JP3290983B2 - Semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD OF THE INVENTION

 The present invention relates to a semiconductor device.

For example, when designing an aluminum wiring layer, its cross-sectional area is obtained by calculation so as to correspond to a required current density. However, in an actual manufacturing process, the cross-sectional area does not become the designed cross-sectional area but varies, and various problems occur when mounted in a package and used. In particular, semiconductor devices in recent years have become increasingly thinner with the introduction of fine technology and the speeding up of market needs, and management of the coverage of wiring layers has become an important point. Therefore, since the strictest portion of the coverage is the contact portion of the wiring layer, it is necessary to manage the coverage of the contact portion of the wiring layer.

[0003]

[Prior art]

Conventionally, in the management process, a chip from a certain part of the wafer is taken out, and the contact part of the wiring layer is scanned with a scanning electron microscope (SEM)
Observing from an oblique direction. In this case, since the cross section cannot be observed, the quality of the coverage is determined based on experience and intuition based on the degree of depression of the contact portion.

[0004]

[Problems to be solved by the invention]

Conventionally, since coverage management is performed based on experience and intuition, there is a problem in that the determination has too much error depending on the observer, environment, and the like, and accurate coverage management cannot be performed. Therefore, in order to eliminate such inconvenience,
Cutting the wiring layer contact part by cross section polishing and observing the cross section is also performed, but the work of gradually polishing the cross section from the end of the chip to the wiring layer contact part takes time, and IC There is a problem that chips are wasted to destroy the pattern forming portion.

An object of the present invention is to provide a semiconductor device capable of accurately and quickly observing coverage of a wiring layer and the like.

[0006]

[Means for Solving the Problems]

1A and 1B show the principle of the present invention. In FIG. 2A, reference numeral 33 denotes a coverage monitor section which is formed so as to cover both the scribe line 31 and the chip area 32 of the wafer 30. In this case, the coverage monitor section is formed so that the cross section of the monitor upper wiring layer appears by cutting the scribe line. On the other hand, in FIG. 3B, reference numeral 34 denotes a coverage monitor portion, in which the upper wiring layer for monitoring is formed in a patterned shape cut at the center of the contact hole. In this case, the coverage monitor is formed only on the scribe line 31 of the wafer 30.

In the above configuration, a scribe line is cut when a chip is obtained from a wafer. In the present invention, since the coverage monitor is formed so as to extend over both the scribe line and the chip region, and the cut of the scribe line causes the cross section of the monitor upper wiring layer to appear,
The cross section of the monitor upper wiring layer appears in the cross section of the scribe line without special cutting for coverage observation, and the coverage can be observed more accurately than the method of observing the dent state of the contact portion from an oblique direction, and the cross section It can be observed more quickly than polishing. Further, since the coverage monitor is formed in the scribe line and the chip area, coverage observation can be performed without destroying the IC pattern forming section (real device section).

[0008]

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 2 shows a plan view of the first embodiment of the present invention. In the figure,
11 to 16 are coverage monitor sections, and the monitor area of chip 2
The position is sequentially shifted from 2a to the monitor area 3a of the chip 3. Reference numeral 4 denotes a scribe line (cut area), which is provided adjacent to each chip 2, 3,... As shown in FIG. 3 which shows a schematic view of the entire wafer 5 (only 9 chips are shown for simplification of the drawing). Have been. The coverage monitoring units 11 to 16 include the cutting area 4 and are formed so as to cover the monitoring area 2a of the chip 2 or the monitoring area 3a of the chip 3.

Referring again to FIG. 2, the coverage monitor unit 1 of the monitor areas 2a and 3a
A transistor monitor (not shown) for monitoring the electrical characteristics of the transistor is provided on the left part excluding 1 to 16 as in the conventional example. 61,62,… is chip 2
Are the pads of the chip 3.

Here, the coverage monitors 11 to 16 are simultaneously formed in a normal aluminum wiring manufacturing process, and have a shape in which an upper aluminum layer and a lower aluminum layer are connected via a contact hole. 2 shows one of the coverage monitoring units 11 to 16 as shown in FIG. 4, and a lower aluminum layer 11 and a contact hole 12 a are provided on the wafer substrate 10. An isolation 12 and an upper aluminum layer (monitor aluminum pattern) 13 are formed.

When the chips 2, 3,... Are obtained from the wafer 5, the wafer 5 is cut at the cutting area 4. Here, in the coverage management step, when performing coverage observation, the cut surface is observed by SEM. Since the coverage monitor sections 11 to 16 are provided so as to extend over the monitor area 2a of the chip 2 or the monitor area 3a of the chip 3, when cut along the cutting area 4, the cut surface becomes as shown in FIG. Cross sections of the coverage monitor units 11 to 16 appear.

In this case, since the coverage monitor sections 11 to 16 are sequentially formed in the cutting area 4 with their positions shifted in the direction perpendicular to the display direction of the cutting area 4, the cutting accuracy of the cutting area 4 is not so high. Also, some cross sections of the coverage monitor section will surely appear. Coverage monitor section
Since 11 to 16 are formed at the same time in the normal aluminum wiring manufacturing process of the wafer 5, they can be a monitor unit for observing the coverage of the wafer 5.

