JPH01312480A - Integrated-circuit burn-in system - Google Patents

Abstract

PURPOSE:To perform excellent burn-in by controlling the variation of the base voltage of one transistor constituting the current switch part of an emitter coupled type logic circuit (ECL), and switching the current switch part of each ECL in an integrated circuit. CONSTITUTION:When burn-in is performed, at first a variable base power source VBB1 is set at a voltage value lower than a fixed base power source VBB2. Thus, a TR111 in each ECL becomes an OFF state and a TR112 becomes an ON state. Then, the burn-in started. When a specified time has elapsed after the start of the burn-in, the burn-in device changes the voltage of the variable base power source VBB1 to the voltage value higher than that of the fixed base power source VBB2. Then, the TR111 is changed from the OFF state to the ON state, and the TR112 is changed from the ON state to the OFF state. Then, the voltage value of the variable base power source VBB1 is alternately changed from the voltage value that is lower than that of the other fixed base power source VBB2 to the high voltage value. Thus, the TR111 and the TR112 alternately become the ON or OFF state. The same phenomena occur in a plurality of TR111a-TR111k.

Description

[Detailed Description of the Invention] [Summary] Regarding the burn-in method for integrated circuits that applies thermal stress to integrated circuits including ECLs through burn-in, it is easy to use without using various test patterns for switching the current switch sections of each ECL. Effectively test each ECL with suitable test equipment.
In the integrated circuit burn-in method, which applies thermal stress to an integrated circuit including multiple ECLs, one of the current switch parts of the ECL is switched to ensure good burn-in. Base power supply of transistor section V 1
The voltage value of lBH can be changed to a voltage value lower or higher than the voltage value of the fixed base power supply VBB2 of the other transistor section, and the voltage value of one variable base power supply VBBl can be changed periodically during burn-in to the voltage value of the fixed base power supply VBB2 of the other transistor section. Power supply VBB
2 by alternating voltage values lower and higher than E.
The current switching section of CL is configured to perform current switching.

[Industrial application field]

The present invention applies to a large number of emitter coupled logic circuits such as ECI-gate arrays.
The present invention relates to a burn-in method for integrated circuits, which applies thermal stress through burn-in to integrated circuits such as LSIs (hereinafter referred to as ECL).

・This prior art] Figure 4 shows the basic configuration of ECL.
0 to 214 are transistors (hereinafter TR210 to TR2
14 (not shown), 220 to 223 are resistors (hereinafter R22O-
R223). In addition, VCC is a common collector power supply, VE E I is an emitter power supply with constant current characteristics (hereinafter referred to as constant current power supply), ■-2 is an emitter power supply, ■
, 8 is the base power supply, Vo. 〉VRB>VRB2.

TR211 and TR212 are connected in parallel, and the emitters of these transistors and the emitter of TR213 are connected in parallel and connected to a constant current power supply VEEI, and together with R221 and R222 connected to their collector sides, constitute a current switch section. . Input A is supplied to the base of TR211, and human power B is supplied to TR212. TR2
A fixed base power supply VB11 is connected to the base of 13.

TR210 constitutes an emitter follower together with R220, and takes out the output from the common collector side of TR211 and TR212. Emitter side of TR210 (1)) R22
0 is connected to a fixed emitter power supply VEE2.

TR214 forms an emitter follower together with R223, and takes out the output from the collector side of TR213. TR2
R223 on the emitter side of 14 is the fixed emitter power supply V
Connected to Eε2.

In this configuration, human power A or human power B of the current switch section
When is on, TR211 or TR212 is on and current flows through R221 on its collector side, and when both human power A and human power B are off, TR211 and TR2
12 both turn from on to off, and TR213 on the opposite side turns from off to on, current flows through R222 on its collector side, and a current switch is performed.

Therefore, the NOR output of the input A of the TR 211 and the human power B of the TR 212 is taken out from the emitter output terminal of the TR 210 of the emitter follower section, and the OR output of the human power A or the human power B is taken out from the emitter output end of the TR 214.

When an integrated circuit such as an ECL array or LSI in which a large number of such ECTs are arranged is manufactured, it is necessary to stabilize its characteristics and eliminate initial defects before its actual use. An exam will be held. In this case, in order to shorten the test time, a burn-in test is performed in which the integrated circuit is tested in a high temperature environment and under energized conditions as an acceleration test that applies thermal stress to the integrated circuit.

