JPS62286241A - Inspection of semiconductor device - Google Patents

Abstract

PURPOSE:To remove only abnormal semiconductor devices accurately, by measuring constant current and voltage values in the forward direction at junctions through external lead wires, computing the difference between the individual measured value and the average value of the measured values in the population of the same manufacturing lot, comparing the computed value with a standard value, thereby judging the quality. CONSTITUTION:A semiconductor element is bonded to a substrate supporting body. Each electrode of the semiconductor element is connected to an external lead wire with a thin metal wire. The constant current and voltage values in the forward direction at a junction are measured through the external lead wire. Based on the difference between the individual measured value and the average value of the measured values of the population of the same manufacturing lot, the defective individual measured values are detected. The distribution of the forward voltage (VBE) for every manufacturing lot is estimated by the measurements of a small amount of samples. The average value of the VBE of said manufacturing lot is obtained. A standard value is provided with respect to the average value. Then the dispersion in VBE among the manufacturing lots can be offset. The abnormal dispersion, which is yielded in the manufacturing processes can be detected accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION 3. Detailed Description of the Invention Field of Industrial Application The present invention relates to a method for electrically detecting the connection state between an electrode of a semiconductor element and each external electrode.

Conventional technology This type of inspection conventionally focuses on the fact that the junction forward voltage of a semiconductor element has a stable and constant value, and examines the coupling between the polar region of the semiconductor element and the metal electrode, and the external lead wire and the metal 'S line. A common method is to set standards by taking advantage of the fact that variations in parts, thickness and changes in thin metal wires are added to the forward voltage unique to semiconductor elements, and to inspect the coupling state of external lead-out wires on the element. It is carried out according to Particularly in the case of semiconductor devices that handle large currents, if the coupling is incomplete in some areas or the thickness of the thin metal wires is different, high resistance will exist in some parts of the circuit in the semiconductor device. Particularly strict standards are set and inspections are carried out to avoid excessive heat generation and fatigue, which can lead to fatal disconnections in semiconductor devices and cause market troubles for electronic equipment incorporating such semiconductor devices.

Problems to be Solved by the Invention These conventional methods have problems such as the contact between the polar region of the semiconductor element and the metal electrode, the connection area and strength between the electrode and the thin metal wire, variations in the shape of the thin metal wire, and furthermore, In addition to the variations between production lots, such as the connection area and strength of thin metal wires, there are also significant variations, and if inspection standards are made too strict, the production yield will be adversely affected, while if they are made too lax, quality cannot be ensured. It is causing inconvenience.

The present invention aims to eliminate such inconveniences by grasping the overall variation within a production lot and accurately removing only abnormal semiconductor devices whose characteristic values deviate from the distribution of the production lot. It's about how you can do it.

Means for Solving the Problems The present invention provides a method for bonding a semiconductor element to a substrate support, connecting each electrode of the semiconductor element and an external lead wire with a thin metal wire, and then determining the forward direction of bonding through the external lead wire. The semiconductor device is tested by measuring current and voltage values and detecting defects in the measured values on each side based on the difference between individual measured values and the average measured value of a population within the same manufacturing lot. For example, the emitter of a transistor.

When an electrode is formed by aluminum vapor deposition on the base region, the thickness of the aluminum vapor deposition film may vary slightly, and when bonding the emitter, base electrode, and thin metal wire, the bonding area determined by the dimensions of the bonding wedge may vary slightly. In addition, the shape of the bonding portion of the thin metal wire is different. Such slight variations indicate a larger resistance value as the current becomes larger, and even if a constant forward current is passed between the emitter and base electrodes under the same conditions, there will be a large difference in the forward voltage (VBE). If a certain VIE standard is established in order to appear, the standard must be set to a certain extent.

Therefore, VB [! By estimating the distribution of VBH by measuring a small amount of samples, finding the average value of vBE for that manufacturing lot, and setting a standard value for the average value, variations in VBH between manufacturing lots can be eliminated, and the manufacturing process can be The abnormal variation that occurred was extremely precise.

This allows for accurate detection.

In order to make it easier to understand the inspection method of the present invention, the drawings show a semiconductor device of the embodiment at a constant current (Ig=7A>) using a high-power transistor.

Emitter voltage VB[! FIG.

In an inspection example according to the present invention, several (10
~60), data processing is performed on the distribution and average values AA, AB, AC of the lot, and the standard width (ad) (in this example, ad=o, 0) is calculated for the average value.
The deviation of the average value for setting the standard values BA, BB, BC with 4V) is a process difference, and this is acceptable within the tolerance limit, but it is unacceptable if the individual measured value exceeds the standard value for each lot. It can be judged to be a good product. As a result, products with manufacturing defects are
definitely removed.

Effects of the Invention As described above, the present invention clearly distinguishes between manufacturing lot-to-manufacturing abnormalities and manufacturing abnormalities during the manufacturing process, making it possible to perform extremely accurate inspections. It is possible to rigorously inspect the connection state of electrodes and external lead wires, making it possible to significantly improve the reliability of the ever-increasing number of electronic devices.

[Brief explanation of the drawing]

The illustration represents the semiconductor device testing method of the present invention by the distribution of VBE characteristic measurement values.

Claims (1)

[Claims] After adhering the semiconductor element to the substrate support and connecting each electrode of the semiconductor element and an external lead wire with a thin metal wire, the junction forward direction constant current voltage value is measured through the external lead wire, and the individual measured values and A semiconductor device inspection method that calculates the difference between the measured value and the average value of a population within the same manufacturing lot, and determines the quality of the semiconductor device by comparing the calculated value with a preset standard value.