JPH0429343A - Semiconductor device method of forming mark for identifying - Google Patents

Abstract

PURPOSE:To shorten the working hours without being affected by the number of chips by applying light to the film, which covers the top face being selected from among the group consisting of circuit components such as an active element, a receiving element, a resistor built in a semiconductor substrate, so as to discolor it to judge whether the properties are good or bad. CONSTITUTION:A polyimide film 7 is applied uniformly on a semiconductor substrate 2. An incandescent lamp, which discolors the polyimide film 7, is arranged in an optical system 8 and light is applied to the spot (Spot) smaller than the semiconductor chip 4, whose alignment is finished, so as to discolor the polyimide film 7 to form a mark 6 for identifying a semiconductor element, and by repeating this method, a plurality of discolored marks 6 for identifying semiconductor devices are formed. Accordingly, besides being capable of forming the sizes constant, the variation in dimensions by positions can be suppressed. Thus, working hours can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for forming a semiconductor element identification mark indicating the result of a die sorter test on a semiconductor chip.

(Prior art) Scribe line formed on a semiconductor wafer (hereinafter referred to as substrate)
A predetermined impurity is introduced and diffused into the areas divided by the above, and one or more types selected from the group consisting of circuit components such as active elements, passive elements, or resistors are provided.
Divide by mechanical means along the scribe line (Br
aking) to form a semiconductor chip (Chlp). The general method for determining the characteristics of these semiconductor chips is to use a so-called die sorter test to classify them into good and defective products before proceeding to a subsequent process. After this sorting, each chip is given a diameter of 11 to 3 by Innker.
Ink (I
nk) so that the results can be confirmed visually. FIG. 1 shows a plurality of chips in which a semiconductor element identification mark is formed approximately in the center. This first
As shown in the figure, the orientation
A mesh-like scribe line 3 is formed on a semiconductor substrate 2 made of silicon, for example, on which a flat portion 1 is formed, and semiconductor element identification marks 5 are formed near the center of chips 4 divided by this.・is formed.

The semiconductor chip 4 with the semiconductor element identification mark 5... is mounted on a lead frame (L) by a robot mechanism attached to a mounter (Mountcr).
It goes without saying that the semiconductor chip is mounted on an ead frame, and is also divided into chips by the dividing process as described above.

In the mounting process, ITV (Industrial
Semiconductor chip 4 shown on Te1evislon)
An attached device such as a microcomputer determines whether or not the semiconductor element discrimination mark 5 is a good product or not, and the robot mechanism operates based on the result. By the way, the results of the die sorter test for determining good products and defective products are stored on a floppy disk (Floppy disk).
In addition to being sent to the inker via an online system (On Line 5yste11) such as a transmission line (Disk) or a transmission line, data such as which semiconductor chip to attach the semiconductor element identification mark 5 to is also created and sent to the inker in the same way. It will be sent and saved to. Note that the semiconductor chip 4 supplied to the mounter is illuminated by an incandescent light bulb.

(Problem to be Solved by the Invention) The process of applying ink to the semiconductor chip prior to the mounting process uses one type of ink, such as red or black, and is also limited to one type of shape. Naturally, only good/bad judgment could be made. However, elements built into semiconductor chips, such as IC (Integrated
C3rcu4t) and LSI (Large 5cale
Integrated C1rcu4t) requires rank classification according to characteristics, but this cannot be met. Furthermore, in order to process a large number of semiconductor chips, different types of input forces must be used, so semiconductor chips with identification marks for semiconductor elements of different diameters are also disposed of. Along with this, the operating mechanism of the mounter had to be changed, and the index (
index).

In addition, dust and the like may adhere to the comparatively small-diameter identification marks for semiconductor devices illuminated by the lighting equipment, and furthermore, depending on the illuminated position, the mounter may make false detections or may be unable to detect them.

Moreover, since the ink requires time to dry, there are problems such as a long construction period. The present invention was made under these circumstances, and particularly aims to shorten the working time without being affected by the number of chips.

[Configuration of the Invention (Means for Solving the Problem) A film covering the top surface of one or more types selected from the group consisting of circuit components such as active elements, passive elements, or resistors built into a semiconductor substrate is exposed to light. The method for forming a discrimination mark for a semiconductor device according to the present invention is characterized in that it is possible to determine whether the characteristics are good or bad by applying a wafer and changing color.

(Function) Polyamide resin, for example, is suitable as a film that changes color when exposed to light for the identification mark for semiconductor devices, and a white light bulb made from a tungsten filament is used as the light source essential for forming this mark. Make use of it. In addition, in order to form a film that changes color when exposed to light in multiple locations, a mask made of a material that transmits light and a material that does not transmit light is used, and the number of types that change color due to light is increased to allow identification of multiple types of semiconductor devices. To form the marks, we adopted a method of adding pigment to polyimide resin.

(Example) An example according to the present invention will be described with reference to FIGS. 2 to 7, and parts that are the same as those shown in the prior art column will be described with the same numbers. First, FIG. 2 shows a semiconductor substrate 2 on which a semiconductor element discriminating macro is formed by the method of the present invention. This semiconductor substrate 2 has an orientation flat part 1 formed thereon as before, and is partitioned by providing scribe lines 3 vertically and horizontally, and a predetermined impurity layer is introduced and diffused inside to form circuit components such as active elements, passive elements, or resistors. The method of the present invention is applied to a plurality of chips 4 formed with one or more types selected from the group consisting of: As shown in FIG. 3, such a semiconductor substrate 2 is coated with a photoresist film, for example, a polyimide film 7, which changes color when exposed to light, uniformly to a thickness of 25 μm to 50 μm using a centrifugal separation method, and the semiconductor chip 4 is also coated with it. The entire surface is covered.

