CS197553B1 - Method of tracing the defect places in isolating layers of the samples of microelectronic parts - Google Patents

Description

The invention relates to a method for detecting fault points in the insulating layers of microelectronic components.

In many microelectronic components and circuits, an important functional layer is the insulating layer of oxide or nitride of the base material. It serves either as a dielectric of a capacitor, insulation of flat conductors and the like, or also as a surface protection against the penetration of atoms used for diffusion into semiconductors, that is in the function of a mask. In both cases it is necessary to achieve a continuous layer without failures, because even a small opening in the layer prevents the functional use of its insulating properties. Therefore, various methods are used to identify fault points before the product is finished, in order to avoid potential ineffective operations on the defective surface. Optical observations in microscope, kinematic liquid crystal and electronic methods are used, such as scanning microscopy, transmission electron microscopy, scanning of surface replicas and their observation by microscope, electron diffraction and the like. These are slow methods and are not reliable at the μτη size.

The above drawbacks are overcome by the method of detecting fault points in the insulating layers of microelectronic component samples by providing the insulating layer sample with a protective layer and outlet on the inactive side and immersing it in an electrolytic bath with surface tension additive per sample. a metal or radical, such as cesium, is electroplated, and after the electroplating is complete, the sample is removed and the electrolyte residue is removed. It is an object of the invention that, in order to locate the location and distribution of the fault points on the sample, the places where the metal or radical is deposited are indicated.

It is furthermore advantageous according to the invention if during the electroplating application the magnitude of the passing galvanizing current is evaluated at a known voltage.

The method for detecting these disorders according to the invention solves the problem by allowing rapid and locally defined localization of the apertures and its resolution is not limited by optical aspects.

Prior to the actual indication of the fault points, it is preferable that the sample surface is briefly cleaned in a diluted atmosphere of an inert gas, such as argon, with a high discharge of 25 to remove impurities clogged on the insulating layer during galvanic layer formation.

Furthermore, according to the invention, it is advantageous if, upon completion of the galvanic deposition, electrons emitted from the sample are indicated by applying high voltage under vacuum.

Here, the fact that the layer is on a conductive substrate, on silicon, germanium or a metal is used to identify the holes in the insulating layer. The openings extend into the conductive material so that, under certain conditions, a suitable metal or radical can be applied to the openings in the galvanic bath. For example, if galvanic cesium is used, this material will form a deposit on the exposed areas of the pad, if it is a cathode.

The invention is explained in more detail by way of example and with reference to the accompanying drawing, in which a device for carrying out the method according to the invention is schematically illustrated.

In vessel 1, an electrolyte 2 is suitable. The electrode 3 as an anode is a source of cesium ions. The sample 4 with the insulating layer 5 under investigation is provided with an outlet 6 and forms a cathode. As the current passes through the holes 7, the respective element is deposited from the electrolyte bath 2 to form a conductive layer 8. The sample 4 is provided with a protective layer 9 on the inactive surfaces. To facilitate the access of the electrolyte 2 to the openings in the insulating layer 5 reducing the surface tension of the liquid and increasing the wettability. Also contemplated is the use of an ultrasonic transducer 10 to assist in the ingress of liquid and the elimination of gas bubbles. After application of the conductive layer 8, the sample is removed and washed away from traces of electrolyte 2.

The detection of holes is then carried out in several ways, such as

Claims (4)

SUBJECT Method for detecting fault points in insulating layers of samples of microelectronic components, which comprises coating the sample with insulating layer with a protective layer and an outlet on the inactive side and immersing it in an electrolytic bath with an additive for reducing surface tension, electroplating onto the sample the metal or radical, for example cesium, and after the electrodeposition is complete, the sample is removed and the electrolyte residue is removed, characterized in that the locations where the metal or radical is deposited are indicated to locate and distribute the fault points on the sample. 5 3 chemically. The very existence of water spots in the insulation results in the magnitude of the current passing through the electrolyte, so that the micro-ammeter included in the current circuit indicates a deviation proportional to the total area of the defective spots. The position and distribution of the defective spots can again be determined electrochemically, for example by applying an indicating foil composed of a metal foil and a porous paper layer saturated with an indicating dye. The color of the indicator dye will change at the current passage points to show the number and extent of the defective spots. Defective spots can also be detected on the basis of their vacuum emission properties, either by the lit luminophores on the screen where the electrons emitted, for example, by UV radiation, are focused and accelerated by a suitable voltage, or by the glow discharge light that will occur failures in application of ignition voltage in a gross vacuum of 1 to 10 kPa. For the electrochemical indication, it is suitable if, during the previous electrolytic process, layers of elements or radicals selectively react with the indicator dye used are formed in the openings. For emission indication we use again elements with low output work, eg Cs, Rb etc. The method according to the invention allows the indication and determination of the exact position of the fault point below 0.1 μΐη. YNÁLEZU 2. Method according to claim 1, characterized in that, during the electrodeposition, the magnitude of the electroplating current passing through is known at a known voltage. 3. A method according to claim 1 or 2, characterized in that, after the electroplating layer has been formed, thin layers and impurities of the deposited metal or radical are removed by bombarding the sample surface with inert gas ions in a diluted atmosphere. 4. A method according to claim 1 or 2, characterized in that, upon completion of the electrodeposition, electrons emitted from the sample are indicated by the application of a high voltage under vacuum.