to any one of 1 to 4, the area of the surface metal film is larger than the area of the insulating film opening on the pad electrode.

  6). 6. In the semiconductor integrated circuit device according to any one of 1 to 5, the area of the pad electrode is larger than the area of the surface metal film.

  7). 7. In the semiconductor integrated circuit device according to any one of 1 to 6, the insulating film opening on the pad electrode is inside the surface metal film in a plan view.

  8). 8. In the semiconductor integrated circuit device according to any one of 1 to 7, the surface metal film is inside the pad electrode in plan view.

  9. 5. In the semiconductor integrated circuit device according to any one of items 1 to 4, the surface metal film extends to a region without the pad electrode.

  10. 10. In the semiconductor integrated circuit device according to any one of 1 to 9, the bonding ball is a ball portion of a bonding wire.

  11. 11. In the semiconductor integrated circuit device according to any one of items 1 to 10, the bonding ball is made of a member whose main component is gold.

  12 11. In the semiconductor integrated circuit device according to any one of items 1 to 10, the bonding ball is composed of a member whose main component is copper.

  13. 13. The semiconductor integrated circuit device according to any one of 1 to 12, wherein the pad electrode is an aluminum-based or copper-based pad electrode.

  14 14. In the semiconductor integrated circuit device according to any one of items 1 to 13, the barrier metal film includes titanium as a main component.

  15. 14. In the semiconductor integrated circuit device according to any one of items 1 to 13, the barrier metal film includes, as a main component, one selected from the group consisting of titanium, chromium, titanium nitride, and tungsten nitride.

16. 16. The semiconductor integrated circuit device according to any one of items 1 to 15, further including:
(E) A seed metal film provided between the barrier metal film and the surface metal film.

  17. 16. In the semiconductor integrated circuit device according to item 16, the seed metal film contains palladium as a main component.

  18. 16. In the semiconductor integrated circuit device according to the item 16, the seed metal film has as its main component one selected from the group consisting of copper, gold, nickel, platinum, rhodium, molybdenum, tungsten, chromium, and tantalum.

  19. 19. In the semiconductor integrated circuit device according to any one of items 1 to 18, the pad electrode has a substantially square shape in plan view.

  20. 19. In the semiconductor integrated circuit device according to any one of items 1 to 18, the pad electrode has a substantially rectangular shape in plan view.

  Next, an outline of another embodiment of the invention disclosed in the present application will be described.

1. Semiconductor integrated circuit devices including:
(A) a wiring board;
(B) a first semiconductor chip fixed on the wiring board or on a first electronic element placed on the wiring board;
(C) an aluminum-based or copper-based pad electrode provided on the device surface of the first semiconductor chip;
(D) a barrier metal film provided on the pad electrode;
(E) a seed metal film provided on the barrier metal film;
(F) a surface metal film formed by electrolytic plating using gold provided on the seed metal film as a main component;
(G) an external metal electrode provided outside the first semiconductor chip;
(H) A bonding wire whose main component is gold that interconnects the surface metal film and the external metal electrode.

  2. 2. The semiconductor integrated circuit device according to item 1, wherein the pad electrode is an aluminum-based pad electrode.

  3. In the semiconductor integrated circuit device according to the item 1 or 2, the barrier metal film contains titanium as a main component.

  4). 4. In the semiconductor integrated circuit device according to any one of items 1 to 3, the seed metal film includes palladium as a main component.

  5. 5. In the semiconductor integrated circuit device according to any one of items 1, 2, and 4, the barrier metal film includes, as a main component, one selected from the group consisting of titanium, chromium, titanium nitride, and tungsten nitride. To do.

  6). 6. The semiconductor integrated circuit device according to any one of 1 to 3 and 5, wherein the seed metal film is selected from the group consisting of copper, gold, nickel, platinum, rhodium, molybdenum, tungsten, chromium and tantalum. One of the main ingredients.

  7). 7. In the semiconductor integrated circuit device according to any one of 1 to 6, the first semiconductor chip is fixed on the wiring board.

  8). 7. In the semiconductor integrated circuit device according to any one of 1 to 6, the first semiconductor chip is fixed on the first electronic element on the wiring board.

  9. 9. In the semiconductor integrated circuit device according to any one of items 1 to 8, the external metal electrode is on the wiring board.

  10. 9. The semiconductor integrated circuit device according to any one of 1 to 8, wherein the external metal electrode is on the first electronic element on the wiring board.

  11. 11. The semiconductor integrated circuit device according to any one of 1 to 10, wherein the bonding wire has the surface metal film side as a first bonding point.

  12 11. The semiconductor integrated circuit device according to any one of 1 to 10, wherein the bonding wire has the surface metal film side as a second bonding point.

  13. 13. In the semiconductor integrated circuit device according to any one of items 1 to 12, a metal film containing gold, silver, or palladium as a main component is provided on a surface of the external metal electrode.

14 (A) a wiring board;
(B) a first semiconductor chip fixed on the wiring board or on a first electronic element placed on the wiring board;
(C) an aluminum-based or copper-based pad electrode provided on the device surface of the first semiconductor chip;
(D) a barrier metal film provided on the pad electrode;
(E) a seed metal film provided on the barrier metal film;
(F) a surface metal film mainly composed of gold provided on the seed metal film;
(G) an external metal electrode provided outside the first semiconductor chip;
(H) A method of manufacturing a semiconductor integrated circuit device having a bonding wire whose main component is gold that interconnects the surface metal film and the external metal electrode, and includes the following steps:
(I) forming the seed metal film on substantially the entire surface of the semiconductor wafer;
(II) forming a resist film having an opening on the seed metal film;
(III) A step of forming the surface metal film by forming a plating layer in the opening by electrolytic plating.

  Next, an outline of still another embodiment of the invention disclosed in the present application will be described.

1. Semiconductor integrated circuit devices including:
(A) an aluminum-based or copper-based pad electrode provided on the device surface of the semiconductor chip;
(B) a barrier metal film provided on the pad electrode;
(C) a surface metal film by electrolytic plating containing gold provided on the barrier metal film as a main component;
(D) A bonding ball or bonding wire mainly composed of gold or copper bonded onto the surface metal film.

  2. 2. The semiconductor integrated circuit device according to item 1, wherein the pad electrode is an aluminum-based pad electrode.

  3. In the semiconductor integrated circuit device according to the item 1 or 2, the barrier metal film contains titanium as a main component.

4). 4. The semiconductor integrated circuit device according to any one of items 1 to 3, further including:
(E) A seed metal film provided between the barrier metal film and the surface metal film.

  5. In the semiconductor integrated circuit device according to the item 4, the seed metal film contains palladium as a main component.

  6). 6. The semiconductor integrated circuit device according to any one of items 1, 2, 4, and 5, wherein the barrier metal film includes one selected from the group consisting of titanium, chromium, titanium nitride, and tungsten nitride as a main component. And

  7). 7. The semiconductor integrated circuit device according to item 4 or 6, wherein the seed metal film has one selected from the group consisting of copper, gold, nickel, platinum, rhodium, molybdenum, tungsten, chromium and tantalum as a main component. To do.

[Description format, basic terms, usage in this application]
1. In the present application, the description of the embodiment may be divided into a plurality of sections for convenience, if necessary, but these are not independent from each other unless otherwise specified. Each part of a single example, one part is the other part of the details, or part or all of the modifications. Moreover, as a general rule, the same part is not repeated. In addition, each component in the embodiment is not indispensable unless specifically stated otherwise, unless it is theoretically limited to the number, and obviously not in context.

