JPS5867088A - Light probe head - Google Patents

Abstract

PURPOSE:To maintain at constant value the clearance between the light emitting part and the light receiving plane of an element to be tested and improve the reproducibility of the test, by projecting the fringe part of the optical fiber end part from the central part, and providing an abrasion resistant member on the fringe part. CONSTITUTION:An outer coating material 9 is formed around the optical fiber with a clad part 8, and a metallic sheath material 11 is constituted outside. The end part 11' of said metallic sheath material 11 has a conical aperture part, and on the top end a thin disc 13 which has a through hole 12 at the center and is constituted of Al2O3 crystal such as sapphire or of a material excellent in abrasion resistance such as a super steel alloy is fixed in a structure of slight projection from the top end part of the sheath material 11 by fitting or adhesion. The part contacted on the surface of the light emitting element to be tested is constituted of a material high in abrasion resistance, and the abrasion of the contacted part is not generated against repeated probings resulting in the prevention of damages of the light receiving part of an optical fiber. Since the clearance between the light receiving part and the contacted part is constantly maintained, the improvement of the reproducibility of the light receiving characteristic during probing can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical probe head for detecting the light emission output of an optical integrated circuit (hereinafter referred to as an optical IC) using a light emitting diode, a semiconductor laser, or the like.

In normal testing of semiconductor integrated circuits (IC, LSI) in the wafer state, electrical signals are exchanged between the test equipment and the semiconductor integrated circuit under test using a probe using a thin metal wire made of highly wear-resistant tungsten steel or the like. head is used.

- In testing ICs and the like, the ability to efficiently send and receive optical signals as well as electrical signals is an important condition for the probe head of the testing machine.

becomes.

The probe head for testing optical ICs is composed of a so-called fiberglass light guide that receives the light emitted from the optical IC to be tested with high efficiency and introduces it into the main body of the testing machine. The optical function of the light receiving surface,
It is necessary to have a structure that will not be damaged over a long period of time.

That is, conventionally, the structure of the junction between the light emitting element and the optical fiber that conveys the emitted light of a laser diode such as an optical IC or a light emitting diode is as shown in FIG.゛There was something.

FIG. 1(m) shows a configuration in which an optical fiber 2 whose light-receiving surface 1 is finished as a mirror without diffused reflection is bonded and fixed to a radiation surface 4 of a light-emitting element 3 with a resin 6. 1) shows a configuration in which an optical fiber 2 having a light-receiving surface 1 having a lens structure 6 is installed near a radiation surface 4 of a light-emitting element 3.

As mentioned above, FIGS. 1(M) and 1(B) show the connection configuration of a light emitting diode and an optical fiber, but the light emitting output 1 luminous efficiency of the light emitting element, etc. can be determined based on the state of the wafer or chip.
In the case of an inspection device that inspects with S., it is necessary to introduce the light emitted from the microscopic area into the main body of the photodetector with little loss.
The light receiving surface of the optical probe head must always maintain a smooth surface without diffused reflection.

However, the optical probe head is repeatedly placed in pressure contact with the surface of the light-emitting element, which is the device to be tested, or placed in close proximity with an interval of several micrometers.
This may cause damage to the optical fiber head and impair its function as an optical fiber head.

As mentioned above, when measuring the luminous efficiency of a light emitting element using an optical probe head, it is necessary to increase the abrasion resistance and damage resistance of the tip of the head due to its nature. As mentioned above, bringing the core part 7 and cladding part 8 of the optical fiber 2 into direct contact with the light emitting part 4 of the device under test 3 as shown in FIG. This is not desirable as it may cause damage. Therefore, as shown in Fig. 3, the core 7 and cladding 8 are made a little shorter than the outer covering part 9 and reinforcing sheath part 1o of the optical fiber 2, so that the light-receiving surface 1 of the optical fiber 2 body can be kept in contact with the device under test by several micrometers. This can prevent damage to one part of the light-receiving surface, but as is well known, the test probe head repeatedly presses against the device to be tested many times due to its function, so the outer sheath 9 and sheath used in optical fibers are damaged. Resin material which is material 1o (
(silicone resin, urethane resin, etc.) are easily worn out and damage the light receiving surface of the optical fiber 2.

