JPH0516664B2 - - Google Patents

Description

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

[Conventional technology]

Conventionally, only good pellets are used in the IC assembly process, so defective pellets are removed in advance. This removal of defective pellets involves integrating semiconductor elements to achieve a single function in the wafer state before cutting into pellets, and forming each unit element area (hereinafter simply referred to as unit element area) surrounded by scribe lines. Laser marking is performed on a pattern, and it is selected and removed by optical means. However, when laser marking is performed, there are no particular rules regarding which pattern and which area on the surface of the unit element area is to be engraved. Not,
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.

In the former case, when marking a pattern with a wide wiring width, the thermal conductivity of the metal material is high, so even if the energy of the laser beam is converted into heat, it is dissipated to 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. 2a and 2b.

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

A silicon oxide film 12 with a thickness of approximately 1 μm is formed on a semiconductor substrate 11, and a metal layer pattern 13 with a thickness of approximately 2 μm, which will serve as a signal line, is formed thereon. Here, when the unit element area is determined to be defective, a laser beam is irradiated from a laser marker device (not shown) to mark the marking mark 1.
4 and break pattern 13. The actual irradiation area of the laser beam on the semiconductor substrate 11 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, and the marking marks are small regardless of the size of the pattern. There is a drawback that there is uncertainty when detecting marking traces optically.

In particular, in a master slice type integrated circuit in which a common diffusion pattern is provided and only the wiring pattern is different, it is desirable to make the laser marking position the same for all products.
However, the wiring structure of current integrated circuits differs depending on the product type, and when the marking position is fixed, depending on the product type, there may be a power supply line there or only an insulating film. In such a case, as described above, the size of the marking becomes small and unstable, and there is a drawback that marking cannot be performed using a laser marker device of normal power.

It is an object of the present invention to increase the size of markings and to ensure that defective areas are marked even when using a laser marker device with normal power, in order to distinguish such defective unit element areas from conventional markings and remove them from non-defective units. An object of the present invention is to provide a method for manufacturing a semiconductor device in which a unit element region is removed.

[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. 1a and 1b are a plan view of a part of a defective unit element region and an X
-X' line sectional view.

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

With this structure, when the metal film pattern 3 in the defective unit element region is irradiated with a laser beam, the power is equal to that of each metal film pattern 3 on the pellet surface.
is converted into heat at the top. 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 the sorting step, the marking traces 4 in the unit element area are identified by an optical determination device (not shown) and determined to be a defective product.

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.

Note that although the metal film pattern described in the above embodiment was explained as a metal film pattern for wiring,
It may also be used as a 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 wiring metal film pattern and a silicon oxide film in each unit element region on a wafer so that they are locally mixed and concentrated in small area units, thereby achieving low capacity power. Even with a laser marker device, marking traces of a constant size can be engraved, and there is an effect that a method for manufacturing a semiconductor device can be obtained in which stable optical reading of defective unit element regions can be achieved.

[Brief explanation of the drawing]

FIGS. 1a and 1b are a plan view of a part of a defective unit element region and an X
-X' exclusive cross-sectional view, and FIGS. 2a and 2b are a plan view and a YY' line cross-sectional view of a part of a conventional defective unit element region. 1...Semiconductor substrate, 2...Silicon oxide film, 3
...Metal film pattern, 4...Marking traces.

Claims (1)

[Claims] 1. A step of coating an insulating film on a semiconductor substrate having a plurality of unit element regions surrounded by scribe lines, which integrates semiconductor elements to achieve one function, and coating a metal film pattern for wiring on the insulating film with the a step of forming an insulating film locally mixed and concentrated in small area units; a step of irradiating and marking the metal 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 the marking trace and selecting it as a defective product.