JPS62298138A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To separate easily each unit block, by coating a solder layer on the back surface of a wafer except back surface part in the vicinity of a scribing region, and scribing a wafer to manufacture a pallet. CONSTITUTION:A metal layer 2 providing solderbility is coated and formed on the back surface of a wafer 1 except the back surface part 5 in the vicinity of a scribing region. Recesses 6 are formed by half-dicing of the wafer in the scribe region. The wafer 1 is easily divided along the recesses 6 by breaking the wafer 1. A pellet 7 obtained after the scribing process mentioned above is joined in the ordinary manner to a pellet retaining substrate by soldering. As the result, each unit block is easily separated only by breaking after half- dicing of a wafer.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a technique that is effective when applied to the joining of semiconductor pellets.

[Conventional technology]

One of the so-called guibonding techniques, in which semiconductor pellets (hereinafter also simply referred to as pellets) are attached to a pellet mounting board such as a puff cage board, is performed using solder. Regarding this solder connection method, please refer to January 1, 1980.
It is explained in 1P100 published by Kogyo Kenkyukai Co., Ltd. and published by Japan Microelectronics Association [rlC implementation technology] on the 5th.

By the way, the semiconductor pellet has silicon (Si) in -a.
It is manufactured by dividing a semiconductor wafer (hereinafter simply referred to as a wafer) made of a single crystal or the like into unit blocks. An active region formed by electrically connecting a large number of circuit elements is formed on the surface of the unit block.

When using the above solder connection method, since silicon does not have solder wettability, a metal with good solder wettability is placed on the back surface (opposite the circuit element formation surface) of the semiconductor pellet, which is the bonding surface. It is necessary to form a solderability-imparting metal layer in advance.

The formation of the solderability-imparting metal layer is performed on the entire back surface of the wafer, which is the non-circuit element forming surface, in the wafer state before it is divided into pellets. For example, if the wafer is a silicon single crystal, titanium (Ti), Niacel (Ni), and gold (Au) are sequentially laminated on the silicon crystal surface on the back side of the wafer to form a three-layer solderability-imparting metal layer. can be formed.

[Problem that the invention seeks to solve]

As described above, when forming the solderability imparting metal layer on the entire back surface of the wafer, there are the following problems. That is,
In the case where the wafer is half-diced to form a scribe line, a break is made at the scribe line, and then each bottom left is separated to separate each pellet,
Since the solderability imparting metal layer is difficult to cut, it is difficult to separate the metal layer, and defects such as chips are likely to occur in the pellet at that time.Also, the wafer is fully diced to separate the semiconductor pellets. If this is done, the metal layer is also cut with the dicing blade, which shortens the life of the blade. This is thought to be due to the formation of hard intermetallic compounds associated with the deposited metal layer.

SUMMARY OF THE INVENTION An object of the present invention is to provide a technique by which semiconductor pellets having a solderability-imparting metal layer deposited thereon can be easily separated from a semiconductor wafer.

Another object of the present invention is to provide a technique that can prevent shortening of the life of a dicing blade when fully dicing a semiconductor wafer and dividing the semiconductor pellets.

The above and other objects and novel features of the present invention are:
It will become clear from the description herein and the accompanying drawings.

[Means for solving problems]

A brief overview of typical inventions disclosed in this application is as follows.

That is, a solderability-imparting metal layer is applied to the back surface of a semiconductor wafer except for the back surface near the scribe area, the wafer is scribed to form a semiconductor pellet, and the pellet is attached using solder. It is used to manufacture semiconductor devices by bonding to a substrate.

[Effect]

According to the above-mentioned means, since no solderability-imparting metal layer is attached to the scribe area, which is the boundary between each unit block constituting the semiconductor pellet, each unit block can be separated by simply breaking after half dicing the wafer. can be easily separated.

In addition, since there is no solderability imparting metal layer in the scribe area on the backside of the wafer, even when the wafer is fully diced, the dicing blade does not come into contact with the metal layer, which shortens the life of the blade. can be prevented.

〔Example〕

FIGS. 1a) to 1dl are schematic partial cross-sectional views showing a semiconductor wafer scribing step, which is one step of a method for manufacturing a semiconductor device according to an embodiment of the present invention.

Moreover, FIG. 2 is a schematic partial sectional view showing a scribing process of a semiconductor wafer bonded to a film.

FIG. 1+al shows a step in which a solderability imparting metal layer 2 is deposited on the back surface of a semiconductor wafer 1.

Here, on the surface of the wafer l, an active region 3 is formed in which a large number of circuit elements are electrically connected.
A scribe area 4 is provided at the boundary between adjacent active areas 3.
is provided.

The solderability imparting metal layer 2 is formed on the back surface of the wafer 1 excluding the back surface portion 5 near the scribe area.

Specifically, a resist film (not shown) corresponding to the back surface portion 5 is formed on the back surface of the wafer, and using the resist film as a mask, titanium (Ti), nickel (Ni), and gold (
It is possible to form a three-layer structure by sequentially stacking Au) by suvafuta deposition or the like.