In addition, in order to prevent coupling loss from decreasing in the optical probe head, the gap between the optical fiber tip and the light emitting element is kept constant even when using an optical fiber with the tip lens structure shown in Figure 1 (B). Therefore, as shown in FIG. 4, it is necessary to maintain the gap using a sheath material 10 or the like, but this causes the above-mentioned problems.

An object of the present invention is to prevent damage and wear to the tip of the conventional optical probe head.

Embodiments of the present invention will be described below based on the drawings.

FIG. 6 shows a front sectional view of an optical probe '6 head in one embodiment of the present invention, and FIG. 6 shows a bottom view of FIG. 5. Note that the same numbers are given to the same parts as in the conventional example. As shown in these figures, the outer diameter of the cladding part 8 is 10
A sheathing material 9 is formed on the optical fiber having a thickness of 0 to 150 μm, and a metallic sheathing material 11 is further formed on the outside thereof. The end portion 11' of the metal sheath material 11 has a conical opening, and the tip portion is made of a 120s crystal such as sapphire or a wear-resistant material such as super steel alloy with a through hole 12 in the center. By fitting or gluing the thin circular pig 13 made of a material with excellent properties,
The sheath material 11 is fixed in a structure that protrudes slightly from the tip.

In the optical probe head of the example, as described above, the part that contacts the surface of the light emitting element to be inspected is made of a material with high wear resistance, and even with repeated blobbing, the contact part does not wear out. This prevents damage to the light receiving section of the optical fiber. In addition, since the gap between the light receiving part and the contact part is always kept constant, it is possible to improve the reproducibility of the light receiving characteristics during blowing.
- Shows examples. Although the light-receiving part of the optical fiber is shown in the case of a planar shape in FIG.
The same effect can be easily obtained even in the case of a tip lens coupling structure having a (low loss) shape by using a structure as shown in FIG.

Note that the thin disc 13 at the contact part has a fitting or adhesive structure, so if this part is damaged, simply replacing the thin disc 13 will keep the optical probe body functioning semi-permanently. It is possible.

FIGS. 8 and 9 show an optical probe head according to still another embodiment of the present invention, which has a structure in which the coupling loss between the light emitting element 3 and the optical probe head 2 is reduced. As a coupling configuration for reducing coupling loss, there is a method of using a ball lens between the light emitting element and the optical fiber, but in this embodiment, as shown in FIGS. A structure in which a thin layer 14 for holding a ball lens is formed, a concentric hole is formed in the thin layer 14, and a ball lens 15 is held in the hole. This is an optical probe head. In this optical processor 6-head, the surface of the condensing ball lens 16 is held by one main surface of a highly wear-resistant thin disk 13, so that it cannot come into contact with the surface of the light emitting element to be inspected. Because there is no lens, it can maintain its function as a condensing lens for a long time.

As explained above, by using the optical probe head of the present invention, the light-receiving surface of the optical probe can be polished while inspecting the optical output of light I(j) or light emitting diode in wafer state and chip state. Protected by a thin sun disc that is highly abrasive,
Since the light-receiving surface is not damaged and the gap between the light-emitting part of the device to be inspected and the light-receiving surface can always be kept constant, it is possible to significantly improve the reproducibility of inspection.

[Brief explanation of drawings]

Figures 1 (M) and (B) are diagrams showing the connection configuration of a general light emitting diode and an optical fiber, and Figures 2, 3, and 10 are cross-sectional views showing a conventional light emitting diode connection, respectively. 5 is a sectional view of an optical probe head in one embodiment of the present invention, FIG. 6 is a bottom view of the same optical probe head, and FIG. 7 is a sectional view of an optical probe head in another embodiment of the present invention. FIG. 8 is a cross-sectional view of an optical probe head in still another embodiment of the present invention, and FIG. 9 is a cross-sectional view showing the structure of the probe tip of FIG. 8. 1... Light-receiving surface of optical fiber, 2...
Optical fiber, 3... Light emitting element to be inspected, 4.
...Light emission surface, 9 ... Outer covering of optical fiber, 10 ... Sheath material, 11 ... Metal sheath %13 ... Thin circle Board, 15...
ball lens. Name of agent: Patent attorney Toshio Nakao and one other Jl
i1 figure 21! ! 13 Figure 14 Figure 5 Figure 16 Figure 17 Figure 8 Figure 9

Claims (1)

[Claims] An optical probe head characterized in that a peripheral edge of one end of an optical fiber projects beyond the center of the optical fiber, and a wear-resistant member is provided on the peripheral edge.