JPS61125038A - Semiconductor wafer measuring mounting base - Google Patents

Abstract

PURPOSE:To give a function detecting whether there is any semiconductor wafer or not by providing a small hole connecting a pressure sensor with a part of a channel different from a position provided with a suction hole besides a suction hole for plural channels suck-fixing a semiconductor wafer to be measured. CONSTITUTION:A suction hole 3 is connected with a small hole 6 through a channel 5 in order to detect whether there is any semiconductor wafer or not. The lower part of this small hole 6 is connected with a pressure sensor 8 through a connecting tube 7. When the semiconductor wafer is not mounted on a surface of the hole 6 as the small hole 6 connected with the pressure sensor 8 is provided separating from the suction hole 3, a pressure is almost an ambient pressure without any connection with a suction motion of the suction hole 3. When the semiconductor wafer is mounted, as a result that the upper part of each channel is closed by the lower surface of the semiconductor wafer, a low pressure is obtained according to the suction motion made from the suction hole 3 as the channel is sealed. Therefore, a pressure sent to the pressure sensor 8 is changed into a binary pressure according to whether the semiconductor wafer is mounted or not.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a semiconductor wafer measurement stage.
For example, it relates to a technique that is effective when used in a fully automatic semiconductor wafer prober.

[Background technology]

In semiconductor wafer blowbars, which are responsible for the final checking process of semiconductor wafers, as the diameter of semiconductor wafers becomes larger, manual work using tweezers, throats, or other tools becomes difficult, so there is a shift to so-called tweezers-less, or in other words, , Automatic loading and unloading of semiconductor wafers is published in the November 1978 issue of R Electronic Materials J, pages 139 to 1.
43.

That is, a plurality of (for example, 25) semiconductor wafers are sequentially transferred one by one from a storage container (cassette) to a loading position (coarse alignment stage) by a nine-belt conveyor. Then, this semiconductor wafer is transferred to a suction table (semiconductor wafer measurement mounting table) of a blobbing machine using a Bernoulli chuck or the like. Next, the semiconductor wafer that has been measured is transported from the suction table to an unloading position by blowing air pressure or the like, and placed in a storage container by a round belt conveyor.

As described above, the semiconductor wafer is carried into the blowing machine in a completely non-contact state with respect to the semiconductor wafer surface, and the tM
The appearance is made.

However, with the above-mentioned fully automatic semiconductor wafer prober, the unloading operation of the semiconductor wafer from the above-mentioned suction table to the unloading position may not be carried out due to insufficient compressed air pressure, or the measurement may be restarted after the measurement is interrupted due to a power outage, etc. At startup,
There is a possibility that the next semiconductor wafer to be measured may be carried in even though the semiconductor wafer is still placed on the suction table. If the semiconductor wafers are overlapped in this way, damage will occur to the surface of the underlying semiconductor wafer. Alternatively, if a sensor is installed at the unloading position to detect the semiconductor wafer and the next semiconductor wafer is transferred, the fully automatic semiconductor wafer prober cannot detect the semiconductor wafer because the detection output of the semiconductor wafer cannot be obtained. As a result of continuing to wait, you end up wasting your time.

Therefore, the inventor of the present application considered detecting whether or not a semiconductor wafer is placed on the semiconductor wafer measurement mounting table. That is, as shown in FIG. 4, a pressure sensor P is provided in the middle of a suction hole connected to a plurality of grooves provided on the surface of the semiconductor wafer measurement mounting table or a tube connecting the suction hole and the vacuum pump. The presence or absence of a semiconductor wafer is detected from the change in pressure. That is, if a semiconductor wafer is present, the pressure in the suction hole will decrease due to its vacuum suction, and if there is no semiconductor wafer, the pressure will increase. In this case, a valve (2) is provided to selectively carry out the suction and fixation, and when the valve (V) is open, the pressure changes to have two values depending on the presence or absence of the semiconductor wafer. However, the pressure varies slightly depending on the size of the semiconductor wafer to be measured because the number of grooves to be closed differs, and even when there is no semiconductor wafer, air resistance passing through the relatively small hole causes the pressure inside the suction hole to increase. The pressure is made less than atmospheric pressure. Further, when the valve V is closed, the inside of the suction hole becomes atmospheric pressure. For this reason, in the above method, the pressure sensor forms a multivalued detection output, making it difficult to obtain a highly accurate detection output of the presence or absence of a semiconductor wafer.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor wafer measurement mounting table that has a simple configuration and a highly accurate detection function for the presence or absence of a semiconductor wafer.

The above and other objects and novel features of this invention include:
It will become clear from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows.

That is, in addition to the suction holes for the plurality of grooves for sucking and fixing the semiconductor wafer to be measured, a small hole is provided to connect the pressure sensor to a part of the grooves different from the position where the suction holes are provided.

〔Example〕

FIG. 1 shows a schematic cross-sectional view of one embodiment of the invention.

The semiconductor wafer measurement mounting table according to this embodiment is used as a suction table in the fully automatic semiconductor wafer prober, although it is not particularly limited.