According to the present invention, since the cross-sections of the coverage monitor sections 11 to 16 can be observed, the coverage can be determined more accurately than the conventional example in which the degree of depression of the contact portion is obliquely observed. The contact part is not polished in cross section for observation, but it is observed using the cut surface cut in the normal scribe process as it is, so it does not require much labor compared to the cross section polishing method In addition, a process abnormality can be quickly detected, and the process can be moved to the analysis process in a short time. Also, since the coverage of each of the chips 2, 3,... Can be accurately observed, the location of each chip on the entire wafer 5 can be accurately estimated, which is convenient for chip management. Further, since the coverage monitoring sections 11 to 16 are formed in the cutting area 4 and the monitoring areas 2a and 3a, coverage observation can be performed without destroying the IC pattern forming section (real device section), and chips are wasted. There is no.

FIG. 5 shows a plan view of a second embodiment of the present invention, in which FIG.
Portions having the same functions as those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 5, reference numerals 15 ₁ and 15 ₂ denote coverage monitors, which are formed over the chip 2 and the chip 3 via the cutting region 4 respectively. Coverage monitor 15 ₁ , 15
The cross section _{2 has} the shape shown in FIG. 4, and the coverage can be accurately observed by observing the cut surface that appears by cutting the cutting area 4 as in the first embodiment. Since the coverage monitor sections 15 ₁ and 15 ₂ are formed over the chip 2 and the chip 3, the cross sections of the coverage monitor sections 15 ₁ and 15 ₂ surely appear even if the cutting accuracy is not so high. be able to.

FIG. 6 shows a plan view of a third embodiment of the present invention, in which FIG.
Portions having the same functions as those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 6, reference numeral 20 denotes a coverage monitor unit.
An upper aluminum layer (aluminum pattern for monitoring) 21 and a contact hole 22 are formed in the cutting region 4.
a, composed of a lower aluminum layer 23. 22 is an isolation. The coverage monitor section 20 is formed simultaneously in the normal aluminum wiring manufacturing process. In particular, when forming the upper aluminum layer (monitor aluminum pattern) 21, the central portion of the contact hole 22a is different from the patterning of the normal upper aluminum layer. Is formed by patterning (that is, patterning that leaves only the satin portion).

Here, the contact holes 22 shown in FIG.
FIG. 7 shows a perspective view of the coverage monitor section 20 near a. 7, the same parts as those in FIG. 6 are denoted by the same reference numerals. Second
In the embodiment, since the upper aluminum layer (monitor aluminum pattern) 21 is formed in a patterned shape cut at the center of the contact hole 22a, the coverage of the upper aluminum layer 21 (see the arrow in FIG. 6) is provided in the contact hole 22a. ) Appears, and the coverage observation can be accurately performed using the SEM at the stage of the aluminum wiring manufacturing process without cutting the wafer as in the above-described first embodiment, and the number of processes does not increase. ,
Cost can be reduced. In addition, as in the first embodiment, it does not require much trouble as compared with the conventional example in which the cross section is polished, and does not need to destroy the IC pattern forming portion (actual device portion). The location can be accurately estimated.

[0018]

【The invention's effect】

As described above, according to the present invention, since the coverage monitor portion is formed so as to cover both the scribe line and the chip region, a cross section of the monitor upper wiring layer appears by cutting in a normal scribe process. Therefore, the coverage can be observed more accurately than in the conventional example, the observation can be performed more quickly than in the method of polishing the cross section, and the chip is not wasted.

[0019]

[Brief description of the drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a plan view of the first embodiment of the present invention.

FIG. 3 is a schematic view of an entire wafer according to the present invention.

FIG. 4 is a sectional view of a coverage monitor unit.

FIG. 5 is a plan view of a second embodiment of the present invention.

FIG. 6 is a plan view of a third embodiment of the present invention.

FIG. 7 is a perspective view of a coverage monitor according to a third embodiment.

[Explanation of symbols]

11-16,15 ₁ , 15 ₂ , 20,33,34… coverage monitor, 2,3… chip, 2a, 3a… monitor area, 4,31… scribe line (cut area), 5, 30 Wafer, 11, 23 Lower aluminum layer, 12, 22 Isolation, 12a, 22a Contact hole, 13, 21 Upper aluminum layer (aluminum pattern for monitor) (upper wiring layer for monitor) ), 32 ... chip area

Continuation of front page (56) References JP-A 1-2232748 (JP, A) JP-A 64-59231 (JP, A) JP-A 63-234544 (JP, A) JP-A 63-208252 (JP JP-A-63-107037 (JP, A) JP-A-1-123430 (JP, A) JP-A-59-107532 (JP, A) JP-A-2-270342 (JP, A) JP-A-2-235356 (JP, A) JP-A-63-278242 (JP, A) JP-A-59-46042 (JP, A) JP-A-2-129730 (JP, A) U) Tokuhyo Sho 61-501738 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/66

Claims (3)

(57) [Claims] 1. A semiconductor device comprising a coverage monitor of a wiring layer formed so as to extend over both a scribe line and a chip area of a semiconductor substrate, wherein the coverage monitor is configured to cut the scribe line to cut the scribe line. A semiconductor device formed in a shape in which a cross section of a wiring layer appears. 2. The semiconductor device according to claim 1, wherein a plurality of said coverage monitors are formed by sequentially shifting their positions in a direction perpendicular to a longitudinal direction of said scribe line. 3. The semiconductor device according to claim 1, wherein said coverage monitor is formed over two adjacent chip regions via a scribe line.