JPH05144853A - Bonding method of semiconductor chip - Google Patents

Abstract

PURPOSE:To prevent a conductive adhesive agent from crawling up and getting stuck between LEDs when the LEDs are arranged in array and die-bonded. CONSTITUTION:LED chips 3 are arranged in array on a conductor pattern 2 formed on a board 1 providing a gap between them and die-bonded with conductive adhesive agent 4, where a recess 5 is formed by removing a part of the conductor pattern 2 located under the gap concerned. By this setup, the excessive part of the conductive adhesive agent 4 is made to flow into the recess 5 concerned, so that the adhesive agent is prevented from crawling up and getting stuck between the LED chips.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to LED chips and CCDs.
The present invention relates to a technique of arranging and bonding a plurality of semiconductor chips such as chips.

[0002]

2. Description of the Related Art In an LED print head, a plurality of LEs are used.
D-bond the D chip according to the required length. For example, if a length of 100 mm is required, 10
Arrange 10 mm length chips. This only needs to satisfy the required length with one chip, but it occurs due to the balance between the yield cost in chip manufacturing and the mounting cost (bonding a plurality of chips). In fact, in the case of an LED head used for an A4 size LED printer, 40 chips each having a length of about 5.4 mm are die-bonded in a row, one by one, to secure a predetermined print width.

Similarly, in the CCD image sensor, the CCD
Die-bond the chip according to the required length,
Secure a predetermined reading width. 2A and 2B are side views showing a conventional LED chip die bonding method. FIG. 2A shows a state before die bonding and FIG. 2B shows a state after die bonding. In the figure, 11 is a substrate formed of glass epoxy resin or the like, 12 is a conductor pattern (common terminal pattern) formed of copper foil or the like on the substrate 11, 13 is an LED chip, and 14 is the LED chip 13 as the conductor pattern 12. It is a conductive adhesive such as a silver paste to be adhered.

As shown in this figure, in die bonding of an LED chip, a conductive adhesive 14 is applied to a conductor pattern 12 formed on a substrate 11, and an LED chip 13 is placed thereon and pressed. I was doing it.

[0005]

However, in the conventional LED chip die-bonding method, as shown in FIGS. 3 (a) and 3 (b) in which the portion A of FIG. 2 is enlarged,
The gap between the LED chips 13 is provided only around 10 μm in order to secure the pitch of the light emitting portions 15. Therefore, at the time of die bonding, the conductive adhesive 14 protrudes between the LED chips 13 to form a pool 16 (see FIG. 3).
(A)). Further, if the chip end surface 13a has an inverse taper, it may creep up due to a capillary phenomenon, reach the chip surface, and clog the LED chips 13 (FIG. 3 (b)). Conductive adhesive 1 between the LED chips 13
When 4 is clogged, self-heating during the operation of the chip 13 or expansion / contraction stress is caused by a change in environmental temperature, which causes distortion in the PN junction of the light emitting section 15 in the vicinity, resulting in deterioration of the light amount due to deterioration of the PN junction. There was a problem.

Further, when a plurality of CCD chips are die-bonded, the light receiving portion of the image sensor is also deteriorated. Then, as a method of solving the above problems, in order to stop the supply amount of the conductive adhesive to a necessary minimum, a stamping method of supplying a constant shape and thickness like a stamp, the conductive adhesive into a small diameter dot shape. Although the multi-point method of supplying by dividing is devised, if the entire back surface of the chip is filled with a conductive adhesive, the surplus of the conductive adhesive will inevitably overflow. Conversely, if you do not fill the entire back surface of the chip, the LED
A chip having a narrow width (about 500 μm) such as a chip cannot obtain sufficient adhesive strength to withstand wire bonding and the like, and the floating and inclination of the chip affect the wire bonding conditions. Further, as shown in FIG. 4, there is an example in which the lower end portion 13b of the chip is cut to prevent the excess creeping up and clogging of the conductive adhesive, but the chip is cut out from the wafer twice. There is a problem that it must be done.

According to the present invention, in order to prevent the stress caused by the above-mentioned creeping up and clogging of the conductive adhesive, the layout of the conductor pattern is modified so that the restriction on the supply amount of the adhesive is greatly alleviated. Moreover, it is an object of the present invention to provide a die bonding method for a semiconductor chip, which can prevent the adhesive from creeping up without changing the structure of the chip and consequently prevent the deterioration of the semiconductor chip.