  Further, in the present application, the term “semiconductor integrated circuit device” mainly refers to a device in which resistors, capacitors, and the like are integrated on a semiconductor chip or the like (for example, a single crystal silicon substrate) with a focus on various transistors (active elements). . Here, as a representative of various transistors, a MISFET (Metal Insulator Semiconductor Effect Transistor) typified by a MOSFET (Metal Oxide Field Effect Transistor) can be exemplified. At this time, as a typical integrated circuit configuration, a CMIS (Complementary Metal Insulator Semiconductor) integrated circuit represented by a CMOS (Complementary Metal Oxide Semiconductor) integrated circuit combining an N-channel MISFET and a P-channel MISFET. Can be illustrated.

  A semiconductor process of today's semiconductor integrated circuit device, that is, an LSI (Large Scale Integration) wafer process, is usually performed from the introduction of a silicon wafer as a raw material to a pre-metal process (interlayer between the lower end of the M1 wiring layer and the gate electrode structure). Starting from the formation of insulating film, contact hole formation, tungsten plug, embedding, etc. (FEOL (Front End of Line) process) and M1 wiring layer formation, final passivation on the aluminum-based pad electrode The process can be roughly divided into BEOL (Back End of Line) processes up to the formation of pad openings in the film (including the process in the wafer level package process). Of the FEOL process, the gate electrode patterning process, the contact hole forming process, and the like are microfabrication processes that require particularly fine processing. On the other hand, in the BEOL process, a via and trench formation process, in particular, a relatively lower local wiring (for example, M1 to M3 in a buried wiring having a structure of about four layers, M1 in a buried wiring having a structure of about 10 layers. In particular, fine processing is required for fine embedded wiring from M to around M5. Note that “MN (usually N = 1 to 15)” represents the N-th layer wiring from the bottom. M1 is a first layer wiring, and M3 is a third layer wiring.

  2. Similarly, in the description of the embodiment, etc., regarding the material, composition, etc., “X consisting of A” etc. is an element other than A unless specifically stated otherwise and clearly not in context. It is not excluded that one of the main components. For example, as for the component, it means “X containing A as a main component”. For example, “silicon member” is not limited to pure silicon, but also includes SiGe alloys, other multi-component alloys containing silicon as a main component, and members containing other additives. Needless to say. Similarly, “silicon oxide film”, “silicon oxide insulating film”, etc. are not only relatively pure undoped silicon oxide (FS), but also FSG (Fluorosilicate Glass), TEOS-based silicon oxide ( Thermal oxide films such as TEOS-based silicon oxide), SiOC (Silicon Oxicarbide) or Carbon-doped Silicon oxide or OSG (Organosilicate glass), PSG (Phosphorus Silicate Glass), BPSG (Borophosphosilicate Glass), CVD Oxide film, SOG (Spin ON Glass), nano-clustering silica (Nano-Clustering Silica: NSC), etc., coated silicon oxide, silica-based low-k insulating film (porous) with pores introduced in the same materials Needless to say, it includes a composite insulating film and other silicon-based insulating films having these as main components.

  In addition to silicon oxide insulating films, silicon nitride insulating films that are commonly used in the semiconductor field include silicon nitride insulating films. Materials belonging to this system include SiN, SiCN, SiNH, SiCNH, and the like. Here, “silicon nitride” includes both SiN and SiNH unless otherwise specified. Similarly, “SiCN” includes both SiCN and SiCNH, unless otherwise specified.

  Note that SiC has similar properties to SiN, but SiON is often rather classified as a silicon oxide insulating film.

  The silicon nitride film is frequently used as an etch stop film in SAC (Self-Aligned Contact) technology, and also used as a stress applying film in SMT (Stress Memory Technique).

  Similarly, “copper wiring”, “aluminum wiring”, “aluminum pad”, “gold bump (gold surface film)”, etc. are not only pure but also aluminum or gold as the main component. In other words, “copper-based wiring”, “aluminum-based wiring”, “aluminum-based pad”, and “gold-based bump (gold-based surface metal film)”. In addition, these expressions indicate that the main part of the part is made of those materials, and needless to say, the whole part is not necessarily made of those materials. Yes.

  The same applies to “barrier metal”, “seed metal” and the like.

  3. Similarly, suitable examples of graphics, positions, attributes, and the like are given, but it is needless to say that the present invention is not strictly limited to those cases unless explicitly stated otherwise, and unless otherwise apparent from the context.

  4). In addition, when a specific number or quantity is mentioned, a numerical value exceeding that specific number will be used unless specifically stated otherwise, unless theoretically limited to that number, or unless otherwise clearly indicated by the context. There may be a numerical value less than the specific numerical value.

  5. “Wafer” usually refers to a single crystal silicon wafer on which a semiconductor integrated circuit device (same as a semiconductor device and an electronic device) is formed, but an insulating substrate such as an epitaxial wafer, an SOI substrate, an LCD glass substrate and the like. Needless to say, a composite wafer such as a semiconductor layer is also included.

  6). In the present application, the “bonding pad” mainly refers to an aluminum-based pad or the like on which a metal multi-layer structure or bump structure (from a barrier metal to a surface metal film) is formed. The bonding pad is not limited to aluminum but may be copper.

  7). In the present application, a relatively thick terminal electrode such as gold (external connection electrode) by electroplating or the like formed on a bonding pad (compared to a barrier metal layer directly below), that is, a “surface metal layer” Is not a bump electrode for direct connection, but may be referred to as a “gold bump”, a “bump electrode”, a “bump electrode layer”, or the like for convenience in consideration of the similarity in shape. The original bump electrode usually has a thickness of about 15 micrometers, but the surface metal layer usually has a thickness of about 1 to 5 micrometers. However, in an example in which an electroplating layer such as copper or nickel is relatively thick under the gold layer as the surface metal layer, when these layers are regarded as a part of the surface metal layer, the total is 15 micrometers. In some cases, it may be about a thickness.

  The term “bonding ball” refers to a ball-shaped metal block formed at the first bonding point or a deformed ball-shaped metal block, or a ball-shaped ball derived from a bonding wire such as a stud bump. It refers to a metal mass or a deformed one.

  8). In the present application, the “wiring board” includes a flexible wiring board, a ceramic wiring board, a glass wiring board, and the like in addition to a commonly used organic wiring board (single layer and multilayer) such as glass / epoxy. The “electronic element” on the wiring board includes a semiconductor device, a semiconductor chip, other chip-like components (resistors, capacitors, etc.) enclosed in a package.

[Details of the embodiment]
The embodiment will be further described in detail. In the drawings, the same or similar parts are denoted by the same or similar symbols or reference numerals, and description thereof will not be repeated in principle.

1. Description of device cross-sectional structure at the time of completion of pad opening on aluminum-based pad in semiconductor integrated circuit device of one embodiment of the present application (mainly FIG. 1)
FIG. 1 is a device cross-sectional view (at the time of completion of a pad opening) showing an example of a cross-sectional structure of a 65 nm technology node device manufactured by a method of manufacturing a semiconductor integrated circuit device according to an embodiment of the present invention. The outline of the device structure of the semiconductor integrated circuit device according to the embodiment of the present application will be described with reference to FIG.

