JPH07130793A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To confine a liquid metal to the inside of an insulation resin simultaneously with the hardening of the resin, by forming a metal containing Ga as its main component on one of a board electrode and a bump electrode, and by forming a metal containing one of In, Sn and Pb as its main component on the other electrode, and further, by making the liquefaction of the alloy composed of these metals start at an ordinary temperature in the interface between the two contacted electrodes, i.e., these contacted metals. CONSTITUTION:A metal 13 containing Ga as its main component is formed selectively on a board electrode 12 by a depositing or plating method, etc. Further, a metal 16 containing In as its main component is formed on a bump electrode 15 by its plating, depositing or transcribing, etc. Then, the board electrode 12 and the bump electrode 15 are so aligned with each other that they are contacted with each other, and thereafter, the electrode 15 is pressed down on the electrode 12 by a pressure collet 19. In this way, the metal 13 containing Ga as its main component and the metal 15 containing In, Sn or Pb as its main component are pressure-contacted with each other, and an alloy is formed out of them on their contact surface while its liquefaction is started at an ordinary temperature, and thereby, a liquid metal 18 is formed. At this time, the periphery of the liquid metal 18 is already confined to the inside of a hardened insulation resin 17, and the movement of the liquid metal 18 is restricted, and thereby, the contacting of the liquid metal 18 with another electrode is avoided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flip-chip mounted semiconductor chip, in which bump-formed semiconductor chips are mounted face-down, particularly on an insulating substrate through an insulating resin that is cured by light or heat energy or both. The present invention relates to a device and a manufacturing method thereof.

[0002]

2. Description of the Related Art One of the techniques for mounting a semiconductor chip on an insulating substrate is a flip chip mounting technique. In flip-chip mounting, stress is generated in the connection between both electrodes of the semiconductor and the insulating substrate due to the difference in the thermal expansion coefficient between the semiconductor chip and the insulating substrate, and the repeated stress causes fatigue in the connection and destruction. . As means for solving this problem, Japanese Patent Laid-Open No. 3-156940 proposes to connect the semiconductor electrode and the insulating substrate electrode via a metal that becomes liquid in the operating temperature range of the semiconductor element. FIG. 2 shows a sectional view of this semiconductor device. A substrate electrode 22 is formed of a resin such as ceramic or polyimide that forms the insulating substrate 21. The substrate electrode 22 is made of Au or Cu, and its surface is plated with In or Sn. Si chip 23
On the surface of, the bumps 24 plated with In or Sn on Au or Cu are formed, and Ga 25, which becomes a liquid in the semiconductor element operating temperature range, is accumulated on the substrate electrode 22. In this state, the Si chip 23 is placed facedown on the insulating substrate 21 and the electrodes 22 and 23 are connected.

[0003]

However, in the mounting technique as described above, it is necessary to fix the semiconductor chip to the insulating substrate by another means. Therefore, Japanese Patent Laid-Open No. 2-246130 proposes fixing by soldering. However, when a metal that is liquid in the semiconductor operating temperature range is used for connection, for example, when the substrate is tilted, there is a risk of contact with other electrodes due to fluidity, so electrodes with a narrow pitch are used. There was a problem, however. Further, even when the semiconductor chip is filled with the insulating resin as another fixing means, the substrate cannot be tilted, so that it is necessary to be very careful. In addition, Ga that easily becomes liquid
In order to form a metal on an electrode, when an inexpensive forming method such as printing or transfer in a paste form is used, it is easily liquefied, which requires temperature control in the forming process.

[0004]

In order to solve the above problems, the present invention provides a semiconductor chip having a bump electrode formed on the surface thereof, or light or heat energy on an insulating substrate having an electrode formed on the surface thereof. In a mounting structure of a semiconductor chip in which an insulating resin that is cured by both is applied and then the electrodes are contacted face down to cure the insulating resin while applying pressure, an electrode formed on an insulating substrate or formed on the semiconductor chip. A metal containing Ga as a main component is formed on one of the bump electrodes, and a metal containing any of In, Sn, and Pb as a main component is formed on the other electrode, and the contacted Ga is removed. Metal as main component and above I
It is used that a metal containing any one of n, Sn and Pb as a main component forms an alloy at room temperature to become a liquid.

A paste containing a metal mainly containing microcapsules, which is microencapsulated, is formed by a printing method or a transfer method on an electrode formed on an insulating substrate or a bump electrode formed on a semiconductor chip. On the other hand, a metal containing In, Sn, or Pb as a main component is formed by a plating method or a vapor deposition method. A method of manufacturing a semiconductor device is used in which a metal containing the above as a main component forms an alloy at room temperature to form a liquid.