In order to create a high-temperature environment for integrated circuits, a method is generally used in which the temperature around the integrated circuit is increased using a constant temperature device. In addition, by supplying a predetermined voltage to the integrated circuit, each component in the integrated circuit is made energized. For example, for ECL, a given V c c + V B !
11 V E I! By supplying I and VRB2, each ECL is energized.

By performing such burn-in tests, the characteristics of manufactured integrated circuits are stabilized in a short period of time, and initial defects are detected within this test period, so the incidence of defects after actual use is extremely low. This makes it possible to provide a highly reliable integrated circuit.

[Problem to be solved by the invention]

In a burn-in test of an integrated circuit including an ECL, the power supply voltage supplied to the integrated circuit is usually kept constant during burn-in.

In this case, in ECL, VCC, VBB, VE
When the power supply voltages such as EI and VEE
A current flows through either one of R213, and that state is maintained. Whether the flow goes to the set of TR211 and TR212 or to TR213 is determined by the circuit configuration, but in FIG. 4, the levels of human power A and B in the unmanned state are VE! When the level is 2, a current flows to the TR 213 side, and this state is maintained during the burn-in period.

Therefore, the transistor on the conductive side (TR21
3) can be burn-in, but the transistors on the other side (TR211, 21
2 etc.) cannot be burn-in sufficiently. For this reason, a problem arises in that the stabilization of characteristics and the detection of initial failures are only performed insufficiently on the side that is in a non-conducting state.

To solve this problem and to properly burn-in the transistors on the other side of the ECL, it is necessary to apply a test pattern to the data input terminal of the integrated circuit that operates the ECL so that the current switch section of the ECL switches. be. However, in the case of integrated circuits such as LSIs and VLSIs, the number of device elements including ECLs is extremely large, so the number of circuits and circuit operation modes become enormous. As a result, the number of test patterns becomes enormous, requiring a great deal of effort and time for testing, and the cost increases as pattern generation circuits and signal distribution circuits must be added to the burn-in equipment. was there.

The present invention has been improved so that it is possible to effectively switch the current switch section of the ECL using a simple test device and perform burn-in successfully without using various test patterns for switching the current switch section of the ECL. The purpose is to provide a burn-in method for integrated circuits.

[Means to solve the problem]

The means adopted by the present invention to solve the above-mentioned problems are as follows:
This will be explained with reference to FIG. FIG. 1 shows a principle diagram of the present invention.

In FIG. 1, 111 (111, to 11 L) and 112 are transistor parts that constitute the ECL (hereinafter referred to as TRI 11 (TRII 1.-TR111k)).
, indicated as TR112). In principle, only one TR111 is required, but as shown in the figure, a plurality of TR112-111. may be connected in parallel. The common emitters of TR111 and TR1'12 are connected to a constant current power supply V E E l .

The base of TR112 is a fixed base power supply VII with a fixed potential.
B2, and the collector is connected to the load resistor 122 (hereinafter R1
22) through the collector power supply V. Connected to C.

On the other hand, human power is applied to the base of TR111, and the collector is connected to the collector power supply V via a load resistor 121 (hereinafter referred to as R121). Connected to 0. An input is applied to the base, and a fixed base power supply V of TR1'12 is applied.
A variable base power supply V B B 1 that generates two types of voltages, a higher voltage and a lower voltage than BB2, is connected. A resistor 120 (hereinafter referred to as R120) is a variable base power supply VB.
, lI to the TR111, and prevents human power from branching to the variable base power supply VfiBI side.

TR111 is connected to multiple TRll6 to TR as shown in the figure.
111k are connected in parallel and human power A to K are applied to each base, the voltage of the variable base power supply VBB+ is supplied to at least one transistor among them (for example, TR111 as shown).

When multiple sets of ECLs shown in Fig. 1 are connected in cascade via emitter follower sections that constitute a buffer, the variable base power supply V11111 supplied to the base of TR111 and the emitter power supply (indicated by VEE□) of the preceding emitter follower are shared. (This configuration will be described in detail in the Examples section).

Note that each transistor portion configuring the ECL can be configured with one or more transistors.