[0008]

In order to solve the above-mentioned problems, the present invention provides a method in which a plurality of semiconductor chips are arranged on a conductor pattern formed on a substrate with a gap therebetween and a conductive adhesive is used. In the die-bonding method, the conductor pattern under the gap is removed to form a recess, and the surplus conductive adhesive is accommodated in the recess.

[0009]

According to the present invention, since the semiconductor chip die bonding method is configured as described above, the surplus of the conductive adhesive is accommodated in the recess formed in the lower portion of the gap. Therefore, the surplus of the conductive adhesive does not crawl up the gap between the chips and does not clog the chips.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows an L according to an embodiment of the present invention.
It is an explanatory view of the die-bonding method of an ED chip, (a)
Is a side view before die bonding, (b) is a side view after die bonding, and (c) is a plan view after die bonding.

In the figure, 1 is a substrate formed of glass epoxy resin, 2 is a conductor pattern (common terminal pattern) formed on the substrate 1 with copper foil to a thickness of about 25 μm, 3 is an LED chip, and 4 is It is a conductive adhesive such as a silver paste that adheres a plurality of LED chips 3 arranged with a gap of 10 μm to the conductor pattern 2. In this embodiment, the conductor pattern 2 under the gaps between the plurality of LED chips 3 is further etched and removed to expose the substrate surface. As a result, in the lower part of the gap between the LED chips 3, the thickness of the copper foil forming the conductor pattern 2 (about 25 μm
The depression 5 of m) is formed.

In the present embodiment, the LED chip 3 is die-bonded by applying a conductive adhesive 4 to the conductor pattern 2 formed on the substrate 1 and then applying the LED chip 3 thereon.
Is placed with a gap of 10 μm and pressed. At this time, as shown in FIG. 1 (b), since the surplus of the adhesive 4 protruding from the bottom of the LED chip 3 into the gap is accommodated in the recess 5 formed in the lower part of the gap, the space between the LED chips 3 is reduced. It will not be able to crawl through the gap. When the substrate 1 is made of glass epoxy resin, the adhesive 4 itself does not easily flow (spread), so that the effect is great.

Further, in this embodiment, by making the length of the recesses 5 formed in the lower portion of the gap in the chip arrangement direction longer than the gap interval (around 10 μm), variations in die bonding position accuracy are absorbed. To prevent crawl up. Further, in this way, the capacity of the recess 5 becomes large, so that it is possible to reliably prevent the conductive adhesive 4 from creeping up. However, in this case, the back surface of the LED chip 3 jumps out to a portion where the pattern 2 is removed by etching, but the Au-based electrode formed on the back surface of the LED chip 3 causes ohmic contact between the LED chip 3 and the conductor pattern 2. Is secured.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention, which are not excluded from the scope of the present invention. The present invention can also be applied when die bonding a CCD chip or the like.

[0015]

As described above in detail, according to the present invention, when a plurality of chips are arranged with a slight gap and die-bonded, the surplus amount of the conductive adhesive is provided below the gap. Since it is accommodated in the formed recess, the following effects are achieved. (1) The conductive adhesive is prevented from creeping up between the chips and clogging. As a result, it is possible to prevent the occurrence of stress on the end of the chip by a simple method that does not require structural modification of the chip, and it is very effective in improving the reliability of the connection portion between the chip and the conductor pattern. (2) It is possible to perform die bonding including the chip without increasing the cost. (3) The restrictions on the adhesive supply amount can be significantly eased. (4) It is possible to easily cope with further narrowing of the gap between the chips.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a die bonding method for a semiconductor chip according to an embodiment of the present invention.

FIG. 2 is a side view showing a conventional LED chip die bonding method.

FIG. 3 is an enlarged view of part A of FIG.

FIG. 4 is an explanatory diagram of a processing example of a conventional LED chip.

[Explanation of symbols]

 1 substrate 2 conductor pattern 3 LED chip 4 conductive adhesive 5 recess

Claims (3)

[Claims] 1. A method of arranging a plurality of semiconductor chips on a conductor pattern formed on a substrate with a gap and die-bonding with a conductive adhesive, wherein the conductor pattern under the gap is removed. A method for die-bonding a semiconductor chip, characterized in that a recess is formed and an excess of the conductive adhesive is accommodated in the recess. 2. The method of die bonding a semiconductor chip according to claim 1, wherein the length of the recess in the chip arrangement direction is longer than the gap. 3. The method of die bonding a semiconductor chip according to claim 1, wherein the semiconductor chip is an LED chip.