  As shown in FIG. 1, for example, a gate of a P-channel MOSFET or an N-channel MOSFET is formed on a device surface of a P-type single crystal silicon substrate 1 separated by an STI (Shallow Trench Isolation) type element isolation field insulating film 2. An electrode 8 is formed. A silicon nitride liner film 4 (for example, about 30 nm) which is an etch stop film is formed thereon. Further, it is much thicker than the silicon nitride liner film 4 and is composed of a lower layer of an ozone TEOS silicon oxide film (for example, about 200 nm) formed by a thermal CVD method and an upper layer plasma TEOS silicon oxide film (for example, about 270 nm). A metal interlayer insulating film 5 is formed. A tungsten plug 3 is formed through these pre-metal insulating films. This is the pre-metal region PM.

  The first wiring layer M1 thereon is formed on the lower insulating barrier film 14 such as a SiCN film (for example, about 50 nm), the plasma silicon oxide film 15 (for example, about 150 nm) as the main interlayer insulating film, and the like. It is composed of a copper wiring 13 or the like embedded in the wiring groove.

  The second to sixth wiring layers M2, M3, M4, M5, and M6 on the second wiring layer have substantially the same structure. Each layer occupies a composite insulating barrier film (liner film) 24, 34, 44, 54, 64 composed of a lower SiCO film (for example, about 30 nm) / SiCN film (for example, about 30 nm) or the like, and most of the upper layer region. It is composed of main interlayer insulating films 25, 35, 45, 55, 65 and the like. The main interlayer insulating films 25, 35, 45, 55, 65 are carbon-doped silicon oxide films from the lower layer, that is, a SiOC film (for example, about 350 nm) and a plasma TEOS silicon oxide film (for example, about 80 nm) as a cap film. Consists of. Copper embedded wirings 23, 33, 43, 53, 63 including copper plugs and copper wirings are formed through these interlayer insulating films.

  The seventh wiring layer to the eighth wiring layer M7, M8 thereabove have substantially the same structure. Each layer includes insulating barrier films 74 and 84 such as a lower SiCN film (for example, about 70 nm) and upper main interlayer insulating films 75 and 85. The main interlayer insulating films 75 and 85 are composed of a plasma TEOS silicon oxide film (for example, about 250 nm), an FSG film (for example, about 300 nm), a USG film (for example, about 200 nm) as a cap film, and the like from the lower layer. Copper embedded wirings 73 and 83 including copper plugs and copper wirings are formed through these interlayer insulating films.

  The ninth wiring layer to the tenth wiring layer M9, M10 thereabove have substantially the same structure. Each layer is divided into a lower layer and an upper layer. The interlayer insulating film includes insulating barrier films 94b and 104b such as a lower SiCN film (for example, about 70 nm) and an upper main interlayer insulating film. The main interlayer insulating film is composed of lower FSG films 95b and 105b (for example, about 800 nm) and USG films 96b and 106b (for example, about 100 nm) as upper cap films. The in-layer insulating film is composed of insulating barrier films 94a and 104a such as a lower SiCN film (for example, about 50 nm) and an upper main interlayer insulating film. The main-layer insulating film is composed of lower FSG films 95a and 105a (for example, about 1200 nm) and USG films 96a and 106a (for example, about 100 nm) as upper layer cap films. Copper embedded wirings 93 and 103 including copper plugs and copper wirings are formed through the interlayer insulating film and the interlayer insulating film.

  The uppermost wiring layer (pad layer) AP thereabove includes an insulating barrier film such as a lower SiCN film 114 (for example, about 100 nm), a main interlayer insulating film such as an intermediate USG film 117 (for example, about 900 nm), and The outermost plasma SiN119 (for example, about 600 nm) or the like is used for a final passivation film or the like. Further, a tungsten plug 113 is provided through these interlayer insulating films, and an aluminum-based bonding pad 118 (for example, about 1000 nm) is provided on the USG film 117. The aluminum-based bonding pad 118 and the tungsten plug 113 are provided with a lower titanium adhesive layer 151 (for example, about 10 nm) and an upper titanium nitride barrier metal layer 152 (for example, about 30 nm) as necessary. ing. A titanium nitride layer 153 (for example, about 70 nm) is formed on the bonding pad 118, and an opening is formed in this film and the plasma SiN 119 to form a bonding pad opening 163.

  Instead of the aluminum bonding pad 118, a copper bonding pad may be used.

2. Description of processes after bonding pad opening in manufacturing method of semiconductor integrated circuit device according to one embodiment of the present application (mainly FIG. 2, FIG. 3 to FIG. 9, FIG. 16, FIG. 17 to FIG. 24 and FIG. 25)
Next, based on FIG. 3 to FIG. 9, FIG. 17 to FIG. 24, etc., the metal layer structure on the bonding pad (surface metal layer or gold bump, etc.) in the manufacturing method of the semiconductor integrated circuit device according to the embodiment of the present invention. ) Will be described.

  FIG. 2 is a process flow diagram showing the flow from the pad opening process to wire bonding in the manufacturing process of the semiconductor integrated circuit device according to the embodiment of the present application. FIG. 3 is a device cross-sectional process flow diagram (at the time of completion of the pad opening process) of the semiconductor chip (corresponding to the X-X ′ cross section of FIG. 18) in the semiconductor integrated circuit device of one embodiment of the present application. FIG. 4 is a device cross-sectional process / flow diagram (barrier film forming step) of a semiconductor chip (corresponding to the X-X ′ cross section of FIG. 19) in the semiconductor integrated circuit device of one embodiment of the present application. FIG. 5 is a device cross-sectional process / flow diagram (resist film coating step) of a semiconductor chip (corresponding to the X-X ′ cross section of FIG. 20) in the semiconductor integrated circuit device of one embodiment of the present application. FIG. 6 is a device cross-sectional process flowchart (resist film opening step) of the semiconductor chip (corresponding to the X-X ′ cross section of FIG. 21) in the semiconductor integrated circuit device of one embodiment of the present application. FIG. 7 is a device cross-sectional process flowchart (gold plating step) of a semiconductor chip (corresponding to the X-X ′ cross section of FIG. 22) in the semiconductor integrated circuit device of one embodiment of the present application. FIG. 8 is a device cross-sectional process flowchart (resist removal step) of a semiconductor chip (corresponding to the X-X ′ cross section of FIG. 23) in the semiconductor integrated circuit device of one embodiment of the present application. FIG. 9 is a device cross-sectional process flow diagram (barrier metal removal step) of the semiconductor chip (corresponding to the X-X ′ cross section of FIG. 24) in the semiconductor integrated circuit device of one embodiment of the present application. FIG. 16 is a device cross section of a semiconductor chip (corresponding to the XX ′ cross section of FIG. 25) in a semiconductor integrated circuit device of another embodiment of the present application (an example in which a two-layer polyimide film is provided as an additional final passivation). It is a figure (at the time of completion of a wafer process). FIG. 17 is a top view of a semiconductor chip in the semiconductor integrated circuit device according to the embodiment of the present application corresponding to FIG. 18 is an enlarged top view (corresponding cross section is shown in FIG. 3) of the broken line part of FIG. FIG. 19 is an enlarged top view of the broken line portion of FIG. 17 in the step corresponding to FIG. 20 is an enlarged top view of the broken line portion of FIG. 17 in the step corresponding to FIG. FIG. 21 is an enlarged top view of the broken line portion of FIG. 17 in the process corresponding to FIG. FIG. 22 is an enlarged top view of the broken line portion of FIG. 17 in the process corresponding to FIG. FIG. 23 is an enlarged top view of the broken line portion of FIG. 17 in the process corresponding to FIG. 24 is an enlarged top view of the broken line portion of FIG. 17 in the step corresponding to FIG. FIG. 25 is an enlarged top view in the process corresponding to FIG.