[0006]

A metal containing Ga as a main component is present on either an electrode formed on an insulating substrate or a bump electrode formed on a semiconductor chip and the other contains In, Sn, or Pb as a main component. Form metal. At this time, Ga is about 30
Since it has a melting point of .degree. C., it is solid if the mounting work atmosphere for semiconductors is kept at room temperature of about 25.degree. Further, the metal containing In, Sn, and Pb as the main components formed on the other electrode is naturally solid at room temperature. In this state, even after the insulating resin which is cured by light or heat energy or both is applied onto the substrate, the respective electrodes can be pushed away and brought into contact with each other. Further, after being contacted with each other, it becomes liquid at room temperature from the interface between the metal containing Ga as a main component and the metal containing any of In, Sn and Pb as a main component. It can be enclosed in resin.

Further, a metal containing Ga as a main component can be formed into a paste by microencapsulation, and even by an inexpensive method such as printing, the temperature can be easily controlled in the forming process, so that the manufacturing cost is low. it can.

[0008]

EXAMPLE A semiconductor device according to an example of the present invention will be described below.
A description will be given with reference to the drawings.

FIG. 1 is a sectional view of a semiconductor device according to the first embodiment of the present invention, in which an Au film is formed on an insulating substrate 11.
Alternatively, the substrate electrode 1 made of a metal such as Ag or Ag-Pt 1
2 is formed by thick film printing or photolithography of a deposited thin film. On such a substrate electrode, a metal 13 containing Ga as a main component is selectively formed by vapor deposition or plating. In the case of vapor deposition, the substrate electrode 12 and G
The metal 13 containing a as a main component may be simultaneously formed and patterned. On the other hand, as an example of a semiconductor element such as an IC such as Si or GaAs, an LSI or a III-V group optical semiconductor such as an LED or LD, the SiIC chip 14 has a bump formed by Au plating on Au or another metal, or alternatively Au. The bump electrode 15 made of solder metal is formed by a plating method or a wire bump using a wire bonder. Further, a metal 16 containing In as a main component is formed on the bump by means of plating, vapor deposition, transfer or the like. At this time, the ratio of In, Sn or Pb to Ga is 2 to 2
It is desirable to adjust the thickness to be 0 atm%. At this time, the metal 13 whose main component is Ga is solid. Next, such a semiconductor element 14 is diced into a mounting form and mounted on the insulating substrate 11 using a mounting machine. In the mounting machine, the photocurable insulating resin 17 is applied to a predetermined mounting position on the insulating substrate 11 by using a stamping method or a dispenser or the like, and the substrate electrode 12 and the semiconductor bump electrode 1 are applied.
Position so that 5 abuts and apply pressure with collet 19. The pressure applied at this time is preferably in the range of 0.1 to 0.3 kg per bump electrode. If the insulating substrate is a transparent substrate such as glass, the resin is cured by irradiation with UV light 10 from the back surface different from the mounting surface of the substrate,
The mounting is then completed by releasing the pressure. At this time, the solid metal 13 and I containing Ga as a main component and I
The metal 16 containing n, Sn, or Pb as a main component is brought into contact with each other by pressurization, and an alloy is formed from the contact surface at room temperature to start liquefaction and form a liquid metal 18. At this time, the surroundings are already enclosed by the hardening of the insulating resin 17, and the movement of the liquid metal 18 is restricted, so that contact with other electrodes is avoided. Further, here, the result is the same even if the metal 13 and the metal 16 are located at opposite positions. According to this method, 30 μm
Even with a narrow pitch, there was no contact between the electrodes and mounting was possible. Further, even though the thermal expansion coefficient of the glass substrate and that of the SiIC chip were three times different, they were stable even in a thermal shock test of 2000 cycles by holding each at -30 ° C to 70 ° C for 30 minutes.

Next, a case of an opaque substrate will be described as a second embodiment. In the same manner as in Example 1, an insulating substrate 11 such as an alumina substrate, a glass epoxy substrate or an organic material substrate such as polyimide, a SiIC chip 14 which is a semiconductor element, a substrate electrode 12, a metal 13 containing Ga as a main component, and a bump electrode 15, respectively. A metal 16 containing In, Sn or Pb as a main component is formed. Next, similarly, such a semiconductor element 14 is diced into a mounting form and mounted on the insulating substrate 11 using a mounting machine. In the mounting machine, the photothermal combined curing type insulating resin 17 is applied to a predetermined mounting position of the insulating substrate 11 by using a stamping method or a dispenser, and the substrate electrode 12 and the semiconductor bump electrode 15 are positioned and added so as to contact each other. Apply pressure. The resin on the side surface of the semiconductor element 14 is cured by light irradiation from the mounting surface of the substrate, and then the pressure is released. Further, the mounting is completed by raising the temperature of the entire substrate to the resin curing temperature while keeping it horizontal.

