JP2001068514A - Dummy chip with bump and method of evaluating flip-chip packaging - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To evaluate a flip chip mounting process by a simple method and in a short time. SOLUTION: When evaluating a process of flip-chip mounting an LSI chip with bumps on a wiring board, bumps 4 which are the same as the bumps of the product are formed on one side of a dummy chip 1 which is made of transparent glass and has the same dimensions and shape as the LSI chip of the product. A flip chip mounting trial is performed using a dummy chip with bumps formed in the same arrangement as the LSI chip with bumps of the product via the same bump base metal film 2, and the bonding portion of the trial product and its surroundings are dummy chips. By visually observing through 1, bonding position accuracy, bump connection shape, and the like are checked.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a bumped LSI.
The present invention relates to a dummy chip with bumps for evaluating a step of flip-chip mounting a chip on a wiring board, and a flip-chip mounting evaluation method using the same.

[0002]

2. Description of the Related Art When starting a step of mounting an LSI chip with bumps on a wiring board by flip chip bonding (including cleaning and underfill in addition to flip chip bonding), or an LSI with bumps to be flip chip mounted
When the I-chip is switched to another type having different chip size, number of bumps, bump arrangement, bump material, bump dimensions, etc., a dummy chip with bumps is flip-chip mounted on a wiring board (ie, a trial is performed). It is necessary to evaluate the process by checking the quality of the trial product, and to fine-tune the processing apparatus and optimize the processing conditions according to the result. Typical quality check items are bonding position accuracy, bump connection shape, incomplete filling of underfill resin, incomplete flux cleaning, and the like.

Conventionally, in a trial for evaluating the flip-chip mounting process, an LSI chip with bumps of a product to be flip-chip mounted is used as a dummy chip with bumps. Ultrasonic flaw detection, cross section polishing, etc. were used.

[0004]

However, X-ray fluoroscopy, ultrasonic inspection, cross-section polishing, and the like are not simple tasks, and the conventional technique requires a long time to evaluate the flip-chip mounting process. there were.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for evaluating the mounting of a dummy chip with bumps and a flip chip, which can solve such a problem and can check the quality of a trial product in a simple manner and in a short time.

[0006]

In order to achieve this object, the present invention provides a method for evaluating a process of flip-chip mounting a bumped LSI chip having bumps on one surface of an LSI chip on a wiring board. A dummy chip made of transparent glass and having the same dimensions and shape as the LSI chip is provided on one surface of the dummy chip with the same bumps as the bumps of the LSI chip with bumps. A dummy chip with bumps, which is arranged and arranged via the same bump base metal film as the LSI chip with bumps.

In the present invention, a flip chip mounting evaluation method is characterized in that after bonding the dummy chip with bumps on a wiring board by flip chip bonding, the bonding quality is checked through the dummy chip. I have.

In the present invention, the dummy chip with bumps is flip-chip bonded to a wiring board, and a resin is filled in a gap between the dummy chip and the wiring board. The flip chip mounting evaluation method is characterized by checking through a chip.

That is, in the present invention, since the dummy chip is made of transparent glass, it is troublesome to perform X-ray fluoroscopy, ultrasonic inspection,
The bonding position accuracy, the connection shape of the bumps, the filling state of the underfill resin, and the like can be visually observed through a dummy chip in a non-destructive manner without performing cross section polishing or the like. On the other hand, glass has a coefficient of thermal expansion close to that of Si constituting an LSI chip, and it is possible to form the same underlying metal film as the LSI chip. Therefore, if the chip dimensions, bumps, base metal, etc. are matched to the product to be flip-chip mounted, evaluation of the flip-chip mounting process can be performed easily and in a short time based on the results of trial using dummy chips made of transparent glass. it can.

[0010]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described with reference to FIG. FIG. 1 is a schematic sectional view showing an embodiment of the present invention. In the figure, 1 is a dummy chip, 2 is a UBM (metal substrate under bump), 3 is a bump, 4
Is a surface protective film.

The material of the dummy chip 1 is transparent glass, and its dimensions and shapes are the same as those of the product to be flip-chip mounted.
Same as the SI chip. The UBM 2 is formed on one side of the plate-shaped dummy chip 1 in the same arrangement as the product LSI chip, and its material (for example, Ti / Ni) and dimensions are the same as those of the product LSI chip. The bump 3 is the same as the bump of the bumped LSI chip of the product (the material is solder, Au, Sn-Ag, etc.).
The same number and the same arrangement as the SI chips are formed on one surface of the dummy chip 1 via the UBM 2. Further, the LS of the product is placed on the exposed portion of the dummy chip 1 where the bump 3 is formed.
The same surface protection film 4 as the I chip is applied (for example, a nitride film, a polyimide film).

The dummy chip with bumps can be manufactured as follows. First, a metal film (for example, Ti / Ni) serving as a UBM is formed on one surface of a wafer-shaped glass plate.
Is deposited by a sputtering method. Next, a resist film is formed on the metal film, and the resist film is patterned. Next, this metal film is used as a plating conductive film by soldering using a plating method, A
A bump such as u, Sn-Ag is formed. Next, the metal film is etched using the bumps as a mask, and thereafter, the glass wafer with the bumps is diced into dummy chips with bumps.

If it is necessary to apply a surface protective film or reflow bumps, the process is performed before the dicing step. Also,
As the bump forming method, there are a printing method, a transfer method, a metal jet method, a stud bump method and the like in addition to the plating method described above.

Next, a method for evaluating the flip-chip mounting process of the present invention will be described. First, after the dummy chip with bumps is flip-chip bonded to a wiring board, bonding quality such as bonding position accuracy and bump connection shape is checked by visual observation of a bonding portion through the dummy chip. The flip chip bonding process is evaluated based on the result.

After the flip chip bonding, cleaning is performed. Thereafter, the bonding portion and its surroundings are visually observed through the dummy chip to check the cleaning quality such as the presence of residual flux. Evaluate the washing process.

The gap between the dummy chip and the wiring board after the flip chip bonding is filled with resin, and the resin filling portion is visually observed through the dummy chip to check for filling defects such as voids. The underfill process is evaluated based on the result. Incidentally, the behavior of the resin at the time of filling the resin can be observed through a dummy chip. Therefore,
By observing the behavior of the resin, it is possible to more accurately evaluate the underfill step, and also to evaluate the resin itself and the design of the mounting member.

The present invention is not limited to the above examples,
Further, various modifications can be made.

[0018]

As described above, according to the present invention,
It is possible to provide a dummy chip with bumps and a flip chip mounting evaluation method that can evaluate the flip chip mounting process in a simple manner and in a short time.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dummy chip 2 UBM (under bump metal film) 3 Bump 4 Surface protective film

Claims (3)

[Claims] 1. A dummy chip with bumps for evaluating a step of flip-chip mounting an LSI chip with bumps on one surface of an LSI chip on a wiring board, the dummy chip being made of transparent glass and having a dimensional shape. Is provided on one surface of a dummy chip which is the same as the LSI chip, a bump base metal film having the same arrangement as the bumps of the bumped LSI chip and having the same arrangement as the bumped LSI chip, and the same as the bumped LSI chip. A dummy chip with bumps, wherein the dummy chip has bumps. 2. A flip-chip mounting evaluation method, comprising: after flip-chip bonding the dummy chip with bumps according to claim 1 to a wiring board, checking bonding quality through the dummy chip. 3. The method according to claim 1, wherein the dummy chip with bumps is flip-chip bonded to a wiring board, and a resin is filled in a gap between the dummy chip and the wiring board. A flip-chip mounting evaluation method characterized by checking through.