JPH0150100B2 - - Google Patents

Description

[Detailed Description of the Invention] The connection methods for semiconductor chips mounted on hybrid integrated circuits include die bonding using eutectic alloys, solders, conductive adhesives, etc., wire bonding in which Al and Au wires are bonded by thermocompression bonding, and die bonding using thermocompression bonding. As shown in Figure 1, so-called face-down bonding is known, in which the electrodes of the chip 1 are raised to form bump electrodes 2, and the electrodes 2 are connected directly to the conductor pattern 4 of the substrate 3 by overlapping them. The present invention relates to a hybrid integrated circuit using face-down bonding type elements (hereinafter referred to as flip chips) which have recently been widely used in automotive electronic circuits and the like.

Conventionally, when mounting a flip chip on a board, since the connection part is on the back side of the chip, a half mirror 5 is placed between the chip 1 and the board 3 for alignment during mounting, as shown in FIG. put
A method has been widely used in which the image of the lower surface of the chip reflected by the half mirror 5 and the image of the circuit board surface transmitted through the half mirror 5 are overlapped to make an observation.

However, this method has problems in that it is difficult to automate, increases the number of assembly steps, and causes misalignment between the electrodes of the element and the conductor pattern on the substrate, which have extremely small intervals.

The present invention was developed in view of the situation where automatic positioning has become possible due to recent improvements in pattern recognition technology.When forming preliminary solder for hybrid integrated circuits, waste solder that is not used for wiring is transferred to the element mounting area. By forming alignment marks on the outer conductor pattern using the same mask and forming alignment marks together with the background material, it is possible to achieve highly accurate alignment and mounting through automation without increasing assembly man-hours.

Embodiments of the present invention will be described below based on a partial plan view in FIG. 3 and a partial longitudinal sectional view in FIG. 4. A conductor pattern 7 is printed and fired on the ceramic substrate 6, and this pattern 7 constitutes a group of leads to be connected to the flip chip. A bump-receiving solder 8 as a preliminary solder is applied at a position corresponding to the bump (electrode) of the chip in the flip-chip mounting area of the conductor pattern 7 (indicated by a dashed-dotted line in FIG. 3) by a printing method using a metal mask. It is formed. In this embodiment, with such a configuration, the alignment mark is a waste solder 9 surrounded by a fired body of resistance paste.

This waste solder 9 is used when forming bump receiving solder 8 by a printing method using a metal mask.
It is formed by providing an opening in a metal mask on the conductor pattern outside the flip chip mounting area. On the other hand, the fired body 10 of the resistance paste is
At the time of resistance printing firing before the waste solder 9 is formed, it is formed at a position surrounding the waste solder 9, leaving a part where the waste solder 9 is formed in the center.

Generally, solder is silver-based in color, and fired resistors are black in color. Therefore, this positioning mark, in which the fired resistor paste 10 forms the background of the discarded solder 9, is used as a position detection signal for automatic positioning. Adequate stability can be obtained as a source of

In addition, when configuring a hybrid integrated circuit, applying the sandblasting method used when correcting the resistance value to the fired resistor paste 10 and polishing it by scraping off the surface film will improve the binary signal of the mark. It is preferable in the sense that it makes it more extreme.

In addition, in this embodiment, the resistors and solder as alignment marks can be formed simultaneously in the resistor printing/baking process and the pre-solder application process, which are performed when constructing a hybrid integrated circuit. There is no need to worry about the increase in man-hours.

Furthermore, the automatic mounting positioning for positioning the semiconductor chip at a fixed position on the board according to the present invention means placing two or more positioning marks in advance at set positions on the board and fixing the marks. Imaging means at the location (e.g. ITV camera, etc.)
The amount of movement of the head that picks up the semiconductor chip is determined by calculation from the difference between the detected mark and a preset position.

Therefore, the positional relationship between the alignment marks set on the substrate and the mounting area of the semiconductor chip must be memorized in memory at the design stage, especially when the electrode spacing is as small as several 100 μm. When mounting flip chips, the accuracy of this positional relationship is important. For example, if the positional relationship between the reference position and the alignment mark in the mounting area is set and then these are formed separately, highly accurate alignment cannot be achieved. In this regard, according to the present invention, the reference position is made of bump-receiving solder, the alignment mark is made of waste solder, and these are simultaneously formed using the same metal mask, so alignment and mounting can be performed with extremely high accuracy. Can be done.

In the above embodiment, the background material surrounding the discarded solder is a fired resistor paste, but the present invention is not limited to this. For example, the background material may be formed as a protective coating film after firing the resistor paste. It may also be a fired product of glass paste.
Even in this case, it is important that the glass paste is fired at the same time as the glass printing and firing process before forming the solder.

Furthermore, if shortening of the manufacturing process is not particularly required, the background material surrounding the discarded solder does not need to be a component for forming a hybrid integrated circuit as described in the above embodiment, and it is not necessary to Any paint or adhesive that has a strong contrast with the solder may be used as long as a binary signal can be obtained.

The present invention is particularly effective when positioning and mounting flip chips, but it goes without saying that it is also applicable to any method in which preliminary solder is formed in advance for chip connection.

As is clear from the above description, according to the present invention, during preliminary soldering of a hybrid integrated circuit, discarded solder is formed on the conductor pattern outside the element mounting area using the same mask, and the positioning mark is formed together with the background material. Highly accurate positioning and mounting can be achieved through automation without increasing assembly man-hours.

[Brief explanation of drawings]

FIG. 1 is a side view showing a face-down structure, FIG. 2 is a schematic diagram showing a conventional positioning mechanism in a face-down bonder, and FIGS. 3 and 4 are partial plan views showing an embodiment of the present invention. and a partial longitudinal sectional view. 6: Ceramic substrate, 7: Conductor pattern, 8:
Solder for bump receiving, 9: Waste solder, 10: Sintered body of resistance paste.

Claims (1)

[Claims] 1. In a device in which a semiconductor chip is mounted on a substrate by optically detecting an alignment mark set on a substrate, the alignment mark is formed by the same mask as the preliminary solder. , a hybrid integrated circuit characterized in that it is made of discarded solder with a background material surrounding it. 2. In what is stated in claim 1,
A hybrid integrated circuit characterized in that the background material is a fired body of resistance paste. 3 In what is stated in claim 1,
A hybrid integrated circuit characterized in that the background material is a fired body of glass paste.