  First, as shown in FIG. 3, FIG. 17, and FIG. 18, the main surface of the wafer 101 including the wiring under the pad on which a large number of devices and wirings (formed of silicon oxide films and various metal layers) are formed. A final passivation film 119 such as silicon nitride (which may be an organic film as well as an inorganic film) may be formed thereon (as shown in FIG. 16), a polyimide resin layer 120 may be further formed thereon. ) And a pad opening 163 (an opening formed in the final passivation film 119) is provided in a portion corresponding to the aluminum pad 118 (formed in the pad opening process 201 in FIG. 2). .

  Next, in the state of FIG. 3, in order to remove the natural oxide film on the surface of the bonding pad 118, sputtering etching is performed in an atmosphere containing argon as a main component (sputter etching 202 in FIG. 2).

  Next, as shown in FIGS. 4 and 19, a barrier & seed metal layer (under bump metal film) 67 is formed by sputtering film formation. As the lower barrier metal film 121, for example, a titanium film having a thickness of about 175 micrometers (about 150 to 200 micrometers can be exemplified as a suitable range) can be exemplified (FIG. 2). Ti sputtering step 203). Moreover, as the seed metal film 122 in the upper layer, for example, a palladium film having a thickness of about 175 micrometers (about 150 to 200 micrometers can be exemplified as a suitable range) can be exemplified (see FIG. 2 Pd sputtering step 204).

  Next, as shown in FIG. 5 and FIG. 20, for example, by using a coating system or the like, for example, about 4 micrometers (about 2 to 6 micrometers can be exemplified as a suitable range). A positive resist film 12 having a thickness (which may be negative if necessary) is formed (resist application step 205 in FIG. 2).

Next, as shown in FIGS. 6 and 21, the resist 66 is exposed (for example, i-line light exposure) and developed (for example, alkali development) to form openings 66 (exposure process 206 and development process 207 in FIG. 2). . Subsequently, in order to remove organic contamination at the bottom of the opening 66, oxygen asher processing (oxygen plasma processing) is performed (for example, about 120 seconds at room temperature) (O ₂ ashing step 208 in FIG. 2).

Next, as shown in FIGS. 7 and 22, a surface metal layer (bump electrode) having a thickness of, for example, about 2 micrometers (preferably about 1 to 5 micrometers) is formed by electroplating the opening 66. ) 115 is embedded (electrolytic plating step 209 in FIG. 2). As for the plating conditions, for example, for a 300φ wafer, a sodium sulfite gold plating solution is used, the solution temperature is 55 degrees Celsius, the current value is 0.1 to 1 A / dm ² , and the plating time is about 20 minutes. Can do.

Next, as shown in FIGS. 8 and 23, the resist film 12 is removed (resist removal step 210 in FIG. 2). Subsequently, in order to remove organic contamination, etc., oxygen ashing (oxygen plasma processing) is performed (for example, about 120 seconds at room temperature) (O ₂ ashing step 211 in FIG. 2).
Finally, as shown in FIGS. 9 and 24, unnecessary barrier and seed metal layer 67 (UBM film) is sequentially selectively removed by wet etching using surface metal layer (gold bump electrode) 115 as a mask (FIG. 2). Pd wet etching step 212 and Ti wet etching step 213). Examples of the etchant for the seed metal film 122 include iodine-based etchants, and examples of the etchant for the barrier film 121 include a mixture of ammonia and hydrogen peroxide. Subsequently, oxygen ashing (oxygen plasma processing) is performed (for example, at a normal temperature for about 120 seconds) to remove organic contamination (O ₂ ashing step 214 in FIG. 2).

  This completes the surface metal layer (bump electrode). The surface metal layer (gold bump electrode) 115 is usually made of a relatively pure gold material. However, basically, it can be composed of a gold-based alloy containing gold as a main component. In section 3, the subsequent process of the broken line part in FIG. 9 will be described.

  The barrier metal film may be mainly composed of one selected from the group consisting of titanium, chromium, titanium nitride, and tungsten nitride. The barrier metal film is required to be capable of forming a sputter film and have a sufficient barrier property against gold.

  Further, the seed metal film may be mainly composed of one selected from the group consisting of copper, gold, nickel, platinum, rhodium, molybdenum, tungsten, chromium and tantalum. The seed metal film is required not to react with the barrier metal film, to form a fragile reaction layer with gold, and to be a low-resistance material to the extent that an electrolytic gold layer can be grown.

  FIG. 16 is a modification of the structure described in FIGS. In the example of FIGS. 16 and 25, plasma SiN (inorganic final passivation on a pad) 119 is patterned, and then a polyimide film 120 which is an organic passivation film is formed and patterned (polyimide film opening 123). . This example is advantageous in terms of improving reliability although the processing and structure are complicated. Further, instead of or in addition to this structure, the inorganic final passivation 119 may be a lower inorganic insulating film and an upper polyimide film.

3. Description of assembly process and device structure in manufacturing method of semiconductor integrated circuit device according to one embodiment of the present application (refer to FIGS. 10 to 12 and FIGS. 2 and 9 together)
In this section, following the process described in section 2, the process from the O2 ashing step 214 to the wire bonding step 219 (or stud bump formation when stud bumps are used) in FIG. 2 will be described.

  FIG. 10 is a top view of a semiconductor chip in the semiconductor integrated circuit device according to the embodiment of the present application corresponding to FIG. FIG. 11 is a top view of a semiconductor integrated circuit device according to an embodiment of the present application. 12 is a schematic cross-sectional view corresponding to the broken line portion of FIG.

  As shown in FIG. 2, a probe test 215 (wafer inspection) is performed on the wafer 101 after the O 2 ashing process 214 (FIG. 2) described in FIG. 9 (FIG. 16). Thereafter, back grinding, that is, a BG step 216, is performed in which the back surface of the wafer 101 is ground to a predetermined thickness. Subsequently, a dicing process 217 for dividing the wafer 101 into individual chips 101 is performed using a laser, a rotating blade, or both. A state where the chip 101 is divided is shown below.

  FIG. 10 is an overall top view of the semiconductor chip 101 in the semiconductor integrated circuit device according to the embodiment of the present application corresponding to FIG. 9 (or FIG. 16). In the figure, almost the entire surface of the semiconductor chip 101 is covered with a final passivation 119 (120), and a surface metal layer 115 is provided on each peripheral pad.

  Next, as shown in FIG. 11 and FIG. 12 (enlarged cross section of the broken line portion in FIG. 11), for example, a wiring board 133 (ceramic board, flexible wiring board, etc.) such as an organic multilayer wiring board (may be a single-layer wiring board). The semiconductor chip 101 is die-bonded via an adhesive layer 130 (die attach film, paste, etc.) (die bonding step 218 in FIG. 2).

  Next, as shown in FIG. 12, the surface metal layer 115 (surface gold) on the bonding pad 118 on the chip 101 (die) is used by using a bonding wire 132 and a bonding capillary 171 whose main components are gold. Layer) and a lead portion 131 (in this case, on the wiring substrate 133) of the chip 101 are connected (in the wire bonding step 219 in FIG. 2, the bonding temperature is about 150 degrees Celsius, for example). In this case, the surface metal layer 115 side is ball bonding with the ball 134 (primary bonding portion 135), and the lead portion 131 side is wedge bonding (secondary bonding portion 136) (both are set as “ball bonding”). ”,“ Ball / Wedge Bonding ”,“ Nail Head Bonding ”, etc.). As a bonding method, thermo-sonic bonding (by a combination of heating and ultrasonic energy) is suitable because of the demand for low temperature. In this way, what is bonded with the ball 134 on the chip side (the chip side is the secondary bonding portion) is distinguished from “reverse bonding” as shown in FIG. 14 in the next section, in particular “forward bonding”. That's it.

