JPH03180046A - Semiconductor-element observing apparatus - Google Patents

Abstract

PURPOSE:To make it possible to observe the inside of a semiconductor element through both upper and rear surfaces by holding the semiconductor element with a semiconductor-element holding tool, setting the element between a metal microscope and an infrared-ray microscope, aligning the focal points to the inside of the semiconductor element, observing the inside through both surface, and displaying the images. CONSTITUTION:A semiconductor-element holding tool for holding a semiconductor element 50 is provided between an objective lens 13 of a metal microscope 10 and an objective lens 23 of an infrared-ray microscope 20. The optical axis of the metal microscope 10 always agrees with the optical axis of the infrared-ray microscope 20. Therefore, the metal microscope 10 and the infrared-ray microscope 20 always observe the same point of the semiconductor element 50 through both upper and rear surfaces. The image of the inside of the semiconductor element 50 which is magnified in the metal microscope 10 is inputted into an image processing part 32 from a video camera 31 and displayed on a first display part 33. Meanwhile, the image of the inside of the semiconductor element 50 which is magnified in the infrared-ray microscope 20 is inputted into a mirror-image processing part 42 from a video camera 41, and mirror image processing is performed. The mirror image is displayed on a second display part 43. Thus, the inside of the semiconductor element 50 is observed through both upper and rear surfaces at the same time.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an apparatus for observing the inside of a semiconductor element such as an LSI, and particularly to a semiconductor element observation apparatus capable of simultaneously observing the inside of a semiconductor element such as an LSI.

<Prior art> High-density semiconductor devices use multilayered internal wiring made of aluminum, etc., so that the wiring exposed on the surface, that is, the upper layer wiring and the lower layer where there is no upper layer wiring, is used in high-density semiconductor devices. Only the wiring can be observed by visible light from the surface.

Therefore, the wiring in the lower layer, which cannot be observed using visible light from the front side, is observed using an infrared microscope from the back side.

The back surface of the semiconductor element is mirror-polished and observed from the back surface using an infrared microscope.

For observing semiconductor devices using an infrared microscope, see Utilization of Infrared Microscope for Internal RFC Failure Analysis J at the 19th Reliability and Maintainability Symposium.
(See P, 261-266).

<Problems to be Solved by the Invention> However, the conventional semiconductor device observation apparatus described above has the following problems.

(2) Conventional semiconductor device observation devices can only observe semiconductor devices from one side, so detailed observation takes a lot of time.

■It is impossible to observe middle-layer wiring and lower-layer wiring covered by upper-layer wiring with a metallurgical microscope.

■The image observed from the back side becomes a mirror image, making it difficult to observe.

■It takes time to peel off the protective film and upper layer wiring due to chemical treatment.

(2) There is no semiconductor device holder that allows semiconductor devices to be observed from both the front and back sides.

(2) When observing a semiconductor element whose chip is sealed in resin by polishing it from the back side, the bonding wires and lead frame are also polished, making it impossible to observe the operating state.

The present invention was devised in view of the above circumstances, and an object of the present invention is to provide a semiconductor device observation apparatus that eliminates the plurality of problems described above.

<Means for Solving the Problems> A semiconductor device observation device according to the present invention is a semiconductor device observation device that simultaneously observes the inside of a semiconductor device from both the front and back sides, and is a semiconductor device observation device that simultaneously observes the inside of a semiconductor device from the front and back sides, and is a metallographic microscope that magnifies the inside of a semiconductor device from the surface. , a first display section that displays an enlarged image of the metallurgical microscope; an infrared microscope that enlarges the inside of the semi-quadram element from the back side; a mirror image processing section that makes the enlarged image of the infrared microscope a mirror image; a second display section that displays an enlarged image;
A semiconductor element holder is provided for holding a semiconductor element between a metallurgical microscope and an infrared microscope, and the optical axes of the metallurgical microscope and the infrared microscope are aligned.

Action> A semiconductor element is held in a semiconductor element holder and placed between a metallurgical microscope and an infrared microscope.

Focusing on the inside of each semiconductor element, the inside is observed from both sides.

An image observed from the front surface, that is, an image observed using a metallurgical microscope, is displayed on the first display section, and an image observed from the back surface, that is, an image observed using an infrared microscope is displayed on the second display section after undergoing mirror image processing.