FIG. 1(b) shows the dicing process. That is, after the solderability imparting metal layer 2 is deposited in the above process, the wafer 1 in the scribe area is cut in half with a dicing blade (not shown) as shown in the figure. Dicing is performed to form cuts 6.

FIG. 1 fcl shows the breaking process. By breaking the wafer 1 after forming the cuts 6 by the half dicing, the wafer 1 can be easily divided at the positions of the cuts 6. As a result, the semiconductor pellet 7 shown in FIG. There is.

The semiconductor pellet 7 obtained through the above-mentioned scribing process is halved onto a pellet mounting board using a conventional method.

Manufacturing of a semiconductor device (not shown) is achieved by performing wire bonding, further performing electrical connections such as wire bonding, and passing through other usual processes.

In the die bonding process, in order to automate the process, the back side of the semiconductor wafer 1 is bonded to a film 8 made of polyimide resin, etc., as shown in FIG. 7 automatic transportation etc. At this time, after scribing, the film 8 is heated and stretched in the direction of the arrow, thereby separating the semiconductor pellets 7 at a predetermined gap, as shown in FIG. Thereafter, the separated pellets 7 can be peeled off from the film 8 and at the same time be held between collets to perform gui bonding.

It should be noted that the semiconductor pellet 6 manufactured according to this example has a region of $2 in which the solderability imparting metal layer 2 is not deposited on the peripheral edge of the back surface thereof.

As described above, according to this embodiment, the following effects can be obtained.

(1) By depositing and forming the solderability imparting metal layer 2 on the back surface of the semiconductor wafer excluding the back surface portion near the scribe region, half dicing is performed in the scribe region, and the wafer 1 is broken at the half dicing region. In this case, since there is no metal layer on the back surface portion corresponding to the scribe area, the wafer 1 can be scribed without being affected by the metal layer.

(2) According to (1) above, it is easy to divide the pellet 7;
Since this can be done reliably, it is possible to prevent defects such as chips from occurring in the pellets 7.

(3) According to (2) above, it is possible to improve the yield of semiconductor pellets with guaranteed solderability.

(4) According to (2) above, when scribing the wafer 1 with the back surface of the wafer 1 bonded to the polyimide film 8 and then separating the semiconductor pellets by heating and stretching the film 8, the separation is easy; Since it can be performed reliably, semiconductor pellets suitable for die bonding automation can be reliably provided.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, although only the three layers of titanium, nickel, and gold have been described as the solderability-imparting metal layer 2, the present invention is not limited to this. It may be formed of any metal material that can be used, and may have any number of layered structures.

Furthermore, in the embodiment described above, an example has been described in which the scribing of the wafer 1 is performed by half dicing and subsequent breaking, but the present invention is not limited to this.

For example, the wafer 1 may be fully diced. When performing full dicing in this way, by applying the wafer shown in the above embodiment, dicing of the solderability imparting metal layer 2 can be avoided. Because it is possible to
Another advantage is that the life of the dicing blade can be prevented from being shortened.

In the above explanation, the invention made by the present inventor was mainly applied to semiconductor wafers made of silicon, which is its field of application, but it is not limited thereto. This is an effective technique that can be applied to various semiconductor wafers made of semiconductors and the like.

〔Effect of the invention〕

A brief explanation of the effects obtained by typical inventions disclosed in this application is as follows.

That is, each unit constituting the semiconductor pellet is manufactured by depositing a solderability-imparting metal layer on the back surface of the semiconductor wafer, excluding the back surface near the scribe area, and scribing the wafer. Since it is possible to create a structure in which no solderability-imparting metal layer exists in the scribe area that is the boundary between blocks, it is possible to easily separate each unit block when breaking the wafer after half dicing. . As a result, it is possible to reliably provide a semiconductor pellet that can be used for automation of guiponding.

In addition, since there is no solderability imparting metal layer in the scribe area on the back surface of the wafer, even when the wafer is fully diced, the metal layer is not diced.
This can prevent the life of the dicing blade from being shortened.

[Brief explanation of drawings]

FIGS. 1(a) to (dl) are schematic partial cross-sectional views showing a semiconductor wafer scribing step, which is one step of a semiconductor device manufacturing method according to an embodiment of the present invention; FIG. 2 is a semiconductor bonded to a film; FIG. It is a schematic partial sectional view showing a wafer scribing process. 1... Semiconductor wafer, 2... Solderability imparting metal layer,
3...Active area, 4...Scripe area, 5
. . . back surface portion, 6 . . . notch, 7 . . . semiconductor pellet, 8 . . . film.

Claims (1)

[Claims] 1. Applying a solderability-imparting metal layer to the back surface of a semiconductor wafer except for the back surface near the scribe area, scribing the semiconductor wafer to form a semiconductor pellet, and forming a semiconductor pellet by scribing the semiconductor wafer. A method of manufacturing semiconductor devices in which attachment is performed using solder. 2. The semiconductor wafer is made of silicon single crystal, and the solderability-imparting metal layer is formed by sequentially laminating titanium, nickel, and gold on the back surface of the wafer. A method for manufacturing a semiconductor device.