JPH04106931A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To prevent the formation of intermetallic compound by installing bumps mainly made of zinc in a semiconductor device where an electrode consists of a conductor layer whose main component is aluminum. CONSTITUTION:A conductive film is deposited on a glass-made insulation board 11, and processed into a wiring pattern so as to form a board electrode 12. Bumps 13 made of zinc whose grain size ranges from 20 to 30mum, are laid out on this board electrode 12. The bumps 13 are aligned so as to correspond to device electrodes 15 made of aluminum and installed in a semiconductor device 14 and heated under pressure from the side of the semiconductor device 14, and the semiconductor device 14 is facedown-connected with the insulation board 11. This construction makes it possible to prevent the formation of intermetallic compounds near the junctions of the device electrode 1 and the bumps 13 and hence to protect connections from defects caused by burnout.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a semiconductor device in which an insulating substrate and a semiconductor element are connected via bumps, and a method for manufacturing the same.

(Conventional technology) In recent years, with advances in semiconductor integrated circuit technology, the number of terminals has decreased from 10 to 10.
Semiconductor devices with a pad pitch of more than 0 and semiconductor devices with a pad pitch of 100 μm or less are emerging. Along with this, in order to increase the packaging density of semiconductor elements, the flip-chip method, beam lead method, tape carrier, etc., which can be bonded at once without depending on the number of electrodes during assembly, and can make chip mounting in an extremely small volume, are used. Wireless bonding is attracting attention. In particular, the flip-chip method is expected to have stronger bonding strength and higher reliability than other methods.

FIG. 6 shows an example of a conventional semiconductor device using the flip-chip method. In this method, a metal protrusion called a bump 5 is formed on the electrode 2 on the semiconductor element 1 side or the electrode 4 on the substrate 3 side, and the semiconductor element 1 is directly connected face-down to the substrate 3 via the bump 5. It is connected to.

To form the hump 5, for example, first, as shown in FIG. 7 (Ca), on the surface of the electrode 4 made of aluminum provided on the substrate 3, as shown in FIG. The metal film 6 is coated, and then, as shown in FIG. The hump 5 is immersed in an aqueous solution containing metal ions, used as a cathode, and a direct current is passed between it and the anode to electrolytically deposit metal ions at the opening as shown in FIG. 5(d). Finally, unnecessary photoresist and metal film 6 are removed to complete bump 2, as shown in FIG. 2(e).

However, with this method, there is a problem in that the gold or copper used as the bump material reacts with the aluminum of the electrode material to form a brittle intermetallic compound, which may cause inconveniences such as wire breakage.

Therefore, when forming a gold or copper hump on the electrode 4, a barrier metal layer is provided on the electrode 4, and then the same process as shown in FIGS. 6(b) to 6(e) described above is performed. A method of forming the hump 5 through a process of several steps has been adopted.

In the second method, a barrier metal layer is inserted between gold and aluminum and between copper and aluminum, so the electrode 4
Direct contact with the metal or copper hump will prevent wire breakage from occurring. However, in this method, it is necessary to form a barrier metal layer on the electrode 4, which complicates the manufacturing process, resulting in a new problem of lowering productivity.

(Problems to be Solved by the Invention) As mentioned above, in the conventional bump forming method, aluminum, which serves as an electrode, and metals, such as gold or copper, which serve as a hump, are directly bonded. A compound is formed, and as a result, the wiring becomes brittle and more likely to break, resulting in a problem of lower reliability. Also,
In order to prevent the formation of intermetallic compounds, there is a method of electrically bonding the electrode and the comb through a barrier metal, but this requires an additional step to form the barrier metal, so the entire manufacturing process is There was a problem that it became complicated and productivity decreased.

The present invention has been made in consideration of the above circumstances, and its purpose is to avoid complicating the manufacturing process.
An object of the present invention is to provide a semiconductor device and a method for manufacturing the same that can prevent the formation of intermetallic compounds.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the semiconductor device of the present invention has the following features:
In a semiconductor device comprising an electrode on an insulating substrate and an electrode on a semiconductor element connected via a bump, and an electrode of at least one of the insulating substrate or the semiconductor element or a conductive layer mainly composed of aluminum, zinc It is characterized by having a bump whose main component is.

Further, in the method for manufacturing a semiconductor device of the present invention, an electrode on an insulating substrate and an electrode on a semiconductor element are connected via a bump, and at least one electrode of the insulating substrate or the semiconductor element is made mainly of aluminum. The semiconductor device is characterized in that the bump is formed by replacing the aluminum of the electrode with zinc.

Further, it is desirable that the aluminum be replaced with the zinc by electroless plating.

Further, it is preferable that the conductor layer containing aluminum as a main component is an alloy layer consisting of aluminum and silicon.

(Function) According to the semiconductor device of the present invention, since zinc, which does not form a brittle intermetallic compound even when bonded to aluminum, is used as the hump material, the bonding condition between the aluminum electrode and the bump is improved. Since disconnections and the like are less likely to occur, the reliability is higher than that of conventional semiconductor devices.