In a burn-in method for applying thermal stress to an integrated circuit including each ECL configured as described above, the present invention provides the following features:
The voltage value of the base power supply VB□ of one transistor part TR111 constituting the current switch part of the ECL is set to a lower voltage value and a higher voltage value than the voltage value of the fixed base power supply VB B2 of the other transistor part TR112 of the current switch part. The voltage value of the one variable base power supply VB'BI is periodically changed to a lower voltage value and a higher voltage value than the other fixed base power supply V882 during burn-in, and the ECL current is switched. The device is configured to perform current switching of the portion.

[For production]

When performing burn-in, the collector power supply V of a burn-in device (not shown) is used. 0. The constant current power supply VEEI and the fixed base power supply IVaB□ respectively supply specified voltage values to the integrated circuit, but the variable base power supply VIIB1 is initially set to a voltage value lower than the fixed base power supply V a B2.

As a result, TR111 of each ECL is turned off, and T
R112 is turned on and burn-in is started.

This state does not change even if TR111 is a plurality of TR111° to TR111.

After a predetermined period of time after the burn-in is started, the burn-in device converts the variable base power supply Vs□ to the fixed base power supply VB.
The voltage changes to a higher voltage value than B□.

As a result, TR111 is switched from off to on, and TR112 is switched from on to off. TR1
11 to a plurality of TR111, -TR111, TRll1. is turned on. If the voltage of the variable base power supply V B B + is
If it is supplied to all of TRll1. -T
R111 can be switched from the entire state to the on state.

Hereinafter, T
R111 (TRI 11.-TRII 1i= )
and TR112 are alternately turned on or off, and current switching is performed.

As described above, there is no need to create various test patterns for switching the current switch section of each ECL.
By providing a variable base power supply V and variably controlling the base voltage of one transistor section, it is possible to perform good burn-in by switching the current switch sections of each ECL in the integrated circuit.

Furthermore, since it is not necessary to create various test patterns, and only the variable base power supply VBBI needs to be added, the burn-in device can be simplified.

Furthermore, in the case of a configuration in which a plurality of sets of ECLs shown in FIG. 2, it is possible to simplify the supply of the variable base voltage to each ECL and the supply circuit configuration without impairing the burn-in operation (the configuration and operation will be explained in the embodiment section).

[First example] A first embodiment of the present invention will be described with reference to FIG.

FIG. 2 shows the configuration of each ECL in the first embodiment.

(A) Structure of the first real distribution example In FIG. 2, T
R111, ~TRI 11. , TRI 12゜load resistance R121, R122, emitter constant current power supply VEEI + variable heath power supply VI] B++ fixed heath power supply VBB2+
Regarding collector power supply VCC and human power A-K,
As explained in the figure.

In this embodiment, the variable base power supply VBBI side has multiple T
RI 11. -TRI I L are connected in parallel,
The variable base power supply V e s + has a coupling resistance R120,
~TRll1. via R12L. - Connected to each base of TR111.

A transistor 113 (hereinafter referred to as TR113) constitutes an emitter follower together with a resistor 123 (hereinafter referred to as R123), and takes out the output from the common collector side of TR111 and TR111.

R123 on the emitter side of TR113 is connected to a fixed emitter power supply VEF,2.

114 is a transistor section (hereinafter referred to as TR114);
It constitutes an emitter follower together with a resistor 124 (hereinafter referred to as R124), and takes out the output from the collector side of TR112. R124 on the emitter side of TR114 is connected to emitter power supply VER2. The voltage value of the emitter power supply VEE2 is selected to be lower than the fixed base power supply VBR2 and to match the lower voltage value of the variable base power supply Vaa+.

As a result, the specified VCC + VBBI + VEEI
and V2):2 is applied, the variable base power supply V
B B1 is fixed at a predetermined voltage value lower than the base power supply VBB2, ie, V. When set to 2, it operates as a normal ECL. That is, the NOR output from input A to human power is taken out from the emitter output terminal of TR113, and TR'
The OR output of human power A to human power is taken out from the emitter output of l14.

A burn-in device (not shown) is connected to the collector power supply V described above.
. . , variable base power supply VBBl+fixed base power supply VB!
12+ constant current power supply VH1 and emitter power supply V, etc., and there is no need to provide a function of generating various test patterns for switching the current switch sections of each ECL. Therefore, the configuration of the burn-in device can be significantly simplified.