<Example> Hereinafter, an example according to the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a semiconductor device observation device according to an embodiment of the present invention, FIG. 2 is a sectional view showing an example of a semiconductor device observed by this semiconductor device observation device, and FIG. 3 is a cross-sectional view of this semiconductor device observation device. An explanatory diagram illustrating observation of a semiconductor element using an element observation device, FIG. 4 is a plan view of a wafer stand which is a type of semiconductor element holder, FIG. 5 is a sectional view taken along the line A-A in FIG. 4, and FIG. 7 is a plan view of a package which is a type of semiconductor element holder, FIG. 7 is a sectional view taken along the line B--B in FIG. 6, and FIG. 8 is an explanatory diagram illustrating pre-processing of a semiconductor element using the package.

Note that the semiconductor element 50 observed with the semiconductor element observation apparatus according to this embodiment is made of a Si substrate 57, as shown in FIG.
It is assumed that a lower layer wiring 55, a middle layer wiring 54, and an upper layer wiring 53 are sequentially laminated on top of the substrate, and the upper layer wiring 53 is covered with an insulating film 56. Furthermore, it is assumed that two lower layer wirings 55 and two middle layer wirings 54 are formed toward the front and back sides of the paper.

The semiconductor device observation apparatus according to this embodiment has a semiconductor device 50
This semiconductor device observation device simultaneously observes the inside of a semiconductor device 50 from both the front and back sides, and includes a metallurgical microscope 10 that magnifies the inside of a semiconductor device 50 from a surface 51, and a first display section 33 that displays an enlarged image from this metallurgical microscope 10. , an infrared microscope 20 that magnifies the inside of the semiconductor element 50 from the back surface 52, a mirror image processing section 42 that makes the enlarged image from the infrared microscope 20 a mirror image, and a second display section 43 that displays the mirror image processed enlarged image. , a semiconductor element holder that holds the semiconductor element 50 between the metallurgical microscope 10 and the infrared microscope 20.

A video camera 31 is set in place of an eyepiece in a metallurgical microscope IO that magnifies the inside of the semiconductor element 50 from the surface 51 using visible light.
An enlarged image of the interior is displayed on the first display section 33. This metallurgical microscope 10 includes a light source 11,
It has a half mirror 12 that reflects the light source light L1 from the light source U toward the objective lens 13, and is configured so that the reflected light L2 from the semiconductor element 50 is incident on the video camera 31.

An infrared microscope 20 that magnifies the inside of the semiconductor element 50 from the back surface 52 using infrared rays R is equipped with a video camera 41 instead of an eyepiece, and an enlarged image of the inside of the semiconductor element 50 from the back surface 52 is displayed on a second display. It is configured to be displayed in the section 43. The infrared microscope 20 is basically the same as a normal optical microscope, but it has an infrared filter 22 built-in, and the infrared rays R that are selectively transmitted through the infrared filter 22 are used to detect the object to be observed (in this case, , the semiconductor element 50 corresponds to this). The infrared microscope 20 can observe the inside of an object by focusing on the inside of the object. Further, the wavelength band of the infrared ray R can be arbitrarily changed by replacing the infrared filter 22.

Objective lens 13 of metallurgical microscope 10 and infrared microscope 20
A semiconductor element holder for holding the semiconductor element 50 is installed between the objective lens 23 and the objective lens 23 .

The optical axes of the metallurgical microscope 10 and the infrared microscope 20 always coincide. Therefore, the metal microscope b110 and the infrared microscope 20 always observe the same point of the semiconductor element 50 from both the front and back sides.

An image of the interior of the semiconductor element 50 magnified by the metal 'RTR4 microscope 10 is captured by the image processing section 32 from the video camera 31 and displayed on the first display section 33.

On the other hand, the image of the interior of the semiconductor element 50 magnified by the infrared microscope 20 is captured from the video camera 41 to the mirror image processing section 42, where it undergoes mirror image processing, and the mirror image is displayed on the second display section 43. Note that mirror image processing refers to converting an original image into an image that looks like it is reflected in a mirror.

Next, a wafer stand 60, which is a type of semiconductor element holder, will be explained with reference to FIGS. 4 and 5.

The wafer stand 60 is used when observing the semiconductor device 50 in the state of a wafer 70, and has a half-doughnut-shaped front part 61 and a hinge 63 similar to the front part 61. and a rear part 62 which is attached so as to be openable and closable, and has a generally donut shape as a whole. Grooves 611 and 621 for holding and holding the peripheral edge of the wafer 70 are formed in the inner edges of the front part 61 and the rear part 62, respectively. The front part 61 and the rear part 62 are the wafer 7
0 is held in place by the locking fittings 64. This wafer stand 60 is installed between the metallurgical microscope 10- and the infrared microscope 20 of the semiconductor device observation apparatus, and can be replaced as appropriate depending on the size of the urchin/'%70 to be observed. Note that 65 in the drawings indicates a metal fitting for fixing the wafer stand 60 to the metallurgical microscope 10 or the like. The wafer table 60 is capable of automatically or manually moving the wafer 70, and the field of view for observation can be changed.

Next, pretreatment when observing the semiconductor element 50 in the state of the wafer 70 will be described.

The back surface 72 of the wafer 70 is polished to a mirror surface with sandpaper having a roughness of #500 to #1000 and a lapping sheet coated with diamond powder having a roughness of #1000 to #10,000. Note that during this polishing, the surface 71 is protected with a resist film.

After polishing the back surface 72, the resist film is removed and the wafer 70 is cleaned and dried.

The wafer 70 that has been subjected to such pretreatment is placed on the wafer stand 60.
Fixed to. At this time, the front surface 71 of the wafer 70 faces the metallurgical microscope 10 and the back surface 72 faces the infrared microscope 20.

Next, a pan cage 80, which is a type of semiconductor element holder and is used when observing the semiconductor element 50 in the chip or double state, is shown.
I will explain about it. Note that, hereinafter, the chip-shaped semiconductor element 50 will be referred to as a chip 90.

Since the chip 90 is smaller than the wafer 70, it cannot be held on something like the wafer stand 60.

Therefore, a package 80 as described below is used.

The pan cage 80 has a bottom shape made of ceramic, and has an upper part 81 with a stepped opening 811 in the center;
The lower part 82 is attached to the upper part 81 so as to close the opening 811 from below.

In the center of the lower part 82, there is a depression 8 in which a chip 90 is fixed.
21 is formed. This depression 821 corresponds to the opening 8
The chip 9 corresponds to 11 and is fixed in the recess 821.
0 will be exposed through the opening 811. In addition, the upper part 8
A plurality of leads 812 are provided on both sides of the chip 1 in the longitudinal direction, and are connected to electrode portions (not shown) of the chip 90 using bonding wires 84 made of aluminum or the like as necessary.

Next, a description will be given of pre-processing when observing the chip 90 using this package 80 with a semiconductor device observation device.

A gap 81 created between the chip 90 and the opening 811 after the chip 90 is attached to the recess 821 with conductive paste.
3 is injected with resin 83 to fix the chip 90 to the package 80. Note that the corresponding chip 90 and the lead 812 are connected with the bonding wire 84 as necessary to put the chip 90 into an operable state (see FIG. 8(a)).

Remove the lower part 82 of the package 80 from the upper part 81,
The back surface 92 of the chip 90 is exposed (see FIG. 8(b)).

Back side 92 of chip 90 protruding from the back side of upper part 81
was polished to a mirror surface using sandpaper with a roughness of #500 to #1000 and a wrapping sheet with a roughness of #1000 to #10,000 in the same manner as described above (Figure 8 (C)).
reference).

The chip 90 that has been pretreated as described above is set together with the package 80 between the metallurgical microscope 10 and the infrared microscope 20 of the semiconductor device observation apparatus. At this time, chip 90
The front surface of the chip 90 faces the metallurgical microscope 10, and the back surface 91 of the chip 90 faces the infrared microscope 20.

Adjusting the focus of the metallurgical microscope 10 and the infrared microscope 20,
Enlarged images of the front surface 92 and back surface 91 of the chip 90 are displayed on the first display section 33 and the second display section 43 for observation.

Next, a third observation will be made regarding the case where a semiconductor element 50 having a structure as shown in FIG.
This will be explained with reference to the figures.

The semiconductor element 50 is set with its front surface 51 facing the metallurgical microscope 10 and its back surface 52 facing the infrared microscope 20.

The inside of the semiconductor element 50 magnified by the metallurgical microscope 10 is displayed on the first display section 33 via the video camera 31 and the image processing section 32 as shown in FIG. 3(a).

That is, the upper layer wiring 53, the middle layer wiring 54 and the lower layer wiring 55 that are not covered by the upper layer wiring 53 are displayed. Note that 58 in the drawings indicates a through hole.

The infrared microscope 20 examines the inside of the semiconductor element 50 as shown in FIG.
Expand as in b). That is, it is possible to observe the middle layer wiring 54 and the lower layer wiring 55 covered by the upper layer wiring 53, which were not observable with the metallurgical microscope IO. However, it is a mirror image of what was observed with the metallurgical microscope 10. Therefore, the second display section 43 displays an image subjected to mirror image processing by the mirror image processing section 42, that is, an image as shown in FIG. 3(C).

Note that the semiconductor element holder in the semiconductor element observation apparatus is not limited to the wafer stand 60 and package 80 described above. Various selections can be made depending on the shape of the semiconductor element 50, which is the object to be observed.

<Effects of the Invention> The semiconductor device observation apparatus according to the present invention includes a metallurgical microscope that magnifies the inside of a semiconductor device from the front surface, a first display section that displays an enlarged image of the metallurgical microscope, and a first display section that magnifies the inside of the semiconductor device from the back surface. A semiconductor element is held between an enlarging infrared microscope, a mirror image processing section that makes an enlarged image of the infrared microscope a mirror image, a second display section that displays an enlarged mirror image, and a metallurgical microscope and an infrared microscope. Since the optical axes of the metallurgical microscope and the infrared microscope are aligned, the inside of the semiconductor element can be observed from both the front and back sides at the same time.

Therefore, the parts that were impossible to observe from one side,
For example, lower layer wiring covered by upper layer wiring can be observed. Moreover, the time required for this observation can be shortened by observing from both the front and back sides.

In addition, since a semiconductor element holder is provided to hold the semiconductor element between the metallurgical microscope and the infrared microscope, it is possible to observe the semiconductor element from both the front and back sides simultaneously, and to observe the chip-shaped semiconductor element in its operating state. It is also possible to do so.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a semiconductor device observation device according to an embodiment of the present invention, FIG. 2 is a sectional view showing an example of a semiconductor device observed by this semiconductor device observation device, and FIG. 3 is a cross-sectional view of this semiconductor device observation device. An explanatory diagram illustrating observation of a semiconductor element using an element observation device, FIG. 4 is a plan view of a wafer stand which is a type of semiconductor element holder, FIG. 5 is a sectional view taken along the line A-A in FIG. 4, and FIG. 7 is a plan view of a package which is a type of semiconductor element holder, FIG. 7 is a sectional view taken along the line B--B in FIG. 6, and FIG. 8 is an explanatory diagram illustrating pre-processing of a semiconductor element using the package. 10...Metal microscope, 20...Infrared microscope, 42
...Mirror image processing section, 33...First display section, 43...
Second display section, 50... Semiconductor element, 51... (Semiconductor element) front surface, 52... (Semiconductor element) back surface,
60... Wafer stand (semiconductor element holder), 80...
Package (semiconductor element holder) diagram

Claims (1)

[Claims] (1) A semiconductor device observation device that simultaneously observes the inside of a semiconductor device from both the front and back sides, which includes a metallurgical microscope that magnifies the inside of the semiconductor device from the surface, a first display section that displays an enlarged image of the metallurgical microscope, and a semiconductor device. an infrared microscope that magnifies the inside of the infrared microscope from the back side, a mirror image processing section that makes the enlarged image of the infrared microscope a mirror image, a second display section that displays the mirror image processed enlarged image, and an infrared microscope that is connected between the metallurgical microscope and the infrared microscope. 1. A semiconductor device observation apparatus comprising a semiconductor device holder for holding a semiconductor device, wherein the optical axes of the metallurgical microscope and the infrared microscope are aligned.