Furthermore, according to the method for manufacturing a semiconductor device of the present invention, the aluminum in the hump forming region is replaced with zinc to form the bump. Unlike the formation of humps by forcing the zinc onto an area, the zinc precipitates spontaneously, resulting in bumps that combine dense structures. As a result, the strength of the bumps increases and corrosion at the joints becomes less likely to occur, thereby increasing the reliability of the device.

Furthermore, when aluminum is replaced with zinc using electroless plating, the aluminum grows in a lump rather than a film, so a hump can be easily formed.

Further, when an alloy layer made of aluminum and zinc is used as an electrode, silicon in the aluminum is precipitated by annealing treatment, and this silicon becomes a precipitation nucleus of plating, and zinc is easily precipitated.

(Example) A first embodiment of the present invention will be described with reference to FIG.

To explain this according to the manufacturing process, first, Corning 7
A thickness of approximately 150 mm on an insulating base number 11 made of 059 glass
0 I T O (lnclium Tin Oxid
A conductive film such as e) is deposited, and this conductive film is processed into a wiring pattern to form the substrate electrode 12. This substrate electrode 12
Bump 1 made of zinc pieces with a particle size of about 20 to 30 μm on the top
3, the bumps 13 are aligned with the element electrodes 15 made of aluminum provided on the semiconductor element 14, and heated and pressurized from the semiconductor element 14 side, and the semiconductor element 14 and the insulating substrate 11 are placed face down. Connect with.

In order for the electrode 15 made of aluminum to connect with other metals with good reliability, it is necessary to use a metal that is difficult to interdiffuse with aluminum or a metal that does not form an intermetallic compound even if it reacts with aluminum. Zinc does not form intermetallic compounds with aluminum, as can be seen from the l-2n6 full phase diagram shown in FIG.

Therefore, since zinc pieces are used as the bump material in a semiconductor device having such a configuration, no intermetallic compound is formed near the bonding surface between the element electrode 15 and the bump 13, and connection failures such as wire breakage can be prevented. The connection state between the substrate 11 and the semiconductor element 14 is improved, and a highly reliable semiconductor device can be obtained.

Next, a second embodiment of the present invention will be described with reference to FIG.

To explain this according to the manufacturing process, first, the semiconductor element 1
An aluminum alloy layer is deposited on the fourth side, and the second aluminum alloy layer is patterned to form the element electrode 25. Next, the aluminum oxide film on the device electrode 25 was removed using dilute acid, and then Substar Zn from Okuda Pharmaceutical Industries, Ltd.
-1 is used as a zinc electroless plating solution, the semiconductor element 24 on which the element electrode 25 is formed is immersed in this plating solution, and a zinc block with a thickness of about 20 to 30 μm is placed on the element electrode 25 from the surface. Bumps 23 are formed. - On the other hand, an aluminum film having a thickness of about 100 mm is deposited on a glazed aluminum substrate 21, and this aluminum film is processed into a wiring pattern to form a substrate electrode 22. Finally, as in the first embodiment, heat and pressure are applied from the semiconductor element 24 side, and the semiconductor element 24 and the insulating substrate 21 are connected face down to complete the semiconductor device.

In semiconductor devices manufactured in this way, unlike electroplating, which forcibly attracts metal ions to the bump formation area to form bumps, electroless plating is used to remove aluminum from zinc. Since zinc is substituted with zinc to form a zinc lump, bumps 23 having a very dense structure can be obtained. As a result, the bump 23 and the element electrode 2
The bonding condition with 2 is improved, corrosion etc. are less likely to occur, and the reliability of the device is increased.

Further, as a result of intensive research by the inventors, it has been found that when electroless plating is used to replace aluminum with zinc, zinc does not grow in a film shape but in a block shape. Therefore, a zinc lump that can be used as the bump 23 can be easily formed through a simple manufacturing process.

Further, as in the first embodiment, no intermetallic compound is formed near the bonding surface between the element electrode 25 made of an aluminum alloy layer and the bump 23, and it goes without saying that the reliability of the device is increased. .

Next, a third embodiment of the present invention will be described with reference to FIG.

To explain this according to the manufacturing process, first, a Ω-5i alloy film having a thickness of about 1 μm is deposited on the glazed alumina substrate 31, and this alloy film is etched to form the substrate electrode 32. Next, a silicon oxide film having a thickness of about 1,000 layers is deposited on the substrate electrode 32 to serve as a passivation film 36, and the passivation film 36 is removed so that only the portion of the substrate electrode 32 that will become the bump formation region is exposed. Next, after annealing the passivation film 36, the glazed alumina substrate 31 is immersed in a zinc electroless plating solution such as Substar Zn-1 manufactured by Shinen Pharmaceutical Industries, Ltd., so that the substrate electrode 32 is exposed. A lump of zinc is deposited in the hump forming area to form a bump 33. Finally, the element electrodes 35 and bumps 33 are aligned, and the semiconductor element 34 is connected face down to the insulating substrate 31 to complete the semiconductor device.