  In this embodiment, a surface metal whose main component is gold through an intermediate metal layer such as a barrier metal on an aluminum-based (copper-based) bonding pad on the semiconductor chip side that is characteristically delicate Since the layer is formed, gold-based bonding wires containing gold as the main component (for example, allowing palladium and other additives) can be used for a long time at high temperatures even when interconnected with a wiring board, etc. Undesirable progress of the reaction can be avoided.

  The surface of the lead portion 131 is desirably a so-called bonding metal film (a metal film containing gold, silver, palladium, or an alloy thereof as a main component) from the viewpoint of reliability.

4). Description of Modification Example of Assembly Process and Device Structure in Manufacturing Method of Semiconductor Integrated Circuit Device of One Embodiment of the Present Application (FIGS. 13 to 15)
Here, various modifications to the assembly process and the assembly structure described in Section 3 will be described.

  FIG. 13 is a schematic cross-sectional view showing an example in which the order of wire bonding is changed in FIG. FIG. 14 is a schematic cross-sectional view showing an example in which the wiring board is replaced with another electronic element on the wiring board in FIG. FIG. 15 is a schematic cross-sectional view showing an example in which the die bonding destination of the semiconductor chip is replaced with another electronic element (flip chip bonded) on the wiring board in FIG.

(1) Explanation of reverse order bonding method (reverse direction bonding) (FIG. 13)
As shown in FIG. 13, the order of wire bonding in FIG. 12 may be reversed. That is, reverse bonding. In this case, since the surface metal layer 115 side becomes the secondary bonding portion 136, there is an advantage that the wire loop is lowered. The direct connection to the normal aluminum-based bonding pad 118 has a problem of impact to the device, but in this example, since there is a relatively thick surface gold layer 115, the influence of the problem is relatively small.

  As in section 3, the surface of the lead 131 is a so-called bonding metal film (a metal film containing gold, silver, palladium, or an alloy thereof as a main component) from the viewpoint of reliability. Is desirable.

(2) Description of wire bonding method between two chips (Fig. 14)
As shown in FIG. 14, this example differs from FIGS. 12 and 13 in that the semiconductor chip 101 is not directly on the wiring board 133, but another semiconductor chip 101 b (more broadly a device chip) on the wiring board 133, that is, It is die-bonded on a base chip (the same applies to the base electronic element). Here, when the surface metal layer 115 on the semiconductor chip 101 and the surface metal layer 115 on the base chip 101 b are interconnected by the bonding wire 132, the other semiconductor chip 101 b is on the same pad as the semiconductor chip 101. In the case of a metal multilayer structure, both bonding parts have a highly reliable structure.

  Note that reverse bonding can also be applied.

(3) Description of flip-chip die bonding method (FIG. 15)
As shown in FIG. 15, the die bonding of the semiconductor chip 101 is performed by another method in which flip chip bonding (connection by solder bumps 137 to the solder bump land electrodes 138 on the wiring substrate 133) is performed on the wiring substrate 133. You may perform on the semiconductor chip 101b, ie, a base chip. In this case, the interconnection by the bonding wire 132 becomes the surface metal layer 115 on the semiconductor chip 101 and the electrode (lead part) on the device chip other than the base chip 101b or the lead part 131 on the wiring substrate 133. .

  As in section 3, the surface of the lead 131 is a so-called bonding metal film (a metal film containing gold, silver, palladium, or an alloy thereof as a main component) from the viewpoint of reliability. Is desirable.

  Also, reverse bonding can be applied.

5. Description of various package forms of the semiconductor integrated circuit device of one embodiment of the present application (mainly FIGS. 38 to 44)
In this section, various package forms of a semiconductor integrated circuit device according to an embodiment of the present application (the same applies to other embodiments) will be described.

  FIG. 38 is an overall top view of the semiconductor integrated circuit device (wire bonding type BGA) according to the embodiment of the present application when the package process is completed (resin sealing body is removed for easy viewing). FIG. 39 is a schematic cross-sectional view of FIG. FIG. 40 is an overall top view of the semiconductor integrated circuit device (QFP: Quad Flat Package) according to one embodiment of the present application when the package process is completed (the upper half of the resin sealed body is removed for easy viewing). 41 is a schematic cross-sectional view of FIG. FIG. 42 is an overall top view of the semiconductor integrated circuit device (flip chip type BGA) according to the embodiment of the present application when the package process is completed. 43 is a schematic cross-sectional view of FIG. 44 is an enlarged cross-sectional view of a broken line portion of FIG.

  First, a wire bonding type BGA using a wiring board 133 (for example, an organic multilayer wiring board) will be described with reference to FIGS. As shown in FIGS. 38 and 39, a device chip 101 (semiconductor chip) is die-bonded on a wiring substrate 133 via an adhesive layer 130 (for example, a die attach film or a die bond paste). ing. A plurality of surface metal layers 115 (on bonding pads) are provided on the upper surface of the device chip 101, and bonding wires 132 are provided between the device chip 101 and a plurality of external leads 131 provided on the upper surface of the wiring substrate 133. ,It is connected. In this example, a bonding ball 134 is formed on the surface metal layer 115 side. The upper surface side of the wiring board 133 is sealed with a sealing resin 181. On the other hand, a plurality of solder bumps 137 are provided on the lower surface side of the wiring board 133.

  Next, a wire bonding type QFP (resin package using a lead frame) will be described with reference to FIGS. As shown in FIGS. 40 and 41, an adhesive layer 130 (for example, a die attach film or a die bond paste) is formed on the die pad 145 held by the four die pad support bars 146. Etc.), the device chip 101 (semiconductor chip) is die-bonded. A plurality of surface metal layers 115 (on bonding pads) are provided on the upper surface of the device chip 101, and are connected to the plurality of leads 131 by bonding wires 132. In this example, a bonding ball 134 is formed on the surface metal layer 115 side. The inside of the lead 131, the die pad support bar 146, the die pad 145, the device chip 101, and the bonding wire 132 are sealed with a resin sealing body 181 (sealing resin).

  Next, a flip chip type BGA (for example, flip chip connection using a gold stud bump) will be described with reference to FIGS. 42 to 44, a plurality of land pads 155 are provided on the wiring substrate 133, and a plurality of surface metal layers 115 (bonding) on the lower surfaces of the land pads 155 and the device chip 101 are provided. -Under the pad) The gold-based stud bump 157 (which may be copper-based) is connected to each other via a solder layer 156 (for example, lead-free solder made of 3.5% by weight of silver and the rest of tin). It is connected. This connection is reinforced by underfill resin 148 (for example, epoxy resin containing silica powder). On the lower surface of the wiring board 133, solder bumps 137 for external connection (for example, 3.5% by weight of silver, 0.5% by weight of copper, and the rest are lead-free solder made of tin, etc.) are provided.

6). Explanation of wafer probe inspection and the like in the method of manufacturing a semiconductor integrated circuit device of one embodiment of the present application (mainly FIGS. 27 to 32)
This section further describes the probe test 215 and wire bonding process 219 described in FIG.

