JPH0374816A - Chip parts and their mounting method - Google Patents

Abstract

PURPOSE:To improve tbe precision of position and posture even in the oase of a microminiature chip parts, and reduoe the area occupied by adhesive agent to a minimum, by forming a dry to tbe toucb resin ttlm at the bonding part of the chip parts with a terminal part or a circuit board. CONSTITUTION:An alumina board 5, e.g. for a hybrid IC use, on which surface a plurality of pads 6 are arranged is fixed on a stand having a heater 7, and preliminarily beated at 100-110 deg.C. Electrodes arranged on both sides of the chip 1 are mounted on two pads 6, and welded with pressure to be fixed on the pads 6. At this time, the electrodes bave been coated with a conduotive epoxy resin film 3 in the state of dry tac. The resin 3 sbows autohesion prcperty at 100-110 deg.C, and preliminary fixation of sufficient strength is enabled. After that the board 5 is put in a thermostatic chamber, and heated at 160 deg.C for 60 minutes to complete the bardening. Hence the mounting of a microminiature chip parts is faoilitated, and the reliability is improved.

Description

[Detailed Description of the Invention] [Summary] Regarding semiconductor devices, more specifically, chip components and their mounting methods, when mounting ultra-small chip components, it is possible to improve the accuracy of the position and orientation of the components, and to improve the adhesiveness of the components. In order to minimize the area occupied by the agent, a resin film that is dry to the touch is formed on the surface of the terminal part of the chip component or the adhesive part with the circuit board, and the bracket part is attached to the preheated circuit board. The structure is such that it is mounted on top, temporarily fixed, and then fully cured.

[Industrial application field]

The present invention relates to a semiconductor device, and more particularly to a chip component and a method for mounting the same.

[Conventional technology]

To mount chip components on a circuit board, usually cream solder is printed on the board, the chip components are mounted, and the components are bonded by reflow heating. Solder has a high surface tension, so
It has the advantage of being able to limit the adhesive area, but on the other hand, it is 1.6
X 0. In the case of ultra-small chip parts of Bam size, the so-called "Manhattan phenomenon" occurs and the parts become inverted. To avoid this, it is necessary to strictly control the amount of cream solder printed at the position of each chip component on the board, which is a bottleneck in the mass production process. It is also necessary that the terminal portion or adhesive portion of the chip component be formed of a solderable metal. Furthermore, in the case of a hybrid IC, since paired chip components are mounted at the same time, a process of locally applying a resin is required to protect the IC from flux cleaning residue that accompanies soldering.

In order to avoid this, as an alternative to soldering mounting, a resin adhesive is applied by printing or transfer to the position of each chip component on the board, and the chip component is mounted on this. In this case, unlike solder, the adhesive area expands, so if the amount of resin is too large, a short circuit will occur between the terminals, especially if a conductive adhesive is used. Therefore, it is necessary to strictly control the amount of resin between the minimum possible amount necessary to maintain strength and the maximum allowable amount to prevent expansion of the bonding area, which is the range of optimal conditions especially for mounting ultra-small chip components. This was a difficult problem in manufacturing.

[Problem to be solved by the invention]

An object of the present invention is to eliminate the drawbacks of the above-mentioned chip component mounting methods, and to provide a chip component that has a desired amount of resin coated accurately and is easy to handle, and a mounting method thereof. .

[Means to solve the problem]

The above problem involves a chip component in which a touch-dry resin film is formed on the surface of the terminal part of the chip component or the adhesive part with the board, and this chip component is mounted on a preheated circuit board and temporarily fixed. However, this problem can be solved by a mounting method in which the problem is cured after that.

[For production]

Chip components may be passive elements such as resistances, capacitances and reactances, or active elements such as field effect transistors, or conductive members such as chip jumpers. The type of resin used may be thermosetting or thermoplastic.The thermosetting resin is applied to the chip component in a B-stage state containing a volatile solvent, and the solvent is evaporated to make it easy to handle. Dry to the touch (B stage).

On the other hand, the substrate is preheated to an appropriate temperature, and a chip component to which a touch-dry thermosetting resin is adhered is pressed onto a predetermined position on the substrate to temporarily fix it.

The temperature of the substrate is raised to harden the resin. The resin layer attached to the chip component is made thin in advance to about 50 to 100 mm, so that the contact area does not expand and short circuits do not occur even in the case of conductive resin.

