JPH02159033A - Semiconductor device - Google Patents

Abstract

PURPOSE:To improve the strength of close contact between a lead and a bump by causing a contact window to be formed into the shape of a rectangle where its longitudinal side is at a right angle to a lead connecting to a bump electrode and making its location to deflect to the pointed end side of the lead rather than the center position of the bump electrode. CONSTITUTION:An insulating layer 4 is formed on a semiconductor substrate 3 and a metallic wiring layer including a pad 5 is formed on the above layer 4. Then an insulating layer 6 covering the whole body is formed after making up a three-layer structure consisting of PSG, SiN, and polyimide and then a contact window 2 is formed at the pointed end side of the lead 9 rather than the center of the bump and is formed into the shape of a rectangle as well. Subsequently, Ti and Pd are formed extensively as a barriermetal layer 7. A part corresponding to the bump 1 is removed by applying a resist layer 11 on the barrier/metal layer 7. The bump 1 plated with gold is laminated on the barrier/metal layer 7 which is not covered with resist 11 by using the barrier/metal layer 7 as an electrode through electrolytic plating. After removing the resist 11, Ti and Pb of the barrier/metal layer 7 are removed by etching.

Description

[Detailed Description of the Invention] [Summary] With regard to semiconductor devices suitable for the TAB process in semiconductor device manufacturing, especially the plating bumps of semiconductor devices, even if the size of the plating bumps is reduced, the gap between the leads and bumps and between the bumps and the substrate will be reduced. In order to provide a plating bump that can simultaneously ensure adhesion, a contact window is provided in an insulating layer that covers a pad on a semiconductor substrate to expose the pad, and the pad is exposed to the bump through the contact window. In a semiconductor device provided with an electrode, the contact window has a rectangular shape whose longitudinal direction is perpendicular to the lead connected to the bump electrode, and/or the contact window is located closer to the tip of the lead than the center of the bump electrode. It is configured so that it deviates to the side.

[Industrial Field of Application] The present invention is applicable to TAB (tape au
t.

The present invention relates to a semiconductor device suitable for a mated bonding process, and in particular to a plating bump for a semiconductor device.

As a multi-pin connection technology for semiconductor devices, TAB has become widely adopted as a more preferable means for solving the problems faced by wire bonding.

[Prior art] In the TAB process, improving the adhesion (connection strength) between the lead and the bump and the adhesion between the bump and the semiconductor substrate (i.e., the pad, which is the wiring on the semiconductor substrate) improves the yield. Required for improvements and improved reliability.

When forming bumps with plating such as gold (Au),
As shown in FIGS. 2 and 7B, the profile of the surface to which plating is applied is a plating bump surface profile. In order to increase the adhesion between the lead and the bump, it is possible to increase the contact area between them, but since the overall size of the bump is regulated, the contact area provided on the insulating layer, which is the contact area between the bump and the substrate, is The window will have to be made smaller. However, if the contact window is made smaller, the adhesion between the bump and the substrate will be reduced, and there is a risk that the bump will peel off. Therefore, it is necessary to form the contact window so as to ensure both the adhesion between the lead and the bump and the adhesion between the bump and the substrate.

The plating bump 1 of the conventional semiconductor device is square, as shown in FIGS. 7A and 7B, and the contact window 2
It is also square and located at the center of the bump 1. In this case, there is an insulating layer 4 on the surface of the semiconductor substrate 3, on which metal wiring including pads 5 is formed, and an insulating layer 6, which is also a badge film of the semiconductor substrate, covers the whole, and the pads 5 A contact window 2 is formed on top.

Usually, the pad 5 is made of an aluminum alloy, and a barrier metal layer 7, which also serves as an electrode during electrolytic plating, is bonded to the pad 5 within the contact window 2 and formed on the insulating layer 6, as shown in FIG. 1B. ing. A on this barrier metal layer 7
Plating bumps 1 such as U are laminated by electrolytic plating, and a recess 8 corresponding to the contact window 2 is formed in the center thereof. Then, on the Metsuki bump 1, Au, tin (
Leads 9 such as Sn) are attached to areas A and B by thermocompression bonding.
It is glued at.

[Problems to be Solved by the Invention] As the size of individual bumps becomes smaller due to the increase in the number of pins in semiconductor devices, the contact area between lead 9 and bump 1 (area of regions A and B) increases. As a result, the adhesion strength between the lead and the bump decreases. In order to ensure this adhesion strength, if the contact window 2 is made smaller, the adhesion strength between the bump and the pad is proportional to the area of the contact window, so the adhesion strength here will decrease. Furthermore, the contact resistance of the pad increases. Therefore, since the size of the contact window 2 cannot be easily reduced, if the bump size is reduced, there is a problem in ensuring both the adhesion between the lead and the bump and between the bump and the substrate.

An object of the present invention is to provide a plating bump that can simultaneously ensure adhesion between the lead and the bump and between the bump and the substrate even if the size of the plating bump is reduced.

[Means to solve the problem]

The above purpose is insulation covering the pads on the semiconductor substrate!
- a layer is provided with a contact window exposing said pad;
In a semiconductor device in which a bump electrode is provided on the pad through the contact window, the contact window is rectangular with a longitudinal direction perpendicular to the lead connected to the bump electrode; and/or This is achieved by a semiconductor device characterized in that the bump electrode is deviated from the center position toward the tip of the lead.

[For production]

According to the present invention, the lead-bump contact area (corresponding to area A in FIG. 1A) where the lead peels first occurs without changing the surface speed of the contact window (that is, the adhesion between the bump and the substrate). This is based on the fact that adhesion between the lead and the bump can be ensured by increasing the area of the bump.

In this way, first, as shown in FIG. 6, the shape of the contact window can be changed from the conventional square to a rectangle in the direction perpendicular to the lead without changing the position of the contact window, thereby improving the lead bump. The area of the contact area increases. Second
As shown in Fig. 5, if the contact window position is shifted from the center of the plating bump toward the lead tip side, the area of the lead-bump contact area on the lead tip side decreases, and the lead on the outer periphery of the semiconductor device decreases accordingly. - The area of the bump contact area increases. The third case, which is a combination of the first and second combinations described above, is preferable because the area of the lead/bump contact region on the outer peripheral side of the semiconductor device can be further increased.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 is a partial plan view of bumps and leads of a semiconductor device according to the present invention, and FIG. 2 is a cross-sectional view thereof. The bumps of the semiconductor device of the present invention have a similar structure to the bumps of conventional semiconductor devices, and the same parts are designated by the same reference numerals. In particular, in this case, the position of the contact window 2 is shifted toward the lead tip side, and the contact window shape is rectangular.

The plating bump l of the semiconductor device is made, for example, as follows.

First, as shown in Figure 3, according to the normal process,
An insulating layer 4 is formed on a semiconductor substrate 3 made of silicon or the like, and a metal wiring (Af-Si alloy with a thickness of 1.OI!m) including a pad 5 is formed thereon. Next, an insulating layer 6 covering the entire structure is formed with a three-layer structure of PSG (1, On thickness), 1.5 iN (0.3 inch thickness), and polyimide (2.0 inch thickness).

As shown in FIG. 4, a contact window 2 is formed in the insulating layer 6 by a normal phosphorography method. The position and shape of this contact window 2 are as shown in FIG.
Compared to the diagram, in relation to the mating bump 1, the bump center is moved to the left in the diagram (toward the lead tip side) and rectangular. Assuming that the area of the contact window 2 is the same as in the conventional case,
The adhesion strength between the bump and the substrate is maintained the same. Next, Ti (500 nm thick) and Pd (300 na+thick) are formed as a barrier metal layer 7 over the entire surface of the contact window 2 including the portion that contacts the pad 5 by sputtering. A resist layer (
A thickness of 304) 11 is applied, and the portion corresponding to bump 1 is removed by exposure and development. Then, the resist 11 is electrolytically plated using the barrier metal layer 7 as an electrode.
A gold plating bump 1 (thickness: 25III) is laminated on the barrier metal layer 7 which is not covered. The position and shape of this bump 1 are conventional (Fig. 7A, 7B).
The recess 8 created on the top surface of the bump bump 1 is the same as in the figure).
The position and shape of the contact window 2 change depending on the contact window 2.

After removing the resist 11, using the plating bump 1 as a mask, Ti and PB of the barrier metal layer 7 are removed by etching with hydrogen peroxide ammonia and aqua regia. After chip processing, inner lead bonding (
ILB) process, heat compression bonding (400-500°C)
(for several seconds) (Figures 1 and 2).

In the mated bump 1 with the leads 9 attached in this way, the total area of the contact areas al and bl is larger than the total area of the conventional contact areas A and B (FIG. 7A), and furthermore, peeling begins to occur. The contact area al
The area of the contact area A is larger than that of the conventional contact area A. therefore,
In the case of the present invention, the adhesion strength between the lead and the bump is greater than that of the prior art.

A semiconductor bump according to another embodiment of the present invention is shown in FIG. In this case, the square contact window 2 has the same shape as the conventional one (FIG. 7A), but its position is shifted toward the lead tip side from the center of the bump. Therefore, the total area of the contact areas a2 and b2 between the lead 9 and the plating bump l formed as described above is the same as in the conventional case (FIG. 7A), but the contact area b2 is larger than the conventional one by the amount of positional shift. The contact area a2 is also smaller than the conventional contact area A. Therefore, in this case as well, the adhesion strength between the lead and the bump is greater than in the conventional case.

Further, a semiconductor bump according to another embodiment of the present invention is shown in FIG. In this case, the contact window 2 has a different shape from the conventional one (FIG. 7A), and its shape is a rectangle with an elongated direction perpendicular to the leads. Even in this case, the area of the contact window 2 is the same as before, and the lead/bump contact area a is elongated.
The total area of 3 and b3 is larger than the conventional one, and the contact area a3 is also larger than the contact area A.

Therefore, the adhesion strength between the leads and bumps is greater than that of the prior art.

[Effects of the Invention] As explained above, according to the present invention, the contact area between the bump and the substrate can be maintained as is by changing the position and shape of the contact window between the semiconductor plating bump and the substrate from the conventional one. (at a constant value), it is possible to increase the contact area between the lead pan 1 (particularly between the lead and bumps where peeling tends to occur on the outer peripheral side of the semiconductor device). As a result, the adhesion strength of the lead pan can be improved, yield and reliability can be improved, and the present invention can be applied to miniaturization of Menki bumps in the future.

[Brief explanation of the drawing]

FIG. 1 is a partial plan view of a semiconductor plating bump and bonded leads according to the present invention, FIG. 2 is a partial cross-sectional view corresponding to FIG. 1, and FIGS. FIGS. 5 and 6 are partial cross-sectional views at an intermediate step in manufacturing the semiconductor plating bump (FIGS. 1 and 2) according to the present invention; FIGS. 5 and 6 are schematic diagrams of the semiconductor plating bump and leads of another embodiment of the present invention 7A is a partial plan view of a plating bump and lead of a conventional semiconductor device; FIG. 7B is a partial sectional view corresponding to FIG. 7A; FIG. l...Metsuki bump, 2...contact window,
5... Pad, 6... Insulating layer, 9...
・Lead. Plan view of the semiconductor device bump of the present invention FIG. 1 New view of FIG. 1 FIG. 20 FIG. knee diagram FIG. 6

Claims (1)

[Claims] 1. A semiconductor device in which an insulating layer covering a pad on a semiconductor substrate is provided with a contact window that exposes the pad, and a bump electrode is provided on the pad through the contact window, A semiconductor device, wherein the contact window has a rectangular shape whose longitudinal direction is perpendicular to a lead connected to the bump electrode. 2. A semiconductor device in which an insulating layer covering a pad on a semiconductor substrate is provided with a contact window that exposes the pad, and a bump electrode is provided on the pad via the contact window, wherein the contact window is A semiconductor device characterized in that the bump electrode is deviated from the center position toward the tip of a lead connected to the bump electrode. 3. In a semiconductor device in which a contact window exposing the pad is provided in an insulating layer covering a pad on a semiconductor substrate, and a bump electrode is provided to the pad via the contact window, the contact window has a longitudinal direction. A semiconductor device characterized in that the semiconductor device has a rectangular shape whose direction is perpendicular to a lead connected to the bump electrode, and the semiconductor device is deviated from the center position of the bump electrode toward the tip of the lead.