  FIG. 27 is an enlarged top view of the wafer (first example; square pad) showing the wafer probe test process in the manufacturing process of the semiconductor integrated circuit device according to the embodiment of the present application. FIG. 28 is an enlarged view of the wafer top surface (first example: square pad) when wire bonding is completed in the example corresponding to FIG. FIG. 29 is an enlarged top view of the wafer (second example; regular rectangular pad) showing the state of the wafer probe test process in the manufacturing process of the semiconductor integrated circuit device according to the embodiment of the present application. FIG. 30 is an enlarged view of the wafer top surface (second example: regular rectangular pad) at the completion of wire bonding in the example corresponding to FIG. FIG. 31 is an enlarged top view of the wafer (third example; deformed rectangular pad) showing the state of the wafer probe test process in the manufacturing process of the semiconductor integrated circuit device according to the embodiment of the present application. FIG. 32 is an enlarged view of the wafer top surface (third example; deformed rectangular pad) at the completion of wire bonding in the example corresponding to FIG. Based on these, the relationship between the shape (including orientation) of the bonding pad and the surface metal layer and the probe needle and the bonding wire will be described.

  First, the probe test 215 (FIG. 2) using a square pad will be described with reference to FIG. As shown in FIG. 27, in plan view, the surface metal layer 115 and the bonding pad 118 are concentrically arranged (in this case, the bonding pad 118 is slightly larger) (the center substantially shares the center). It has become. Here, most parts other than the surface metal layer 115 and the bonding pad 118 are covered with plasma SiN 119 (inorganic final passivation on the pad) or the like. In the probe test 215, the plurality of probe needles 221 are brought into contact with the corresponding plurality of surface metal layers 115. When the surface metal layer 115 is a gold-based metal material (high-purity gold or metal containing gold as a main component), the contact property is excellent. This is because the gold-based metal material hardly generates a natural oxide film on the surface. Therefore, the contact damage is inevitably small (the contact load and the overdrive amount can be relatively small values). This is effective when, for example, a mechanically fragile Low-k layer film or the like is used for the wiring interlayer insulating film under the pad.

  Next, the wire bonding step 219 using a square pad will be described with reference to FIG. As shown in FIG. 28, in this case, a bond with the bonding wire 132 (bonding ball 134) is formed at the same location where the probe needle 221 contacts during the probe test 215. Unlike the case where the surface of the Al pad is turned over due to the presence of the surface metal layer 115 and the contact trace remains, the contact damage is small (almost no contact trace remains), so that the bonding characteristics are not adversely affected. There are benefits.

  Next, a probe test 215 and a wire bonding step 219 (FIG. 2) using a regular rectangular pad will be described with reference to FIGS. 29 and 30. FIG. As shown in FIG. 29 and FIG. 30, in a plan view, the surface metal layer 115 and the bonding pad 118 are concentrically arranged (in the center, the bonding pad 118 is slightly larger in this case). Share). However, in this example, since the surface metal layer 115 and the bonding pad 118 have a rectangular shape, wire bonding can be performed at a location different from the portion where the probe needle 221 contacts. Therefore, in various probe tests, for example, repeated inspection (re-inspection) is performed, and even when contact damage becomes relatively large, the influence on the wire bonding can be avoided. .

  Next, a probe test 215 and a wire bonding step 219 (FIG. 2) using a deformed rectangular pad will be described with reference to FIGS. 31 and 32. FIG. As shown in FIGS. 31 and 32, in a plan view, the surface metal layer 115 has a rectangular shape, and the bonding pad 118 has a substantially square shape. In addition, the orientations or positional relationships are partially overlapped but are shifted from each other. The surface metal layer 115 is formed on the plasma SiN (inorganic final passivation on the pad) 119 via an under bump metal layer (barrier and seed metal layer) 67 in a portion without the bonding pad 118 or the like. Has been. Therefore, the same merit as the regular rectangular pad described above can be obtained. Normally, it is desirable that a cushioning material (impact mitigation layer) such as a bonding pad 118 exists below the probed portion, but when the surface metal layer 115 is a gold-based metal material, hardness can be secured, Since contact damage can be made relatively small in many cases, even if the probe needle 221 is contacted at a portion where the bonding pad 118 is not present as shown in FIG. 31, the underlying plasma SiN (inorganic final passivation on the pad) ) Damage to 119 can be reduced. The wire bonding point can be set at a position where bonding can be performed on the surface metal layer 115. However, as shown in FIG. 32, by setting the bonding pad 118 at a portion, the probability of occurrence of damage. Can be reduced.

7). Description of various surface metal layer lower metal layer structures (or under bump metal structures) of the semiconductor integrated circuit device of one embodiment of the present application (mainly FIGS. 45 to 47)
Here, the various metal layer structures below the surface metal layer described above will be further described.

  FIG. 45 is a pad peripheral cross-sectional view for explaining various under-bump metal structures (two-layer structure) in the semiconductor integrated circuit device of one embodiment of the present application. FIG. 46 is a cross-sectional view of the periphery of the pad of the modified example of FIG. FIG. 47 is a pad peripheral cross-sectional view for explaining various under-bump metal structures (multilayer structure of three or more layers) in the semiconductor integrated circuit device of one embodiment of the present application.

  First, a basic surface metal layer-under-metal layer structure of a semiconductor integrated circuit device according to an embodiment of the present application will be described with reference to FIG. In this case, as shown in FIG. 45, for example, a barrier metal film 121 containing titanium as a main component on an aluminum-based bonding pad 118 (thickness is 0.175 micro · In addition, a seed metal film 122 containing palladium as a main component (with a thickness of about 0.175 μm, for example, by sputtering film formation), and gold on the main metal film 122 Electrolytic plating gold-based bump electrode 115 (gold bump, surface metal layer, or over pad metal) as a component is laminated (thickness is about 2.8 micrometers, for example, as a range, for example, 1 to 3 micrometers). Here, the titanium film 121 is an interdiffusion barrier for aluminum and gold. The palladium film 122 is a seed film for forming the electroplated gold-based surface metal layer 115.

  Next, a modification of the example of FIG. 45 will be described based on FIG. As shown in FIG. 46, in this structure, an electrolytic nickel plating layer 127 (thickness is, for example, about 2 micrometers) is interposed between the seed metal film 122 and the electrolytic plating gold surface metal layer 115. It has been made. Nickel is harder than gold and is effective in reducing damage caused by wire bonding.

  Next, an example of an under bump metal structure having a multilayer structure of three or more layers will be described with reference to FIG. In this case, as shown in FIG. 47, for example, a barrier metal film 124 containing chromium as a main component on an aluminum-based bonding pad 118 (the thickness is 0.075 micro- In addition, a seed metal film 125 containing copper as a main component (with a thickness of about 0.25 micrometer, for example, by sputtering), and copper as a main component. Electrolytic copper plating layer 126 as a component (thickness is, for example, about 2 micrometer, range is, for example, about 1 micrometer to 10 micrometer as required), and further nickel Electrolytic nickel plating layer 127 (thickness is, for example, about 2 micrometers), and the like. An electroplated gold-based bump electrode 115 (gold bump, surface metal layer, or over pad metal) containing gold as a main component is laminated thereon (thickness is about 2.8 micrometers, for example). The range is, for example, about 1 to 3 micrometers). Here, the chromium film 124 is an interdiffusion barrier for aluminum and copper. The copper film 125 is a seed film for forming the copper electrolytic plating film 126.

  This structure is characterized by a relatively thick and hard nickel layer and copper layer under the electroplated gold bump electrode 115, which is effective in reducing damage caused by wire bonding. It can also be used as a highly reliable rewiring (low resistance rewiring) consisting of layers. It is also effective in reducing the resistance of the external terminal.