That is, although not shown, a fully automatic semiconductor wafer processor is generally comprised of a blobbing machine section and a semiconductor wafer transfer section.

As is well known, the blow pink machine section is fixed by moving a suction table that suctions and fixes a semiconductor wafer placed on its upper surface in the X and Y directions using an X and Y stage and rotating it in the θ direction. The device consists of a probe board, etc., and the tips are aligned with the bonding pads of the wafer chip with respect to the probes arranged corresponding to the measurement locations. For this positioning, aligning is performed, and the X-axis of the chip arrangement on the semiconductor wafer and the X-axis of the above-mentioned
This is achieved by adjusting the θ direction. After this,
The tip of the probe is aligned with the bonding pad of the first wafer chip to be measured. Thereafter, by continuously moving the probe in the X direction or the Y direction at intervals of one chip at a time, the probe is automatically aligned with respect to the bonding pads of other wafer chips. These X, Y
Movement of the stage and rotation control in the θ direction are performed with high precision using a pulse motor.

Further, the suction table is moved in two directions (up and down) using air or a pulse motor. In other words, the positioning operation by controlling the X and Y stages is performed with the suction table lowered, and during measurement, the suction table is raised and the required contact pressure is applied between the probe and the bonding pad of the wafer chip. It is something that connects.

A transfer arm is attached to the blowing machine section. This transfer arm uses, for example, a Bernoulli chuck that suctions below the surface of the semiconductor wafer without contact, and conveys the semiconductor wafer transferred to the load position onto the suction table at the load position.

Further, after the measurement of the semiconductor wafer has been completed, after the suction table moves to the unload position, air or the like is blown out from a diagonal small hole toward the unload position, and the semiconductor wafer is transported to the unload position.

A semiconductor wafer transfer section is provided for such a blobbing machine section equipped with an automatic semiconductor wafer loading/unloading mechanism. The semiconductor wafer transfer unit has a circular elevator mechanism that connects a plurality of elevator mechanisms in which storage containers (cassettes) each containing semiconductor wafers are installed, and a loading position and an unloading position that also function as a coarse alignment stage. It consists of a belt conveyor. Such a fully automatic semiconductor wafer prober is described in detail in, for example, Japanese Patent Publication No. 59-2182.

In FIG. 1, one component block 2 forming the measuring surface of a measuring stage 1 for semiconductor wafers is shown. In the same figure, the small hole provided vertically in the center is
A suction hole 3 is configured. That is, its lower part is connected to a vacuum pump via a tube (not shown).

As shown in the plan view of FIG. 2, a plurality of concentric holes 94a to 4d are provided on the surface of the component block 2. These concentric grooves 4a to 4d are connected in common by two V-shaped grooves 5a and 5b that run radially around the suction hole 3, although this is not particularly limited.

Furthermore, a plurality of diagonally directed injection holes 9 are provided on the surface of the component block 2. These injection holes 9 are
They are commonly connected by a cavity 9a of a recess provided on the lower surface side of the component block 2.

Although not shown, compressed air (or nitrogen gas) is selectively supplied to this cavity 9a through the pulp, and is ejected from the injection hole 9 in the diagonal direction shown by the arrow. This causes the semiconductor wafer to be carried out to the unload position as described above. In addition, in Figure 2,
The small injection hole 9 is omitted.

In this embodiment, in order to detect the presence or absence of a semiconductor wafer,
The suction hole 3 is connected to a small hole 6 via a groove 5. This small hole 6 is connected to a pressure sensor 8 via a connecting tube 7 at its lower part. This pressure sensor 8 is
Although not limited to this, a 'KP 100AJ monolithic pressure sensor sold by Philips of the Netherlands may be used.

Note that other component blocks are combined on the lower side of the component block 2, and the semiconductor wafer measurement stage 1 is assembled as a whole.
Configure.

In this embodiment, the small hole 6 connected to the pressure sensor 8 is provided separately from the suction hole 3, so if no semiconductor wafer is placed on the surface of the small hole 6, the suction of the suction hole 3 is Regardless of the operation, the pressure is set to 10000 psi. on the other hand,
When a semiconductor wafer is placed, the upper part of the groove is closed by the lower surface of the semiconductor wafer, and as a result, the groove is sealed and a low pressure is applied according to the suction operation performed from the suction hole 3. In this way, the pressure transmitted to the pressure sensor 8 can be a binary pressure depending on whether a semiconductor wafer is placed or not. Also,
By arranging the small hole 6 leading to the pressure sensor 8 in the center, a relatively low pressure can be applied to even the smallest diameter semiconductor wafer.

FIG. 3 shows a circuit diagram of one embodiment of a detection circuit for forming a detection signal for the presence or absence of a semiconductor wafer. In the figure, the Brifuji circuit indicated by resistors R1 to R4 is an equivalent circuit of the monolithic pressure sensor. The output of the pressure sensor 8 shown in the Brifuji circuit is the operational amplifier circuit OP.
1 and resistors R5 and R6 for setting the gain thereof. In order to perform temperature compensation or atmospheric pressure compensation in the amplified output of this amplifier circuit, in this embodiment, a dummy pressure sensor 8' and an amplifier circuit similar to the above (OF2, R5, R6) is provided. The dummy pressure sensor 8' is placed in the atmosphere.

