JPS5921045A - Forming method for bump for connection - Google Patents

Abstract

PURPOSE:To form the high bump easily on a substrate, on which the bump is to be disposed through a lift-off method by coating a negative type resist film with an opening with a conductor layer and dissolving and removing each resist film. CONSTITUTION:A first positive type resist film 22 is applied on the substrate 21 on which a bump is to be formed, and dried and cured, and the resist film 22 is coated with a first metallic layer 23 of an element such as aluminum. The upper surface of the metallic layer 23 is coated similarly with a second positive type resist film 24 and a second metallic layer 25 of Al. The second metallic layer 25 exposed to an opening section 27 is removed selectively through etching while using a negative type resist film 26 with the opening section 27 as a mask, and the second positive type resist film 24 exposed is exposed selectively, and dissolved and removed by a developer. The surface is coated thickly with a good- conductive metallic conductor layer 29 of indium, etc. The positive type resist films 22, 24 to which the disposing hole 28 is formed are dissolved by a resist exfoliating liquid.

Description

Detailed Description of the Invention (+1) Technical Field of the Invention The present invention relates to a connection bump that can be used to mount an active element such as a semiconductor chip on a passive circuit board by a face-down bonding method and can form a long bump. This relates to a method of forming.

(b) Prior Art and Problems In general, in the assembly of hybrid ICs, etc., one method for mounting active elements such as semiconductor chips on a passive circuit board-L is to use connection terminals of the semiconductor chip or bonding of the passive circuit board. Connection of the ends or both of these,
Forming conductive bumps made of relatively soft indium (In) or the like at the bonding portions, overlapping the bump placement portions of the semiconductor chip onto the corresponding connection points of the circuit board,
Face-down bonding is known, in which the semiconductor chip is mechanically fixed on the circuit board by pressure bonding and electrically connected, and at the same time, it is possible to connect multi-corrosion contacts, and it is also possible to connect the semiconductor chip to the circuit board. It has the advantage of increasing packaging density. By the way, the bumps used in the above-mentioned face-down bonding have conventionally been formed on a substrate 1 on which the bumps are to be formed, for example, as shown in FIG.
+-1/ +7 7 1- After coating the negative photoresist film 3 on the positive photoresist film 2 with In, the substrate 1 is coated with a negative photoresist film 3. The negative photoresist film 3 and the positive photoresist film 2 on the area where bumps are to be formed are sequentially patterned into a predetermined pattern to form openings 4 as shown in FIG. A highly conductive metal layer 5 made of indium (In) or the like is deposited on the entire surface of the shaped photoresist film 8 by, for example, vapor deposition, and then each of the dinut films 2 and 8 is dissolved with a resist stripping solution. By removing the bumps 6, as shown in FIG. 3, the bumps 6 are formed as shown in FIG. The height of the bumps 6 is limited by the thickness of the resist film patterned on the substrate. Therefore, as described above, the bumps 6 are formed high by laminating two layers of a positive photoresist film 2 and a negative photoresist film on the substrate 1 on which the bumps are to be formed, but in reality, the height is 5 to 6 μm. However, it is difficult to form bumps having a height of at least 10 μm or more, which would allow suitable bump connection.

(C) Object of the Invention The present invention overcomes the above-mentioned conventional problems, and can easily form higher bumps than conventional ones that can suitably connect bumps on a substrate on which bumps are to be formed by a lift-off method. The object of the present invention is to provide a novel method for forming connection bumps.

(d.) Structure of the Invention According to the present invention, positive resist films and metal layers are alternately deposited in multiple layers on a substrate on which bumps are to be formed, and the uppermost metal layer is coated with a positive resist film and a metal layer. After applying the negative resist, in order to open a predetermined area of the negative resist film,
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and then remove the negative mold with said aperture.
□By providing a method for forming a connection bump, which comprises depositing a conductor layer on a cyst film, and then dissolving and removing each of the resist films to form a high connection bump on the substrate. achieved.

(e) Embodiments of the invention Preferred embodiments of the invention will be described in detail below with reference to the drawings.

FIGS. 4 to 7 are sectional views of main parts showing an embodiment of the method for forming a connection bump according to the present invention in the order of steps. First, as shown in FIG.
A positive resist film 22 is applied, and after drying and hardening, a first metal layer 23 made of, for example, aluminum (Ae) is deposited thereon by vapor deposition or the like. Furthermore, a second positive regime film 24 and a second metal layer 25 made of Al are deposited on the upper surface in the same manner. Next, after coating the surface of the second metal layer 25 with a negative resist film 26, as shown in FIG. Using the negative resist film 26 having the opening 27 as a mask, the second metal layer 25 exposed in the opening 27 is selectively removed by etching, and then the exposed second positive resist film 2 is removed.
4 is selectively exposed to light and dissolved and removed using a developer. Thereafter, in the same manner, after selectively removing the first metal layer 28 and the first positive dinut film 22 exposed in the opening 27 in order to provide a bump placement hole 28, the bump placement hole 28 is formed in the opening 27. As shown in FIG. 6, a soft metal conductor layer 29 made of, for example, indium (In) or the like is thickly deposited on the entire surface of the negative-shaped dinut film 26 including the film 28, as shown in FIG. Next, the first and second metal layers 23, 25 are removed by dissolving, for example, the first and second positive-type cyst films 22, 24 in which the arrangement holes 28 are formed, with the resist stripping solution. (Lift-off step) □': As a result, a bump 80 having a desired height can be easily formed at a predetermined position on the substrate 21 as shown in FIG.

In order to achieve this, we will laminate two layers each of JξFushi-shaped JIS 1-layer IQ and metal I-bud./We will explain an example of this case/However, this is not limited to this, but the required <It goes without saying that it is possible to carry out the method by changing the number of laminated layers of a positive resist film and metal layer depending on the height of the amplifier.

(f) Effects of the invention As is clear from the above explanation, according to the connection bump forming force method according to the present invention, on the substrate on which the bumps are to be arranged,
The lift-off method has the advantage of easily forming bumps that are higher than conventional ones, and the face-down bonding method allows active elements to be bonded to passive circuit boards.
- It is very advantageous to apply it to the formation process of various connection bumps used for mounting on devices.

[Brief explanation of the drawing]

1 to 3 are cross-sectional views of main parts explaining a conventional connection bump forming method step by step, and FIGS. 4 to 7 show an example of the connection bump forming method according to the present invention. )1@
FIG. In the drawings, 21 is a substrate, 22, 24 are first and second metal layers, 26 is a negative resist film, 27 is a 1] part, 28 is a bump arrangement hole, 29B, 1, a metal conductor layer,
80 indicates a connecting bump. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] "A positive resist film and a metal layer are alternately deposited in multiple layers on a substrate on which bumps are to be formed, and a self-metal layer is applied before forming the final layer."
Apply a negative resist to 1. After that, apply a negative resist to 1. - Buttering a predetermined area of the cyst (cyst) to open it 2, using this resist film as a mask, selectively remove the metal layer and the positive resist film exposed in 1 during the above steps, 1 to 2. After that, a conductor layer is deposited on the negative resist film having the opening, and then each of the resist films is dissolved and removed to form a tall connection bump on the substrate. Method for forming bumps for use.