8). Discussion on various embodiments (mainly FIG. 26 and FIGS. 33 to 37)
In this section, explanations of features, technical effects, etc. common to each embodiment or unique to each embodiment, or other supplementary explanations will be given.

  FIG. 26 is an explanatory sectional view for explaining a problem of electroless gold plating on the nickel surface. FIG. 33 is a local schematic cross-sectional view of an aluminum pad and a bonding wire for explaining a Kirkendall Void appearing in an aluminum gold joint. FIG. 34 is a local sectional view showing various examples (normal mode) of bonding states of bonding wires on pads in the semiconductor integrated circuit device of one embodiment of the present application. FIG. 35 is a local cross-sectional view showing various examples (lateral shift mode 1) of bonding states of bonding wires on pads in the semiconductor integrated circuit device of one embodiment of the present application. FIG. 36 is a local cross-sectional view showing various examples (lateral shift mode 2) of bonding states of bonding wires on pads in the semiconductor integrated circuit device of one embodiment of the present application. FIG. 37 is a local cross-sectional view for explaining the relationship of various dimensions of the bonding structure of the bonding wire on the pad in the semiconductor integrated circuit device of one embodiment of the present application.

  First, based on FIG. 26, the problem in the case of using electroless gold plating (substantially the same for copper and nickel as well as gold) in place of electrolytic gold plating is the problem of electroless gold plating (replacement gold plating) on the nickel surface 301. ) Will be described as an example. As shown in FIG. 26, electroless gold plating is formed by attaching a gold member 302 to a portion 303 from which nickel as a base metal has been removed. Since the plating reaction stops in the stage where the gold plating region 302 is covered, the gold plating region 302 itself is in a porous state. Therefore, nickel is easily deposited from the porous portion, and the deposited nickel is oxidized to form nickel oxide (NiO). When this nickel oxide is present on the gold plating region 302, it is difficult to attach the bonding wire, and even if it is attached, it is easy to peel off. In addition, since the plating reaction stops when the gold plating region 302 once covers the surface, it is generally difficult to ensure a plating thickness of about 100 nm (about 0.1 micrometer) or more. Furthermore, since a void is formed at the interface between the nickel surface 301 and the gold plating region 302, sufficient adhesion (adhesion) cannot be ensured, and the gold layer is likely to be peeled off (interfacial separation).

  On the other hand, in electrolytic plating, the plating reaction proceeds by an external electric field, so that it is possible to form a dense plating film, and it is easy to form a film thickness thicker than electroless gold plating. Needless to say, this is not limited to the case where the base is nickel.

Next, based on FIG. 33, there is a problem when a bonding wire (or bonding ball) such as a gold-based material is directly bonded without interposing a metal-based surface metal layer 115 on the aluminum-based pad. Will be described. If the temperature is kept at a relatively low temperature (for example, about 150 degrees Celsius) for a long time with a bonding wire such as a gold-based bonding wire bonded directly on the aluminum-based pad, as shown in FIG. In the vicinity, Au—Al-based intermetallic compound layers 140, 141, 142, and 143 (for example, Au ₄ Al layer 140, Au ₂ Al layer 141, Au ₅ Al ₂ layer 142, and AuAl ₂ layer 143) appear. Along with this, a void 139 (kirkendall void) is formed on the bonding ball 134 side, causing breakage of the joint. This is because the gold diffusion rate in the Au—Al intermetallic compound layers 140, 141, 142, 143 is compared with the aluminum diffusion rate in the Au—Al intermetallic compound layers 140, 141, 142, 143. Because it ’s much faster. That is, as a result of gold ions moving to the aluminum-based pad 118 side at a high speed, a large number of vacancies are formed thereafter, and gradually agglomerate into voids.

  On the other hand, by interposing a gold-based surface metal layer 115 on the aluminum-based pad 118 with a barrier layer in between, the generation of voids can be effectively prevented while securing bonding characteristics.

  Next, various modes of bonding of the gold-based (or copper-based) bonding wire 132 (or bonding ball 134) to the surface metal layer 115 such as a gold-based material will be described with reference to FIGS. FIG. 34 shows the normal mode. That is, here, the bonding ball 134 is within the upper surface of the surface metal layer 115. The example of FIG. 35 is one of the shift modes, and the main joint portion (ball center portion) of the bonding ball 134 is within the upper surface of the surface metal layer 115, so that there is no problem in characteristics. It is. The example of FIG. 36 is another one of the shift modes, where the main joint portion (ball center portion) of the bonding ball 134 is within the upper surface of the surface metal layer 115, but the ball 134 itself is deformed or The ball 134 deforms the end of the surface metal layer 115, and the lower end of the ball 134 reaches the surface of plasma SiN (inorganic final passivation on the pad) 119. Also in this case, it is rare that cracks or the like occur in plasma SiN (inorganic final passivation on the pad) 119 or the like due to the impact absorbing ability of the surface metal layer 115, and there is a problem in terms of product characteristics. There are few. As described above, the main features described so far are also applicable to the cases shown in FIGS. 34 to 36. In other words, the cases shown in FIGS. It can be said that the main part of the part is in a region almost immediately above the bonding pad.

  Next, based on FIG. 37 (see FIGS. 28, 30, 32, and 45 to 47), the bonding structure of the bonding wires on the pads in the semiconductor integrated circuit device of each embodiment of the present application, that is, The relationship between various dimensions of the Over Pad Metal structure will be described. As shown in FIG. 37, in the standard layout (normal structure), the pad width LP is the widest in all directions, the pad opening width LW is the narrowest in all directions, and the surface metal layer width LB is in all directions. Between them. Therefore, in a plan view, the surface metal layer 115 is included in the bonding pad 118 (the surface metal layer 115 is smaller in area), and similarly, the bonding pad opening 163 is formed in the surface metal layer 115. It is contained inside (the bonding pad opening 163 is smaller in area).

  However, the irregular structure as shown in FIG. 32 only satisfies such a magnitude relationship and an inclusion relationship for a specific lateral direction. Not all such relationships are satisfied in the vertical direction.

  Similarly, as shown in FIG. 37, in the standard structure, the surface metal layer thickness (or equivalent thickness) TB is equal to the barrier metal layer thickness TU (usually barrier metal). It is thicker than the thickness of the film 121. The reason why the surface metal layer 115 is relatively thick is to secure a substantial characteristic as a bonding pad. However, it is naturally conceivable that the thickness TB of the surface metal layer and the thickness TU of the barrier metal layer are approximately the same due to changes in peripheral parameters or the like, and the relationship between the two may be reversed. . Therefore, the surface metal layer can be formed not only by electrolytic plating, but also by sputtering film formation or electroless plating, for example, when it is thin or only partially. In particular, sputtering film formation is a processing method of photo-etching after film formation on almost the entire wafer, so that unnecessary (discarded) parts are generated, the internal stress of the film is strong, and warping of the wafer is caused. Although there is a demerit that it is often the cause, there is an advantage that a very clean film can be formed compared to the plating film.

  46 and 47, when there are a plurality of electrolytic plating layers on the barrier metal layer 121 (or the barrier & seed metal layer 67), the thickness TB of the surface metal layer is determined as It is theoretically consistent to take the thickness of the entire electrolytic plating layer. In addition, in the case of a homogeneous layer such as a seed metal layer (for example, copper) and an upper electrolytic plating layer (for example, copper), the seed metal layer has a part of the thickness of the electrolytic plating layer. It is actually more appropriate to configure.

