JPH0348529Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an IS FET (ion sensitive FET) testing device, and more specifically relates to simplification of the testing process.

<Prior Art> As a conventional IS FET measurement system, the configuration shown in FIG. 4 is known. In the figure, 1 is an electrolytic solution filled in a container 2. A comparison electrode 3 and an IS FET 4 as a measuring electrode are inserted into this container 2, and the potential difference from each electrode is transmitted via a lead wire 6. Measured with a total of 5 (FET drive circuit is omitted in the diagram).

As shown in FIG. 5, the IS FET 4 has a drain 13, a source 13', a gate part 15, and an electrode 45 for connecting lead wires, which are made of an n ⁺ layer as liquid contact parts, on the surface of a silicon wafer 6. This electrode portion is potted with an insulator.

In the conventional example described above, the IS FET to be inspected is manufactured through the steps shown in FIGS. 6a to 6d. That is,
In step a, multiple IS FETs each consisting of a drain, source, gate and electrode are formed on a silicon wafer, in step b they are separated one by one, in step c lead wires are connected to the electrodes, and in step d the electrodes are separated. The parts are potted with insulating material.

<Problems to be solved by the invention> However, with the conventional inspection equipment described above, even if there is a defect during the diffusion process when forming the drain or source, it is not possible to inspect it until the IS FET is completed up to the potting stage. Without it, the test cannot be performed. As a result, there is a disadvantage that the steps taken to complete the process are wasted. The present invention was developed in view of the above-mentioned drawbacks of the conventional technology, and the purpose of the present invention is to provide an inspection device that does not waste man-hours on defective products by inspecting the ion sensor before separating it from the silicon wafer. shall be.

<Means for solving the problems> The structure of the present invention to solve the above problems is as follows.
In an apparatus for testing the performance of the ion sensor using a potentiometer by immersing an ion sensor and a reference electrode in an electrolyte, the reference electrode has a hole at the bottom and an inlet and an outlet for the electrolyte; a container in which the ion sensors are to be immersed, a silicon wafer on which a plurality of ion sensors to be inspected are formed, and a hole in the container is located at a location where the ion sensors are to be in contact with the liquid;
The device is characterized by comprising means for sealing the electrolytic solution to prevent it from leaking to areas other than those to which it should come in contact with the electrolyte, and means for guiding the reference electrode and the electrodes of the ion sensor to a potentiometer.

<Embodiment> FIG. 1 is a perspective view showing an embodiment of the present invention. In the figure, reference numeral 1 denotes a container in which the comparison electrode 3 is immersed, and is placed on a silicon wafer 20 fixed on a support 15. The outer periphery of the upper part of the container 10 is wound around and held by an elastic band-shaped fixing fitting 11, and the ends of the fixing fittings are brought together and extended, and a hole (not shown) formed in the first support column 12 is inserted into the hole (not shown). It penetrates and is supported so as to be movable in the A direction. This first support 12 is the second support 1
3 so as to be rotatable in the direction of arrow A. 1
6 is an elastic body made of a coil spring, and one end is connected to the support base 1.
5, and the other end is fixed to a presser fitting 14 disposed above the fixing fitting through a seam of the fixing fitting.

According to the above configuration, the container 10 can be moved to any location on the silicon wafer, and the silicon wafer can be pressed with a predetermined pressure by the coil spring.

FIG. 2 is a plan view a of the container 10 and X-X of a.
A hole 30 is formed at the bottom of the container 10, and an O-ring slightly larger than the diameter of the hole 30 is installed to prevent the electrolyte from leaking between the hole and the silicon wafer 20. It is located.
Note that 32 is an inlet for the electrolytic solution, and 33 is an outlet for the electrolyte. In this example, the inlet is arranged close to the hole 30 to more accurately maintain the concentration of the electrolyte in contact with the IS FET. 34 is a prober that is placed outside the container 10 and takes out the output from the electrode of the IS FET, and the other end of this prober is connected to the lead wire 6.
connected to the potentiometer via.

IS FET characteristics are measured multiple times by changing the concentration of the electrolyte, but measurements are taken after an electrolyte of a predetermined concentration is allowed to flow in from the inlet for a certain period of time. Although not shown in the figure, the inlet and outlet ports are treated to prevent the electrolyte from falling onto the silicon wafer. Also, one
After the inspection of the IS FET is completed, the electrolyte in the container may be sucked up with a dropper, etc., and then moved to the next IS FET, or it may be moved to the side as it is.

Figure 3 shows IS formed on a silicon wafer.
This is an enlarged view of the positional relationship between the FET and the O-ring 30. The inner circumferential side of the O-ring is filled with an electrolytic solution, and an electric signal corresponding to the concentration is extracted from the prober 34. In this example, the electrolytic solution was sealed using an O-ring and the container was pressed using a coil spring, but the method is not limited to this example, and various sealing and pressing methods can be used.

<Effects of the invention> As explained above in detail with the embodiments, according to the invention, defective products can be checked on the silicon wafer in advance, so that IS FETs can be efficiently manufactured.
can be produced.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the construction of an embodiment of the ion sensor testing device of the present invention, Fig. 2 is a plan view a showing details of the container, and XX sectional view b of a, and Fig. 3 is a silicon wafer. Fig. 4 is a diagram showing a conventional measurement example, Fig. 5 is a detailed explanation of the IS FET, and Fig. 6 is an illustration of the IS FET. Diagram showing the production process. DESCRIPTION OF SYMBOLS 1... Electrolyte, 3... Reference electrode, 5... Potentiometer, 10... Container, 30... Hole, 11... Fixing fitting, 20... Silicon wafer, 31... O-ring, 34... Prober.

Claims (1)

[Scope of utility model registration request] In an apparatus for testing the performance of the ion sensor using a potentiometer by immersing an ion sensor and a reference electrode in an electrolyte, the reference electrode has a hole at the bottom and an inlet and an outlet for the electrolyte; a silicon wafer on which a plurality of ion sensors to be inspected are formed; a hole in the container is located at a location where the ion sensor is to be in contact with the liquid; An ion sensor testing device comprising: means for sealing to prevent leakage to other sources; and means for guiding the reference electrode and the electrode of the ion sensor to a potentiometer.