Further, the component to which the thermoplastic resin is attached may be temporarily fixed by pressure bonding onto a heated substrate, and then cooled to room temperature and cured. However, if the semiconductor device particularly requires heat resistance, thermosetting resins are advantageous.

〔Example〕

FIG. 1 shows an embodiment of the chip component of the present invention.

Here, we use 1.6 x 0.8 to evaluate the connection status.
Use w size chip jumper 1, terminal electrode 2 is A
It was formed from g-Pd. This terminal electrode is coated with a conductive epoxy resin 3 that is dry to the touch.

For the coating, commercially available B-stage conductive epoxy resin 4 (Ag powder, a heat-resistant epoxy resin base, and a curing agent were mixed with a volatile solvent to a viscosity of io, ooo to 20,000 cps).
(adjusted to) was used. As shown in Figure 2, the coating method is to uniformly coat this resin into a groove with a depth of 0.3 to 0.5 mm, and then dip the terminal part 2 of the chip jumper 1 into the groove on one side at a time. , 80-100 on a Teflon plate
It was heated to 0.degree. C. to dry the volatile solvents it contained. In this way, the chip jumper after drying was in a state where the resin was dry to the touch without self-fusing properties at room temperature, making it easy to handle.

Next, an embodiment of the chip component mounting method of the present invention is shown in FIG. 3, in which an alumina substrate for a hybrid IC on which a thick film circuit pattern was formed was used as a circuit board. First, (a) on the table 7 on which this alumina circuit board 5 is fixed,
The chip jumper 1 was preheated to 0''C and then (b) the chip jumper 1 was crimped and fixed onto the mounting pad 6. The resin 3 formed on the terminal part develops self-bonding properties at 100 to 110°C and is fully bonded. (C) The circuit board on which the temporary mounting was completed was permanently cured for 60 minutes in a constant temperature bath at 160° C. The characteristics of the circuit board on which the mounting was completed are shown in Table 1.

Further, in order to evaluate the reliability of the resin connection (A) according to the present invention, a liquid phase thermal shock test was conducted on it at -55 to 125°C. Figures 4 and 5 show the impact cycle dependence of connection resistance and adhesive strength. Conventional solder connections made at the same time (B
Although the initial connection resistance is slightly higher than that of the solder connection (B), the connection resistance becomes open after 300 cycles and the adhesive strength decreases at the same <300 cycles, whereas the resin connection of the present invention ( A) was found to maintain its stability up to at least 2000 cycles.

In this embodiment, an example of an Ag--Pd thick film conductor is shown as a mounting pad, but the pad conductor is not limited to this, and can be applied to, for example, a Cu conductor in a normal printed board without any problem. Further, as another embodiment of the hybrid IC, the present invention can be applied to a thin film circuit having an Au conductor on the surface layer without any problem.

Further, the resin to be applied may be a solvent-free type, and it is of course possible to connect parts coated with a non-conductive resin to the board.

〔Effect of the invention〕

According to the present invention, ultra-small chip components can be easily and reliably mounted, and therefore the present invention is highly applicable as a mounting method for current electronic devices that are required to be light, thin, short, and small.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of a resin-coated chip component according to the present invention, FIG. 2 is an explanatory diagram of resin coating of the chip component, and FIG. 3 is an explanation of the chip component mounting method according to the present invention. FIG. 4 is a graph showing changes in connection resistance due to a thermal shock cycle test, and FIG. 5 is a graph showing changes in adhesive strength due to a thermal shock cycle test. DESCRIPTION OF SYMBOLS 1... Chip component, 2... Terminal part, 3... Resin that is dry to the touch, 4... B stage type resin, 5... Circuit board, 6... Pad, 7... ...Heater, A...Resin bonded chip component of the present invention, B...Solder connected chip component. A cross-sectional view of a resin-coated little tube part of the present invention

Claims (2)

[Claims] 1. A chip component, characterized in that a resin film that is dry to the touch is formed on the surface of a terminal portion of the chip component or a bonded portion with a circuit board. 2. A chip characterized in that a chip component having a touch-dry resin film formed on the surface of the terminal part or the adhesive part with the circuit board is mounted on a preheated circuit board, temporarily fixed, and then fully cured. How to mount parts.