The semiconductor device manufactured in this way can of course obtain the same effects as the second embodiment described above.
Since an A11-Si alloy film was used as the electrode + electrode material of the substrate electrode 32, the silicon in the aluminum precipitates during the subsequent annealing process, and this silicon becomes a plating nucleus, making it easier for zinc to precipitate in the hump forming area. This makes it possible to shorten the hump formation time.

Next, referring to FIG. 5, a fourth embodiment of the present invention will be explained according to the manufacturing process. First, a semiconductor element 4
An Al-8i-Cu alloy layer is deposited on 4, and this alloy layer is etched to form device electrodes 45 in a predetermined pattern. Next, this semiconductor element 44 is immersed in a zinc electroless plating solution of Substar Zn-1 manufactured by Shinen Pharmaceutical Industries Co., Ltd. for about 60 seconds, and is coated on the element electrode 45 from the surface to a thickness of about 201 mm. ! Forms a zinc lump of about m. Next, this semiconductor element 44 was taken out of the zinc electroless plating solution, and immersed for about 5 minutes in a nickel electroless plating solution of Top Chemialloy B-1 manufactured by Shinen Pharmaceutical Industries, Ltd. maintained at 60°C. Approximately 1μ thick on the surface of the lump
The bumps 43 are formed by covering the nickel film 46 with a thickness of about m. Finally, the element electrode 45 and the substrate electrode 42 are aligned, and the semiconductor element 44 is heated and pressurized and connected face down to the insulating substrate 41 to complete the semiconductor device.

Of course, the semiconductor device manufactured in this way can obtain the same effects as the third embodiment described above.
Since the zinc lump serving as the bump material is coated with a nickel film, corrosion resistance is increased and a more reliable semiconductor device can be obtained.

Note that the present invention is not limited to the embodiments described above. For example, in the third embodiment, nickel was used to coat the zinc lump, but the coating metal may be a metal other than nickel as long as it can improve the corrosion resistance of zinc and can be formed by electroless plating. But that's fine.

Furthermore, in the above four embodiments, a semiconductor device in which either the electrode of the substrate or the semiconductor element is made of aluminum as a main component has been described; can also be applied.

Furthermore, although all of the above fourth embodiments have been described with respect to the flip-chip method, the present invention can be applied to other methods of connecting a semiconductor element and a substrate using humps, such as the TAB method. In addition, without departing from the gist of the present invention,
It can be implemented with various modifications.

U Effects of the Invention] According to the semiconductor device of the present invention, a small number of bases or semiconductor elements (one of which has aluminum as its main component) can be connected to each other through a hump whose main component is zinc. Since they are connected, the bump and the electrode mainly composed of aluminum do not form a brittle intermetallic compound. Therefore, the bonding state between the electrodes is improved, and a highly reliable semiconductor device can be obtained.

According to the method for manufacturing a semiconductor device of the present invention, bumps are formed by replacing aluminum with zinc, so the structure of the bumps becomes very dense, improving corrosion resistance,
A highly reliable semiconductor device can be obtained.

Furthermore, since the hump is corrugated with a metal with excellent corrosion resistance such as nickel, the reliability of the hump is improved.

Furthermore, by replacing aluminum with zinc using electroless plating, a lump of zinc that can be used as a hump can be easily formed.

Furthermore, since the electrode is formed of an alloy layer made of aluminum and silicon, silicon can be used as a plating layer by annealing, and the time required to form the hump can be shortened.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining a semiconductor device according to a first embodiment of the present invention, FIG. 2 is a state diagram of an AN-Zn alloy, and FIG. 3 is a diagram for explaining a semiconductor device according to a second embodiment of the present invention. FIG. 4 is a diagram for explaining a method for manufacturing a semiconductor device according to a third embodiment of the present invention, and FIG. 5 is a diagram for explaining a method for manufacturing a semiconductor device according to a fourth embodiment of the present invention. FIG. 6 is a diagram for explaining a method for manufacturing a semiconductor device, FIG. 6 is a diagram for explaining a conventional semiconductor device, and FIG. 7 is a diagram for explaining a conventional method for forming a hump. 11. 21,31.41...Substrate, 12,22゜3
2.42...Substrate electrode, 13,23.33.43...
Kumpu, 14, 24, 34.44... semiconductor element, 1
5.25.35.45 Element electrode, 36... Passivation film, 46... Nickel film. Applicant's representative Patent attorney Takehiko Suzue Zn's weight
tnF Zn42 drawing application, 53 drawing t4 drawing 5th figure

Claims (2)

[Claims] (1) A semiconductor in which an electrode on an insulating substrate and an electrode on a semiconductor element are connected via bumps, and at least one electrode of the insulating substrate or the semiconductor element is made of a conductive layer mainly composed of aluminum. In the device,
A semiconductor device, wherein the bump has zinc as a main component. (2) A semiconductor in which an electrode on an insulating substrate and an electrode on a semiconductor element are connected via a bump, and at least one electrode of the insulating substrate or the semiconductor element is made of a conductor layer containing aluminum as a main component. In the device,
A method of manufacturing a semiconductor device, wherein the bump is formed by replacing the aluminum of the electrode with zinc.