(B) Burn-in operation of the first embodiment When performing burn-in, the collector power supply V of the burn-in device. Each prescribed voltage value is supplied to the integrated circuit from the C1 constant current power supply V E E I and the fixed base power supply VBB2, but the variable base power supply VBB+ initially has a voltage value lower than the fixed base power supply v, 82, that is, the emitter power supply. Set to VB2. As a result, each EC in an unmanned state
L's TRll1. ~TRl11 are all turned off, TR112 is turned on, and burn-in is started.

After a predetermined period of time after burn-in is started, the burn-in device switches on the variable base power supply VB! 11 fixed base power supply V
Change the voltage value to higher than BB2.

As a result, TR111 to TR111 are switched from off to on, and TR112 is switched from on to off.

Similarly, the burn-in device periodically changes the voltage value of the variable base power supply vllIll to the fixed base power supply V B
By alternately changing the voltage value from a voltage value lower than B2 (Vpp2) to a voltage value higher than TRll1. ~TR111
Burn-in is performed by alternately switching the currents of the TR112 and TR112.

In addition, in this embodiment, the variable base power supply VBB+
and the emitter power supply VEE2 are made common, and the emitter voltage RV
Ep2 may also be changed. At this time, TR113 and TR114 of the emitter follower section also change according to changes in the variable base power supply VIIBl, but this does not interfere with the burn-in operation.

[Second example] A second embodiment of the invention will be described with reference to FIG.

FIG. 3 shows the configuration of each ECL in the second embodiment.

(A) Configuration of second embodiment In FIG. 3, TR111 constituting the second ECL,
-TR111, TR112, T'RII4, R120
,=R12(L= ,R121,R122,R124,
Collector power supply VCC, fixed base power supply VB! Regarding 121 constant current power supply Vl:□ and emitter power supply V2E2,
It is as explained in FIG.
Those marked with "R" indicate resistance).

In this embodiment, the variable base power supply V881 is shared with the emitter power supply VEE2, and the emitter power supply V-2 is the variable base power supply V[I B+ , which is lower than the fixed base power supply V B B 2 from the original voltage value of VEE2. V
It changes to a voltage value higher than IIR2. Also, TR111
The emitter follower section (TR113°R123) that takes out the NOR output from the common collector side of 6 to TR111b is deleted, and the OR output from TR112 is taken out from the emitter follower section of TR114A and is sent to the third ECL in the next stage.
It is configured to be input to

TR115, TR116, R125, R126° constant current power supply V, 1. Emitter power supply VEE2. RL201. Fixed base power supply VBB2 and collector power supply VCC constitute a current switch section, and TRll0. R120 and the emitter power supply VEE2 constitute an emitter follower section, and these constitute the first ECL. In addition, R120,
This is a resistor that connects the emitter power supply VRB2 to the base of TR115.

In this first ECL, input A is manually applied to the base of TR 115. TRll0 that constitutes the emitter follower section
R120 on the emitter side of is T of the second ECL in the next stage.
It is shared with the coupling resistance of the emitter power supply VEE2Δ of R111, and its emitter follower output becomes input A of TR111.

TRI 17. TR118, R127, R128゜ Constant current power supply VEE++ Fixed base power supply VB [12 and collector power supply VCC constitute a current switch section, TR119,
R129 and the emitter power supply VEE2 constitute an emitter follower section, and these constitute the third ECL. Third
In the ECL, the emitter follower output of TR114, which constitutes the emitter follower section of the second ECL, is output from TR117.
input to the base of

Note that in the first and third ECLs, the TR115 and TR117 may have a configuration in which a plurality of transistors are connected in parallel like the second ECL.

Thereafter, each ECL (not shown) is connected in cascade in the same manner.

(B) Burn-in operation emitter power supply V of the second embodiment. 2 to a specified voltage value lower than the fixed base power supply VBB2, and the other collector power supply V. C1
When the fixed base power supply VB112 and constant current power supply V6,1 are supplied with the specified voltage values, each ECL becomes a normal EC.
The burn-in operation is performed as L, and since the operation is clear from the previous explanation, the burn-in operation will be explained below.

When performing burn-in, as in the first embodiment, specified voltage values are supplied to the integrated circuit from the collector power supply V c c + constant current power supply V E E l and the fixed base power supply VB, 12, but the emitter The power supply VEE□ is initially set to an original voltage value lower than the fixed base power supply V+u+2.