The optical system 8 shown in the figure is equipped with an incandescent light bulb (not shown) that discolors the polyimide film 7, and illuminates a spot smaller than the aligned semiconductor chip 4 to discolor the polyimide film 7. By repeating this process, a plurality of discolored discrimination marks 6 for semiconductor elements can be formed. Moreover, not only can the size be made constant, but also variations in dimensions depending on position can be suppressed.

Since the semiconductor element discrimination mark 6 in the above embodiment has one type of color and shape, it is only possible to determine whether the semiconductor element is good or bad. In order to meet this requirement, the present invention utilizes a film that can change color differently depending on the wavelength of light. That is, a pigment that changes color is added to the polyimide film, for example, titanium oxide is added to make it red, and the film is irradiated with light emitted from a white light bulb that makes the tungsten filament red-hot. As a result, as shown in FIG.
... can be formed as shown in FIG. The manufacturing method involves, for example, potting a polyimide film containing a predetermined pigment on a selective surface of a semiconductor chip 4 on which one or more types selected from the group consisting of circuit components such as active elements, passive elements, and resistors are formed. After coating by the (POtting) method, the above-mentioned white bulb light is irradiated to form a discriminating mark 6 for a semiconductor element which changes color to a predetermined color.

Furthermore, the embodiment shown in FIGS. 6 and 7 will be explained. In this example, a semiconductor chip 4 is
This is a method of uniformly forming a plurality of semiconductor element discrimination marks 6 on the entire surface of a semiconductor substrate 2 on which... are formed. FIG. 6 is a sectional view showing the main part of the apparatus for carrying out this method, in which a semiconductor substrate 2 to be processed is placed on a stage 9, which consists of circuit components such as active elements, passive elements, and resistors. A polyimide film 7 that changes color when irradiated with light emitted from a white light bulb that makes a tungsten filament red-hot is applied to the top surface of a plurality of chips 4 on which one or more types selected from the group are formed. At this time, a pad (Pa
d) part, that is, a conductive region formed on the semiconductor substrate 2 for electrical connection to an impurity region formed by introducing and diffusing a predetermined impurity into a selective position of the semiconductor substrate and for electrical connection with other parts. Care must be taken not to coat layers consisting of sensitive metals.

When applying the polyimide film 7, a mask 10 is used that does not irradiate light on the good semiconductor chips 4 determined by the Daitsuta test, but allows light to shine on the defective semiconductor chips 4. Liquid crystal (not shown) is used as a material that can form a transparent part that changes to black when a signal is applied and becomes opaque to light. In the figure, the transparent part is shown as 11 and the opaque part is shown as 12. More mask 1
A light source 8 is installed opposite to the polyimide film 7 and emits light for changing the color of the polyimide film 7. On the other hand, the data obtained by the die sorter test is sent to the data converter 13 via a floppy disk or an online system to form an electrical signal, which is electrically connected to the mask 10.

FIG. 7 is a perspective view showing a state in which a plurality of semiconductor element discrimination marks 6 are formed on the semiconductor chip 4 using the mask 10. The stage 9 is equipped with a stepping motor (Stepp motor) so that the semiconductor substrate 2 can be moved in the X-Y direction.
ing Motor) 14 is attached and the mask 10 is attached.
A plurality of semiconductor element discrimination marks 6 . . . are formed on each semiconductor chip 4 at a time corresponding to the transparent portion 11 and the opaque portion 12 formed in the semiconductor chip 4 .

Note that a positioning step is required to place the semiconductor substrate 2 to be processed on the stage 9, but since it is not directly related to the present invention, a detailed explanation will be omitted. After this step, the data regarding the semiconductor substrate 2 to be processed is input, and a signal changed by the data converter 13 is applied to the liquid crystal placed on the mask 10 to create a predetermined pattern.
) is formed, and then the above-mentioned light emitting process is performed to complete the marking process.

[Effects of the Invention] According to the present invention, it is possible to eliminate variations in the formation position of the discrimination mark for semiconductor elements, thereby making it possible to make the size constant, and in addition, it is possible to shorten the drying time.

Furthermore, since it is possible to form a plurality of colors and different shapes, it is also possible to display the ranks of the characteristics of semiconductor elements. Furthermore, since processing can now be performed on a semiconductor substrate basis, productivity can be greatly improved compared to conventional processing on a semiconductor chip basis.

[Brief explanation of drawings]

FIG. 1 is a top view showing a state in which a semiconductor element identification mark is formed on a conventional semiconductor substrate, FIG. 2 is a top view of a semiconductor substrate subjected to the method of the present invention, and FIGS. 3 and 4 are diagrams showing the method of the present invention. A cross-sectional view and a perspective view showing an overview of the equipment used to perform the
FIG. 5 is a top view of a semiconductor substrate on which identification marks for semiconductor elements of different shapes and colors are formed by the method of the present invention, and FIGS. 6 and 7 are cross-sectional views showing essential parts of the method of the present invention using a mask. and a perspective view. DESCRIPTION OF SYMBOLS 1... Orientation flat part, 2... Semiconductor substrate, 3.
... Scripline, 4... Semiconductor chip, 5.6... Semiconductor element identification mark, 7... Polyimide film, 8... Light source, 9... Stage, 10...
...Mask, 11...Transparent part, 12...
Opaque part, 13... Data conversion part, 14... Stepping motor.

Claims (1)

[Claims] A film covering the top surface of one or more types selected from a group consisting of circuit components such as active elements, passive elements, or resistors built into a semiconductor substrate is exposed to light and changes color to determine whether the characteristics are good or bad. A method for forming an identification mark for a semiconductor device, characterized in that: