JPS59154313A - Apparatus for measuring distance and slanting angle - Google Patents

Abstract

PURPOSE:To obtain the sufficiently high precision of the titled apparatus by providing the light source irradiating the beam and the lense condensing the reflected beam and detecting the shifting of image-forming positions of optical system, etc. obtaining the divided beams for two directions. CONSTITUTION:The beam emitted from the light sources S1, S2 have the spot diameters of about from several 10 to several 100mumphi at reflecting surfaces R1, R2. The lense L is arranged so that an optical axis is made to coincide with a reflected beam. A beam splitter 2 for dividing is provided at b1 distance from the lense L between the lense L and two-dimensional position sensor 1. In the position measurement, e.g. the spot image of the surface R1 is condensed by the lense L and is formed images at a position P2 of a one-dimensional sensor 3 as the reflected light of the splitter 2. In such a way, the sufficiently high precision measurement can be performed by detecting the shift of these image-forming positions.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for measuring the position and parallelism of a plate having a minute area, such as a semiconductor integrated circuit chip.

2. Description of the Related Art Semiconductor integrated circuits (IC, LSI, etc., hereinafter simply abbreviated as IC) are generally mounted by mounting a semiconductor chip on a mounting base made of ceramic or the like.

In recent years, many ICs with multiple arrays of photo-sensing elements have been manufactured, such as image 7-→no ICs, and it is necessary to strictly control the parallelism when mounting semiconductor chips on a mounting stand. is occurring.

1. For example, in a solid-state imaging device using a CCD (charge-coupled differential) element, the CCD chip is 5 x 5.
In addition to using a plate with a micro-area as small as my size, and in order to attach the filter parallel to the chip, which is about 10 mm apart from the surface of the chip, in the preparation stage before pasting, A measurement system for two-axis direction control, which is placed several tens of millimeters away from the front, is essential for the laminating apparatus.

Conventionally, inclination measurement and distance measurement have been used to measure the parallelism of a plate such as an IC chip and its surface with irregularities of several microns and the distance from a reference point. There is no measurement method that can perform both at the same time.

1. Conventionally, the only way to measure distance and inclination was to use separate devices and perform them sequentially.

However, in the OJ collimator conventionally used for measuring inclination, it is essential that the surface to be measured be able to reflect specularly, so if the surface has irregularities, the accuracy rl decreases.

In addition, distance measurement can be performed by irradiating the surface to be measured with a sub-I beam and converging the reflected light and reading it with a position sensor, but if the parallelism of the surface to be measured is not maintained. cannot make accurate measurements.

As described above, the conventional method of measuring distance and inclination separately has the drawback that not only the accuracy actually decreases, but also the measurement is time-consuming in practical terms3. - It was developed in consideration of the points mentioned above, and it is possible to simultaneously measure the distance from the reference surface and the normal slope of a plate with a small area, and to measure the distance and slope angle with high accuracy without contacting the surface to be measured. The purpose is to provide equipment.

An embodiment of the present invention will be described below.

The light source (S) is, for example, a light emitting diode, a laser diode, a gas laser, or the like that generates a highly focused beam.

One of the reflective surfaces (ltl) and (R12) is a surface to be measured such as a 1C chip, and the other is an imaginary reference surface.

The beam from the light source (S) is reflected by the reflecting surface (R12), (rt
+) has a spot diameter of, for example, several tens to several tens of millimeters.

The lens (L) is a convex lens placed at a distance a from the reflective surface (R1), which is a virtual reference surface, with its optical axis aligned with the reflected beam. It can also be used. , in the focal plane of this lens (L), that is, 1//zu (L
), an area image sensor (1) consisting of a plurality of photoelectric conversion elements regularly arranged vertically and horizontally, or a two-dimensional position sensor (1) equivalent thereto, is located at the focal length f of the lens (L). The optical axis of the lens is aligned with the optical axis of the lens.

A splitting beam splitter (2) is provided between the lens (L) and the two-dimensional position sensor (1).

The reference reflecting surface (R
3) is imaged on the surface (1 of R2 from the splitter (2)
A dimensional position sensor (3) is arranged.

This one-dimensional position sensor (3) is a linear image cell in which a plurality of photoelectric conversion elements are linearly arranged or something equivalent thereto, and both cells (li+31) are irradiated with spot light. The position of the sensor can be detected depending on the position of the sensing element.

In the device of the present invention configured in this way, the one-dimensional position sensor (3) measures the distance between the reflecting surfaces (a+) (R, 2) at the same time, and the two-dimensional position sensor (1)
The parallelism between the reflective surfaces (R1) and (R2) can be measured.

That is, in position measurement, a spot image of a reflective surface (tortoise) that forms a reference surface is focused by a lens (j), and is sent to a one-dimensional position sensor (3) as reflected light from a splitting beam splitter (2). The image is formed at the P2 position.

On the other hand, when a spot image is formed on the surface to be measured (R2),
Similarly, it passes through the lens (T, ) and the splitting beam splitter (2), and is then transferred to the one-dimensional position /'+1-(310
The image is formed at the P2' position.

Therefore, first, measure the light from the reference surface (R1) to determine the P2 position of the one-dimensional position sensor (3), and then move the surface to be measured (R2) near the reference surface (sticker). If you bring it to the top and give it light, the one-dimensional position above → t-(3) P
It can be tied to the 2' position.

By using this relationship, the distance between the reflective surface (R2) and the surface to be measured can be calculated using the reflective surface (R+) as a reference.

In other words, the distance between (R1) and (n, □) is d, (P2)
Let the distance between and (P2') be X2. Reference reflector of light source (R1)
Let α be the angle of incidence on (a'+)(
A relational expression is derived based on FIG. 2, which shows the R2) part enlarged.

b, 1 to l)2 Here, if the magnification of this optical system is m (= -), then January and α are the given values, and θ is determined by the measurement method described later, By measuring the distance X2 with the one-dimensional sensor (3), CI, that is, the distance from the reference position to the position where the object to be measured is placed can be determined.

Next, the slope (θ) measurement will be explained.

The light rays (approximately parallel rays) emitted from the light source (S) K pass through the reflective surface (R+) (R2) and are placed at the focal point of the lens (L) (i.e., at a distance #If from the lens (I)). The focus is on the two-dimensional position sensor fil.

The image formation point of the ray that passed through the reference reflective surface (R,) is 2
Assuming that the origin (Pi) of the dimensional position sensor 11) surface is the imaging point from the reflective surface (R2), which is the surface to be measured, the reflective surface (R
1) When (R2) is parallel, they match at PI, and when the reflecting surface (R2) is tilted, the input point is on the two-dimensional position sensor 5 (j) depending on the tilt angle and direction. Therefore, P,' which is shifted vertically and horizontally occurs. 7 The position of this P1' is
If the reflective surface (R2) is tilted by θ as shown in Figures 1 and 2, the tilt of the light rays incident on the lens (L) is 2.
θ, P 1P (' = X H'-' f ta
1 which becomes n 2θ, therefore, Sθ can be found.

Therefore, first, shine light on the reference reflective surface (rt +), determine the position (PI) of the two-dimensional sensor (1),
Next, the object to be measured (R2) is irradiated with light and the position (P white) is detected.

In this way, the splitting beam sinter (2) is placed behind the lens (L), and the one-dimensional position sensor (3) and the two-dimensional position sensor (1) are used to simultaneously measure the position relative to the reference plane. Distance and slope can be measured.

In the above embodiment, the lens (I7) and the beam splitting i
The reflected beam is focused by an optical system consisting of an IJ footer 2) to obtain split beams in two directions, but the lens (L) can be made into a composite lens system of multiple lenses to shorten the focal length. Therefore, the device size can be made compact.

′-! In addition, as a beam detection means, one-dimensional position sensor/→
Both (3) and the two-dimensional position sensor (1) can be constructed from an image sensor or the like in addition to a continuous output analog sensor.

However, sensors (1) and (3) are not necessarily limited to two and one dimensional ones, respectively.
For 1), a one-dimensional surface may be used as long as the reflective surface (R2) to be measured is tilted in only one direction, as shown in the diagram. . (Generally, a two-dimensional setter is required since it is tilted in two directions).

Furthermore, as another example, as shown in FIG. Otherwise, distance and slope can be measured simultaneously in the same manner as described above.

However, in this case, the distance a is from the reference reflecting surface (river) to the reflecting mirror (M), and from this mirror (M) to the lens (L).
) is the sum of the distances of 1 distance.

As described above, according to the present invention, the parallelism between the reference reflecting surface (R, I) and the surface to be measured (R2) and the distance therebetween can be simultaneously and accurately measured.

Therefore, an IC chip having a reflective surface of a minute area as a surface to be measured is mounted on a chip stand made of ceramic or the like.
In the case of J-keying, sufficiently high accuracy can be obtained by using the apparatus of the present invention. Moreover, the measurement can be performed without contacting the surface to be measured, and the apparatus itself can be configured extremely compactly.

In the semiconductor manufacturing process, the object to be measured is often of a small area, and six other inspection devices, a microscopic environment for alignment,
Since there are large size restrictions due to the transport mechanism, fixing mechanism, etc., control and measurement using the device of the present invention has extremely large advantages4.

[Brief explanation of the drawing]

FIG. 1 is a configuration explanatory diagram showing one embodiment of the present invention, FIG. 2 is an enlarged schematic diagram of the reflective surface (RIXI" (2) part, and FIG. 3 is a diagram showing another embodiment of the present invention. (Sl) (S2) Light source (n, +) (R2) Reflective surface (M) Half mirror (L) Lens (1) Two-dimensional position sezza (2) Beat splitter for division (3) 1-Dimensional Position Sen''J Procedural Amendment; (Voluntary) April 1980 l Japan Patent Office Commissioner Kazuinu Wakasugi 1. Indication of the Case 1985 Patent Application No. 28577 2. Name of the Invention Distance and Inclination Angle Measuring device 3, relationship with the case of the person making the amendment Patent applicant 5, date of amendment order Voluntary 6, number of inventions increased by amendment None 73-

Claims (1)

[Claims] (1) A light source that irradiates a beam onto the reference surface and the surface to be measured, a lens that focuses the beam reflected from the surface to be measured, an optical system that obtains split beams in two directions, and one of the split beams. The distance between the reference surface and the surface to be measured is measured by detecting the deviation of the image formation position between the reflected beam from the surface to be measured and the reflected beam from the reference surface. It is characterized by comprising a beam detection means and a second beam detection means located at the focal position of the other optical axis of the split beam and detecting the inclination angle formed between the surface to be measured and the reference surface. Distance and slope measuring device