JPS6020521A - Semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a wiring, dimensional accuracy thereof is high and resistance thereof is low, by forming the wiring on a package substrate by a multilayer wiring consisting of chromium and copper. CONSTITUTION:A wiring 4 is formed as three layer thin-film multilayer wirings consisting of a chromium layer 10 formed on a package substrate 1 after sintering through the evaporation of a thin-film, a copper layer 11 evaporated on the layer 10 in a thin-film shape and a chromium layer 12 evaporated on the layer 11 in the thin-film shape. A pedestal section 5 is composed of a copper layer 13 evaporated on the chromium layer 12 as the uppermost layer of the wiring 4 in the thin-film shape and a chromium layer 14 evaporated around the copper layer 13 in the thin-film shape. Since the wiring 4 is formed by the three layer thin- film evaporated layers of the chromium layer 10, the copper layer 11 and the chromium layer 12, the wiring 4 and the pedestal section 5 are formed with dimensional accuracy higher than a tungsten wiring formed through sintering. Accordingly, a large-sized pellet can be face-down bonded, and the resistance of the wiring 4 can be lowered by the presence of the copper layer 11.

Description

[Detailed Description of the Invention] [Technical Field] The present invention is effective when applied to a semiconductor device, particularly a semiconductor device of the type in which a peresode 1- is bonded to the wiring of a package substrate by face-down bonding using a flip-chip method. It's about technology.

[Background Art] In a semiconductor device in which a pellet is connected to wiring on a package substrate by face-down bonding using a flip-chip method, the wiring on the ceramic package substrate is made of paste-like tungsten (W) patterned on the substrate.
') may be formed by simultaneously sintering the ceramic package during firing.

However, in this case, since the package shrinks during sintering, the package size is variable, so the control unit 1-1-1-1 is a recirculating lamp. In particular, in the face-down bonding method in which a hump electrode for bonding is provided on the surface of the Peresol l-, the dimensions of the tungsten wiring may be distorted due to shrinkage of the package, and the reliability of the bump connection after bonding may be insufficient. The inventor of the present invention has discovered that there is a problem in that it cannot be used.

[Object of the Invention] An object of the present invention is to provide a semiconductor device including wiring with high dimensional accuracy and low resistance.

Another object of the present invention is to provide a semiconductor device having a pedestal portion for bullet bonding that has good solder wettability and is less likely to be eaten away by solder.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Summary of the Invention] A brief overview of typical inventions disclosed in this application is as follows.

In other words, chromium (Cr) is used as wiring on the package substrate.
) and copper (Cu) by vapor deposition after firing the ceramic package, it is possible to obtain wiring with high dimensional accuracy and low resistance.

Further, by forming the pedestal portion for joining the wiring and the bullet with a combination of chromium and copper or an alloy thereof, it is possible to obtain a pedestal portion with good solder wettability and less solder erosion.

Furthermore, since a titanium layer is also formed between the copper and the package substrate, the adhesion between the copper and the ceramic package is improved.

[Embodiment 1] FIG. 1 is a sectional view showing an embodiment of a semiconductor device according to the present invention, and FIG. 2 is an enlarged partial sectional view of a wiring portion and a pedestal portion thereof.

In this embodiment, the package substrate 1 is made of ceramic, for example, and has internal wiring 2 formed therein. The lower end of this internal wiring 2 is connected to an axial lead pin 3 which is placed on the back surface of the package substrate 1. On the other hand, the upper end of the internal wiring 2 is connected to a wiring 4 formed on the surface of the puff cage substrate 1.

A pedestal portion 5 for joining pellets is provided protruding from a predetermined portion of the wiring 4. A pellet 7 is joined to the pedestal portion 5 by a face-down bonding method using solder bumps 6, and is electrically connected.

Further, the pellet 7 and the like are hermetically sealed with a cap 9 made of ceramic or the like fixed to the package substrate 1 with a sealant such as low melting point glass 8.

In this embodiment, the wiring 4 is as shown in FIG.
A chromium layer 10 formed by thin film deposition on the package substrate 1 after sintering, copper IN1.1 deposited in a thin film on this chromium N10, and a chromium layer deposited in a thin film on this copper layer 11. It is formed as a three-layer thin film multilayer wiring consisting of 12.

Furthermore, the pedestal portion 5 is made up of a copper layer 13 formed by depositing a YI film on the chromium layer 12 which is the second most layer of the wiring 4, and a chromium layer 14 formed by thin film deposition around the copper layer 13. Become.

In this embodiment, the wiring 4 includes a chromium layer 10 and a copper layer 11.
, 3WI of the chromium layer 12, the wiring 4 and the pedestal portion 5 are formed with better dimensional accuracy than the tanksten wiring formed by sintering. Therefore, face down pounding of large pellets is possible. In addition, the resistance of the wiring 4 can be lowered due to the presence of the copper layer 11, and since the lowest layer is the chromium layer 10, when the copper is directly bonded to the substrate 1, it is possible to form a close bond with the substrate 1. becomes better than non-electricity.