Also in this case, the metal 13 and the metal 16 form an alloy at the abutting portion due to contact and temperature rise, and become liquid metal. Further, the periphery is enclosed by the curing of the insulating resin 17, and the movement of the liquid metal is restricted, so that contact with other electrodes is avoided after the curing. Further, here, the results are the same even if the metal 13 and the metal 16 are located at opposite positions. In this case as well, the glass epoxy substrate and the SiIC chip were stable in the thermal shock test even though there was a 10-fold difference in the coefficient of thermal expansion. This is because the liquid absorbs thermal strain at constant temperature due to the connection by the alloy which becomes liquid at 17 ° C. or higher.

Next, as a third embodiment, an example using metal particles microencapsulated as a method of forming a metal containing Ga as a main component will be described. The metal containing Ga as a main component is liquefied at a temperature of about 30 ° C. For encapsulation, a metal containing Ga as a main component is placed in one or more good solvents in which the shell material is dissolved, and the temperature is raised to 30 ° C. or higher to melt the metal. The dissolved metal is dispersed in a good solvent with stirring (or ultrasonic waves may be added) or while filtering the metal with a fine mesh to a particle size of about 5 to 50 μm. Next, by gradually adding the poor solvent, the metal containing Ga as a main component can be easily encapsulated. The encapsulated metal particles are stably maintained even when the temperature rises above the liquefaction temperature, and can be easily made into a paint by dispersing them in a printing paste or an adhesive. By using such a printing paste or paint, printing on a substrate electrode or transfer to a semiconductor bump electrode enables efficient and inexpensive formation.
If the metal containing Ga as a main component formed on the substrate electrode or the semiconductor bump electrode is destroyed in advance by heat or pressure and the metal containing Ga as a main component is directly formed on the electrode, the capsule may be easily mounted during mounting. It is possible to keep the dispersion small. When the printing method is used, the mounting pitch is defined by the accuracy of printing, and the pitch of 150 μm is at a practical level.

[0013]

According to the semiconductor device and the method of manufacturing the same of the present embodiment, it is possible to provide a semiconductor device having sufficient resistance to a thermal shock test even for a substrate and a semiconductor element having a narrow pitch of 30 μm and having a significantly different thermal expansion coefficient. This makes it possible to use an inexpensive substrate material. In addition, by encapsulating a metal containing Ga as a main component in a microcapsule, a printing method, a stable transfer method, or the like can be used and can be provided at low cost.

[Brief description of drawings]

FIG. 1 is a sectional view of a semiconductor device according to a first embodiment.

FIG. 2 is a sectional view of a conventional semiconductor device.

[Explanation of symbols]

 Reference Signs List 10 UV light 11 Insulating substrate 12 Substrate electrode 13 Metal containing Ga as a main component 14 SiIC chip 15 Bump electrode 16 Metal containing In as a main component 17 Photocurable insulating resin 18 Liquid metal 19 Pressurizing collet 21 Insulating substrate 22 Substrate electrode 23 Si chip 24 Bump 25 Ga

Claims (2)

[Claims] 1. A semiconductor chip having bump electrodes formed on its surface is coated on an insulating substrate having electrodes formed on its surface with an insulating resin which is cured by light or thermal energy or both, and the electrodes are face down. In a semiconductor chip mounting structure in which the insulating resin is cured while contacting and pressurizing, a metal containing Ga as a main component is applied to either an electrode formed on an insulating substrate or a bump electrode formed on the semiconductor chip. The above-mentioned G formed on the other electrode is contacted with a metal containing In, Sn, or Pb as a main component.
A semiconductor device, wherein both a metal containing a as a main component and a metal containing any of In, Sn and Pb as a main component form an alloy at room temperature to become a liquid. 2. A semiconductor chip having bump electrodes formed on its surface is coated on an insulating substrate having electrodes formed on its surface with an insulating resin which is cured by light or thermal energy or both, and the electrodes are face down. In a semiconductor chip mounting structure in which the insulating resin is cured while contacting and pressurizing, mainly Ga micro-encapsulated on either an electrode formed on an insulating substrate or a bump electrode formed on the semiconductor chip is used. A paste mainly composed of metal as a component is formed by a printing method or transfer, and In, S
A metal containing n or Pb as a main component is formed by a plating method or a vapor deposition method, and is brought into contact with the metal containing a main component of Ga and a metal containing any of In, Sn or Pb as a main component. A method for manufacturing a semiconductor device, wherein and form an alloy at room temperature to become a liquid.