The amplified outputs of the pair of pressure sensors 8 and 8° are differentially supplied to the inverting input (-) and non-inverting input (+) of the operational amplifier circuit OP3. Due to the differential amplification effect of the operational amplifier circuit OP3, it is possible to compensate for fluctuations in atmospheric pressure or the temperature of the amplifier circuit.

That is, when no semiconductor wafer is placed, the repressure sensor 8.8' sends out an output signal according to the same atmospheric pressure, so that variations therein can be compensated for. Also,
Temperature dependence, power supply voltage dependence, etc. in the amplifier circuits OPI and OF2 are also canceled out. As a result, if no semiconductor wafer is placed, a low-level output signal similar to the ground potential of the SO' circuit is obtained from the output of the operational amplifier circuit OP3. This turns transistor Q1 off. In addition, if a semiconductor wafer is placed, the difference in the amplified signal of the output signal obtained from the repressure sensor 8.8° is transmitted to the operational amplifier circuit OP3 and its resistors R7 and R.
It is set to a high level according to the gain set by 8. Although not particularly limited, this high level is transmitted to the base of the transistor Q1 via the resistor R9 and the diode D1, turning on the transistor Q1.

Depending on the on/off state of the transistor Q1, a low level/high level detection output is obtained from its output. The emitter of the transistor Q1 is coupled to the ground potential of the circuit, and the collector is provided with a resistor R11 as a load and a light emitting diode LED. This light emitting diode LED is used to display the presence or absence of a semiconductor wafer.

Note that, although not particularly limited, the resistor R9, the diode D1, and the base-to-emitter resistor R of the transistor Q1
By providing the IO, the operational amplifier circuit OP
Even if the low level output signal of No. 3 is at an intermediate level higher than the ground potential of the circuit, the transistor Q1 is prevented from being turned on. That is, transistor Q
1 connects the output voltage of the operational amplifier circuit OP3 to resistors R9 and R1.
The voltage divided by 0 is applied to diode D1 and transistor Q.
1 will not be turned on unless the voltage required to turn both on is reached.

〔effect〕

(1) By providing a small hole connected to a suction hole through a groove provided on the measurement surface of a semiconductor wafer and connecting a pressure sensor to this, the Can create pressure changes. This provides the effect of realizing highly accurate detection of the presence or absence of a semiconductor wafer.

(2) According to (1) above, since the beam detects binary pressure changes, it is possible to detect the presence or absence of a semiconductor wafer with high accuracy even using an inexpensive pressure sensor with relatively low sensitivity. Effects can be obtained.

(3) By providing a dummy pressure sensor placed in the atmosphere as a detection circuit and forming a difference signal,
Temperature compensation, power supply voltage dependence, etc. can be compensated for in an amplifier circuit that amplifies atmospheric pressure fluctuations and minute sensor outputs. Therefore, due to the synergistic effect with the above (1) or 2), it is possible to achieve the effect that the presence or absence of a semiconductor wafer can be detected extremely stably and with high accuracy.

(4) If the above (1) or 3) is applied to a fully automatic semiconductor wafer prober, the presence or absence of a semiconductor wafer can be reliably detected. The effect is that damage and wasteful waiting time can be prevented.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that this invention is not limited to the above Examples and can be modified in various ways without departing from the gist thereof. Nor. For example, any pressure sensor may be used as long as it can detect changes in atmospheric pressure as described above. Furthermore, the means for connecting the suction hole and the small hole to the vacuum pump and the pressure sensor, respectively, can take various embodiments. Furthermore, the detection circuit that processes the output of the pressure sensor is
Numerous embodiments can be adopted, such as a configuration in which the dummy pressure sensor is omitted.

[Application field]

The present invention can be widely used in various semiconductor wafer inspection devices that suction and fix a semiconductor wafer and measure the same, such as a fully automatic semiconductor wafer prober.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention, FIG. 2 is a schematic plan view thereof, FIG. 3 is a circuit diagram showing an embodiment of the detection circuit, and FIG. FIG. 2 is a principle diagram showing a method for detecting the presence or absence of a semiconductor wafer that was studied prior to the invention.

Claims (1)

[Claims] 1. A plurality of grooves for sucking and fixing a semiconductor wafer to be measured, a suction hole coupled to the groove, a part of the groove different from the position where the suction hole is provided, and a pressure sensor. A semiconductor wafer measurement mounting table comprising a small hole for coupling and a semiconductor wafer detection circuit including the pressure sensor. 2. Claim 1, wherein the semiconductor wafer detection circuit includes a differential amplifier circuit that receives the output of the pressure sensor and the output of a similar pressure sensor placed in the atmosphere. Semiconductor wafer measurement mounting stand described in Section 1. 3. The semiconductor wafer measurement stage according to claim 1 or 2, wherein the semiconductor wafer measurement stage is installed in a fully automatic semiconductor wafer prober.