  In FIG. 37, the width LB of the surface metal layer can be made wider than the width LP of the pad in a fixed orientation or direction as shown in FIG. By doing so, the freedom degree of a bonding point (place to wire-bond) can be increased. Similarly, the width LB of the surface metal layer can be made wider than the width LP of the pad in all directions or directions. Furthermore, the width LB of the surface metal layer can be made smaller than the width LW of the pad opening in a certain direction or direction (or all directions or directions). By doing so, not only can the consumption of gold be reduced, but also there are merits that various layout flexibility increases.

9. Summary The invention made by the present inventor has been specifically described based on the embodiments. However, the present invention is not limited thereto, and it goes without saying that various changes can be made without departing from the scope of the invention.

  For example, in the above-described embodiment, the semiconductor chip having damascene wiring (embedded wiring having copper, silver, etc. as a main wiring element) such as copper damascene wiring has been specifically described, but the present invention is limited thereto. Needless to say, the present invention can be applied to a semiconductor chip having an aluminum-based normal wiring (non-embedded wiring).

  In the above-described embodiment, the description has been given mainly using the gold-based wire as an example of the bonding wire used as the material of the bonding wire or the bonding ball (including the stud bump). However, as the bonding wire, In addition to gold-based wires (high-purity gold or those added with various additives), copper-based wires (high-purity copper, oxygen-free copper, or those added with various additives), palladium-based wires Needless to say, (a metal material containing palladium as a main component) or the like can also be applied.

1 Semiconductor substrate (P-type single crystal silicon substrate)
2 Device isolation field insulating film 3 Tungsten plug 4 Silicon nitride liner film 5 Pre-metal interlayer insulating film 8 Gate electrode 12 Resist film 13 Copper wiring 14 Insulating barrier film 15 Plasma silicon oxide film 23 Copper embedded wiring 24 Composite insulating property Barrier film 25 Main interlayer insulating film 33 Copper embedded wiring 34 Composite insulating barrier film 35 Main interlayer insulating film 43 Copper embedded wiring 44 Composite insulating barrier film 45 Main interlayer insulating film 53 Copper embedded wiring 54 Composite insulating barrier film 55 Main interlayer Insulating film 63 Copper embedded wiring 64 Composite insulating barrier film 65 Main interlayer insulating film 66 Resist opening 67 Under bump metal layer (barrier and seed metal layer)
73 Copper embedded wiring 74 Insulating barrier film 75 Main interlayer insulating film 83 Copper embedded wiring 84 Insulating barrier film 85 Main interlayer insulating film 93 Copper embedded wiring 94a, 94b Insulating barrier film 95a, 95b FSG film 96a, 96b USG film 101 Semiconductor substrate (including wiring under pad) Semiconductor substrate, device chip, or semiconductor wafer 101b Other device chip 103 Copper embedded wiring 104a, 104b Insulating barrier film 105a, 105b FSG film 106a, 106b USG film 113 Tungsten plug 114 SiCN film 115 Gold bump electrode (Gold bump, surface metal layer, or over pad metal)
117 USG film 118 Bonding pad 119 Plasma SiN (Inorganic final passivation on the pad)
120 Polyimide coating film 121 Titanium barrier film (barrier metal film)
122 Palladium seed film (seed metal film)
123 Polyimide film opening 124 Chromium barrier film 125 Copper seed film 126 Copper electroplating film 127 Nickel electroplating film 130 Adhesive layer (die attach film)
131 External lead (lead)
132 Bonding Wire 133 Wiring Board 134 Bonding Ball 135 Primary Bonding Part 136 Secondary Bonding Part 137 Solder Bump 138 Solder Bump Land Electrode 139 Void (Carkendall Void)
140, 141, 142, 143 Au-Al intermetallic compound layer 145 Die pad 146 Die pad support bar 148 Underfill resin 151 Titanium adhesive layer 152 Titanium nitride / barrier metal layer 153 Titanium nitride layer 155 Land・ Pad 156 Solder layer 157 Gold stud ・ Bump (gold bonding ball)
163 Bonding pad opening (insulating film opening just above the bonding pad)
171 Bonding Capillary 181 Resin Sealed Body (Sealing Resin)
201 Pad Opening 202 Sputter Etch 203 Titanium Sputter 204 Pd Sputter 205 Resist Application 206 Exposure 207 Development 208 O ₂ Ashing 209 Gold Electroplating 210 Resist Removal 211 O ₂ Ashing 212 Pd Wet Etch 213 Titanium Wet Etch 214 O ₂ Ashing 215 Probe inspection (wafer inspection)
216 BG (Back Grinding)
217 Dicing (Pelletize)
218 Die bonding 219 Wire bonding 221 Probe needle 301 Nickel layer 302 Gold plating area 303 Nickel exposed area AP Top layer wiring layer (pad layer)
LB Surface metal layer width LP pad width LW pad opening width M1 first wiring layer M2 second wiring layer M3 third wiring layer M4 fourth wiring layer M5 fifth wiring layer M6 sixth wiring layer M7 seventh wiring layer M8 8th wiring layer M9 9th wiring layer M10 10th wiring layer TB Surface metal layer thickness TU Barrier metal layer thickness

Claims (13)

A semiconductor chip having a main surface on which pad electrodes are disposed;
A metal wire electrically connected to the pad electrode of the semiconductor chip,
A surface metal film is formed on the surface of the pad electrode of the semiconductor chip,
In a plan view of the semiconductor chip from the main surface side, the surface metal film has a rectangular shape having a pair of long sides and a pair of short sides, and has a first portion and a second portion. And
One end of the metal wire is a semiconductor device electrically connected to the first portion of the surface metal film. The semiconductor device according to claim 1,
The semiconductor device, wherein the second portion of the surface metal film is a portion capable of contacting a probe needle. The semiconductor device according to claim 1,
In the plan view, the pad electrode has a rectangular shape having a set of long sides and a set of short sides. The semiconductor device according to claim 3.
A semiconductor device in which a wiring interlayer insulating film including a low-k layer film is formed under the pad electrode. The semiconductor device according to claim 3.
The semiconductor device, wherein a planar area of the surface metal film is smaller than a planar area of the surface of the pad electrode. The semiconductor device according to claim 1,
On the main surface of the semiconductor chip, an insulating film in which an opening is formed is disposed,
The semiconductor device, wherein the part of the surface of the pad electrode is exposed from the opening of the insulating film. The semiconductor device according to claim 6.
A barrier metal film is disposed between the first portion of the pad electrode and the surface metal film,
The barrier metal film is a semiconductor device in contact with an upper surface around the opening of the insulating film. The semiconductor device according to claim 7,
A semiconductor device, wherein a seed metal film is disposed between the barrier metal film and the surface metal film. The semiconductor device according to claim 8,
The semiconductor device, wherein the surface metal film is thicker than each of the barrier metal film and the seed metal film. The semiconductor device according to claim 1,
A semiconductor device, wherein a ball portion is formed at the one end of the metal wire, and the ball portion is electrically connected to the surface metal film. The semiconductor device according to claim 1,
The semiconductor device, wherein the pad electrode is an aluminum-based pad electrode, the surface metal film is a gold-based metal film, and the metal wire is a copper-based wire. The semiconductor device according to claim 7,
The barrier metal film is a semiconductor device including at least one of titanium, chromium, titanium nitride, and tungsten nitride. The semiconductor device according to claim 8,
The seed metal film is a semiconductor device including at least one of copper, gold, nickel, platinum, rhodium, molybdenum, tungsten, chromium, tantalum, and palladium.

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