JPS6373535A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To make it possible to carve a marking trace having a specified dimension even with a laser marker equipment of small power capacity, and achieve the stable optical reading of a defective unit element region, by providing each of the unit element region on a wafer with a metal film pattern for wiring and a silicon oxide film in the manner in which they are locally mixed and concentrated in every small area unit. CONSTITUTION:On a silicon oxide film 2 as an insulating film, a metal film pattern 3 for wiring is formed in the manner in which the metal film pattern 3 and the silicon oxide film 2 are locally concentrated in every small area unit and mixed so as to constitute a slit shape. In the case of such a structure, when the metal film pattern 3 in a defective unit element region is irradiated by a laser ray, its power is converted to heat on each metal film pattern 3 on a pellet surface. As the pattern width is narrow, the heat is not easily dissipated into the peripheral part but makes the oxide film 2 in the vicinity of each metal film pattern 3 melt together to form a marking trace 4. In a selecting process, an optical checking equipment discriminates the marking trace 4 and determines a defective.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of manufacturing a semiconductor device using a thermal power device.

[Conventional technology]

Conventionally, since only good pellets are used in the IC assembly process, defective pellets are removed in advance.

The defective pellets are removed by forming a pattern of each unit element area (hereinafter simply referred to as unit element area) that integrates semiconductor elements to achieve one function and is surrounded by scribe lines in the wafer state before being separated into pellets. Laser marking is performed on the surface of the unit element, and then it is sorted and removed by optical means. However, there are no particular rules regarding which pattern and which area on the surface of the unit element area to be engraved when laser marking is performed. Instead, small markings were placed at appropriate locations for each variety.

For example, markings are made on patterns with wide wiring widths such as power supply lines, or markings are made on patterns with narrow wiring widths such as signal lines.

When marking the former pattern with a thick wiring width,
Since the thermal conductivity of metal materials is high, even if the energy of the laser beam is converted into heat, it is dissipated into the surrounding area, resulting in a small marking mark.

The latter case of marking a pattern with a small wiring width will be explained with reference to FIGS. 2(a) and 2(b).

FIGS. 2(a) and 2(b) are a partial plan view and a sectional view taken along the line Y-Y' of the unit element region, respectively.

Silicon oxide W with a thickness of approximately 1 μm is deposited on the semiconductor substrate 11.
A12 is formed, and a metal layer pattern 13 having a thickness of about 2 μm and serving as a signal line is formed thereon. here,
When the unit element region is determined to be a defective product, a laser beam is irradiated from a laser marker device (not shown) to leave a marking mark 14 and break the pattern 13. The actual irradiation area of the semiconductor substrate 11 with the laser beam is an irradiation area 15 with a diameter of about 200 μm as shown by the dotted line, but since the silicon oxide film 12 is transparent, the laser beam passes through it.

In short, the laser beam irradiated onto areas other than the marking trace 14 is absorbed by the semiconductor substrate 11 below, and the marking trace 14 becomes smaller. Therefore, when marking with a laser beam of normal energy, an area where signal lines are appropriately concentrated is selected and marked for each product type.

Next, when removing the marked defective unit element area mentioned above, a method of optically detecting the marking trace is beginning to be adopted, but at the current stage, the entire surface of the defective unit element area is identified. However, the presence or absence of markings is only determined in a limited small area.

[Problem that the invention seeks to solve]

The above-mentioned conventional marking for removing defective unit element regions has technical problems with the thermal conductivity of the pattern and the light transmittance of the silicon oxide film. However, there is a drawback that there is uncertainty when optically detecting marking traces.

In particular, in master slice integrated circuits where the diffusion pattern is common and only the wiring pattern is different, it is desirable to make the laser marking position the same for all products. The wiring structure differs depending on the product type, and if the marking position is fixed, depending on the product type, there may be a power line there or there may be only an insulating film. In such a case, as mentioned above, the size of the marking becomes small and unstable,
The drawback is that marking is impossible with a laser marker device of normal power.

The purpose of the present invention is to perform the conventional marking on defective unit element regions to distinguish them from good products and to remove them.
It is an object of the present invention to provide a method for manufacturing a semiconductor device, which can increase the size of marking even when using a laser marker device of normal power, and can reliably remove defective unit element regions.

[Means for solving problems]

A method for manufacturing a semiconductor device according to the present invention includes the steps of: coating an insulating film on a semiconductor substrate having a plurality of unit element regions surrounded by scribe lines and integrating semiconductor elements to achieve one function; A process of forming a metal film pattern for wiring and the insulating film in a locally mixed and concentrated manner in small area units; The method includes a step of marking by irradiating a laser beam, and a step of optically identifying the marking trace and selecting it as a defective product.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1(a) and 1(b) are a plan view of a part of a defective unit element region and x-x' for explaining one embodiment of the present invention.
FIG.

In FIGS. 1(a) and 1(b), silicon oxide is formed as an insulating film on a semiconductor substrate 1! 2 is the same as the conventional method, but in this embodiment, this silicon oxide film 2
A metal film pattern 3 used for wiring is locally concentrated in small area units on top, and the metal film pattern 3 and silicon oxide film 2 are formed in a slit-like manner.

With such a structure, when the metal film pattern 3 in the defective unit element region is irradiated with a laser beam, the power is converted into heat on each metal film pattern 3 on the pellet surface.

Since the width of the pattern is narrow, the heat is not easily dissipated to the surroundings, and melts the silicon oxide film 2 in the vicinity of each metal film pattern 3, thereby creating a marking mark 4.

Next, in a sorting process, an optical determination device (not shown) identifies the marking traces 4 in the unit element area and determines the product to be defective.

In this way, if a large marking trace 4 is provided on a defective unit element region, it can be easily identified and determined as a defective product by a normal optical judgment device in the sorting process, so that the separated defective unit element region can be easily identified and judged as a defective product. This also eliminates the problem of treating products as non-defective products.

In addition, although the metal film pattern explained in the said Example was demonstrated as the metal film pattern for wiring, it may also be used as the signal line of an integrated circuit.

Further, the metal film pattern may be scattered not only in a linear pattern but also in a dotted pattern.

In short, it is sufficient that the metal film pattern and the silicon oxide film are locally mixed and concentrated in small area units compared to the area irradiated with the laser beam.

〔Effect of the invention〕

As explained above, the present invention provides a small capacitance by providing a wiring metal film pattern and a silicon oxide film locally mixed and concentrated in small area units in each unit element region on a wafer. Even with a laser marker device of high power, a marking trace of a constant size can be engraved, and there is an effect that a method of manufacturing a semiconductor device can be obtained that can achieve stable optical reading of a defective unit element region.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are a plan view of a part of a defective unit element region and x-x' for explaining one embodiment of the present invention.
2(a) and 2(b) are a plan view and a sectional view taken along YY' line of a part of a conventional defective unit element region. 1... Semiconductor substrate, 2... Silicon oxide film, 3...
・Metal film pattern, 4...marking traces. Figure 1

Claims (1)

[Claims] A step of coating an insulating film on a semiconductor substrate having a plurality of unit element regions surrounded by scribe lines and integrating semiconductor elements to achieve one function, and forming a metal film pattern for wiring on the insulating film and the insulating film. a step of forming the metal film pattern locally mixed and concentrated in small area units; a step of irradiating and marking the metal film pattern with a laser beam from a laser marker device only in the case of the defective unit element region; A method for manufacturing a semiconductor device, comprising the step of optically identifying marking marks and selecting them as defective products.