Further, in this embodiment, since the pedestal portion 5 has a structure in which the chromium layer 14 is deposited as a thin film on the copper layer 13, when the bullet 7 is bonded with the solder bump 6, the chromium layer 14 is attached to the copper layer 13.
It is possible to prevent copper from being eaten away by solder (copper being absorbed and combined with solder) and to improve solder wettability.

Furthermore, since the wiring 4 is covered with the titanium layer 12, the copper layer 11 will not be absorbed and combined with excess solder.

Embodiment 21 FIG. 3 is an enlarged partial cross-sectional view of a main part of a semiconductor device according to Embodiment 2 of the present invention.

In this second embodiment, the wiring 4 on the pan cage board 2
As in Example 1, the chromium layer 10. It consists of a thin film vapor deposited layer of copper scraps 1 and 1203 layers of chromium scraps, and the pedestal part 5 for bump bonding on top of these is a chromium-copper alloy [15,
It has a structure in which a thin film of copper FF16 is deposited thereon. This chromium-copper alloy layer 15 can be formed by depositing chromium and copper together from the beginning, or by depositing chromium and copper separately and then annealing them to form an alloy.

According to the second embodiment, the copper layer 16 is easily wetted by solder.Secondly, the chromium-copper alloy layer 15 serves to prevent solder from being eaten away, making it possible to perform solder bump bonding with high reliability and good dimensional accuracy. It is.

[Embodiment 3] FIG. 4 shows another embodiment of the semiconductor device according to the present invention.

In this embodiment, a plurality of perenos) 7 are mounted on the bag cage board 1.
Although this is a multi-chip type semiconductor device in which parts a and 7b are bonded together by face-down bonding, the present invention is extremely useful even in such a structure.

[Effect] (), The wiring on the package substrate that connects the pellets by face-down bonding consists of a chromium layer on the puff cage substrate, copper scraps on the chromium layer, and a chromium layer on the copper layer. By using thin film multilayer wiring, high dimensional accuracy can be obtained.

(2) Due to the thin film multilayer wiring of fl) above, especially the interposition of the titanium layer, the adhesive bonding between the wiring and the package substrate becomes extremely good.

(3) Low-resistance wiring can be obtained by using the thin film multilayer wiring described in (1) above, especially the copper layer.

(Secondly, by forming the pedestal portion for joining the wiring and the pellet with a multilayer of a chromium layer and #pI scraps or an alloy layer of chromium and copper, wettability to solder can be improved.

(5) The pedestal portion described in (4) above can prevent erosion by solder.

(6), 14), and +5) allow highly reliable face-down bonding.

Although the invention made by the present inventor has been specifically explained based on Examples above, the present invention is not limited to the above Examples, and it is possible to make various changes without departing from the gist of the invention. Not even.

For example, the pedestal part can be formed as a multilayer thin film structure of three or more layers with a chromium layer interposed below the copper layer or chromium-copper alloy layer below the pedestal part.

In addition, the thin film on the wiring or pedestal portion may be formed by a method other than vapor deposition.

[Brief explanation of the drawing]

FIG. 2 is an enlarged partial sectional view of one embodiment of the wiring and pedestal portion of the semiconductor device according to the present invention; FIG. FIG. 4 is an enlarged partial sectional view showing another embodiment of the semiconductor device according to the present invention. 1...Package board, 2...Internal wiring, 3...
Lead pin, 4... Wiring, 5... Pedestal part, 6
...Solder hump, 7.7a, 7b...Heresoto, 8
...Sealant, 9...Cap, 10...Chromium layer, 11...Copper scrap, 12...Chromium layer, 13...Copper layer, 14...Chromium layer, 15. ...Chromium-copper alloy layer, 16...Copper layer. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. In a semiconductor device in which a pellet is bonded to wiring on a package substrate by face-down bonding, the wiring connects a chromium layer on the package substrate, a copper layer on the chromium layer, and a copper layer on the copper layer. A semiconductor device characterized in that it is a thin film multilayer interconnection consisting of a chromium layer. 2. In a semiconductor device in which a pellet is bonded to wiring on a package substrate by face-down bonding, the pedestal portion for bonding the wiring and vereso 1 to is a multilayer thin film of a chromium layer and a copper layer or an alloy layer thin film of chromium and copper. A semiconductor device characterized by the following. 3. The wiring is in contact with the chromium layer on the package substrate vJ
3. The semiconductor device according to claim 2, wherein the semiconductor device is a thin film multilayer interconnection consisting of a copper layer on the X layer and a chromium layer on the copper layer.