As a result, TR115, TR111, -TR111k and TR of the current switch section of each ECL in an unmanned state
117 is turned off, and TR116, TR112 and TR118 are turned on. Further, TR110° TR114 and TR119 of each emitter follower section are both in the on state. Burn-in is started in such a conductive state.

After a predetermined period of time after the burn-in is started, a burn-in device (not shown) sets the emitter power supply VEE2 to a voltage value higher than the fixed base power supply VBB2. As a result, the TRI 15. of the current switch section of each ECL. TRI
11. ~TR111k and TR117 switch from off to on state, TR116, TR112 and TR11
8 switches from on to off state. On the other hand, TRI of each emitter follower section 10. TR114 and TR11'
9 maintain the on state.

Similarly, the burn-in device periodically changes the voltage value of the emitter power supply v9,2 from a voltage value lower than the fixed base power supply VBB2 (original VEE2 voltage value) to a voltage value higher than the fixed base power supply VBB2. The burn-in is performed by alternately switching the current switch parts of the burn-in.

Although the embodiments of the present invention have been described above, the embodiments of the present invention are not limited to these embodiments, but are applicable to integrated circuits having various known ECL components.

〔Effect of the invention〕

As explained above, according to the present invention, the following effects can be obtained.

(1) It is not necessary to create various test patterns for switching the current switch section of each ECL in the integrated circuit,
By providing a variable base power supply VBBI and variably controlling the base voltage of one transistor section, it is possible to perform good burn-in by switching the current switch sections of each ECL in the integrated circuit.

(2) Since it is not necessary to create various test patterns and it is only necessary to add the variable base power supply VBB+, the burn-in device can be simplified.

(3) When multiple sets of ECLs are connected in cascade via the emitter follower section that constitutes a buffer, if the variable base power supply of the ECL is shared with the emitter power supply of the emitter follower section in the previous stage, each set can be connected without impairing the burn-in operation. The supply of variable base voltage to the ECL and its supply circuit configuration can be simplified.

[Brief explanation of the drawing]

FIG. 1 is a diagram of the principle of the present invention. FIG. 2 is an explanatory diagram of the configuration of each ECL in the first embodiment of the present invention. FIG. 3 is a diagram of the configuration of each ECL in the second embodiment of the present invention. FIG. 4 is an explanatory diagram of the EcL and burn-in method of a conventional integrated circuit. In FIGS. 1 to 3, TRII 1 (TRII 1. to TR111,)
~TR119...Transistor section, R120 (RII
O6~RIIL, R120,)~R129 mountain resistance,
VCC... Collector power supply, V B B 1... Variable base power supply, V B B 2... Fixed base power supply, V
E E I ... constant current source, VEE2 ... emitter power supply.

Claims (1)

[Claims] 1. In an integrated circuit burn-in method that applies thermal stress to an integrated circuit including a plurality of emitter-coupled logic circuits ECL, (A) one of the current switch sections of the emitter-coupled logic circuit ECL; The voltage value of the base power supply (V_B_B_1) of the transistor part (TR111) can be changed to a voltage value lower and higher than the voltage value of the fixed base power supply (V_B_B_2) of the other transistor part (TR112) of the current switch part, (B) During burn-in, the voltage value of the one variable base power supply (V_B_B_1) is alternately changed to a lower voltage value and a higher voltage value than the other fixed base power supply (V_B_B_2), and the emitter-coupled logic circuit ( A burn-in method for integrated circuits characterized by: performing current switching in a current switch section of an integrated circuit (ECL). 2. The one transistor section (TR111) of the current switch section of the emitter-coupled logic circuit ECL is composed of a plurality of transistors (TR111_a to TR111_k) connected in parallel, and each transistor (TR111_a to T
R111_k) is connected to at least a portion of the variable base power supply (
2. The integrated circuit burn-in method according to claim 1, wherein a voltage of V_B_B_1) is supplied. 3. A plurality of sets of emitter-coupled logic circuits (ECL) are cascade-connected via emitter-follower sections constituting a buffer, and the variable base power supply (V_B_B_1) of the one transistor section (TR111) is connected to the emitter of the preceding emitter-follower section. 3. The integrated circuit burn-in method according to claim 1, wherein the integrated circuit burn-in method is shared with a power source (V_E_E_2).